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Background PNT2258 is a liposomal formulation that encapsulates multiple copies of PNT100, a native, chemically unmodified, 24-base DNA oligonucleotide designed to target the regulatory region upstream of the B-cell lymphoma 2 (BCL2) gene. Methods This phase II, multicenter, single-arm, open-label, 2-stage design study investigated the single-agent activity of PNT2258 in patients with relapsed/refractory DLBCL. Initially, patients had to have a performance status (PS) of ≤2 and prior exposure to CD20-targeted therapy, an alkylating agent, and a steroid with no upper limit. Criteria were modified to PS of 0 or 1 and at least 1 to ≤3 prior therapies (identified as the target population) after observing an initially high frequency of rapid disease progression in patients with extensive prior therapies or poor PS. Results The study was stopped early following an interim analysis, despite surpassing the protocol predetermined futility boundary, because the ORR was below the expectations of response in an evolving DLBCL treatment landscape. The final analysis included all 45 enrolled patients and demonstrated an ORR of 11%. In the response evaluable subset (n = 26), defined as patients in the target population with exposure to ≥8 doses of PNT2258 within the first 35 days and evaluable baseline/post-baseline scans, the ORR was 19%. The most common adverse events were fatigue (44%), nausea (42%), diarrhea (40%), pyrexia (36%), anemia (32%), and vomiting (27%). Conclusions PNT2258 was well-tolerated in a chemotherapy refractory DLBCL population. Despite demonstration of single-agent activity, ORR was lower than acceptable for further new therapy development.

Lessons Learned Subcutaneous injection was an effective route of administration for envafolimab with a favorable pharmacokinetic profile in patients with previously treated advanced solid tumors. Subcutaneous envafolimab was well tolerated and had durable antitumor activity at a wide range of doses and schedules. Envafolimab has the potential to be a more convenient option than currently approved intravenous PD-1/PD-L1 inhibitors. Background Envafolimab is a novel fusion of a humanized single-domain PD-L1 antibody and human IgG1 Fc fragment formulated for subcutaneous injection. This study explored the safety and feasibility of subcutaneous administration of envafolimab as an alternative to intravenous administration of PD-1/PD-L1 inhibitors in the treatment of advanced, refractory solid tumors. Methods This was a first-in-human, open-label phase I trial. In a dose-escalation phase, patients received subcutaneous envafolimab 0.01–10 mg/kg once weekly following a modified 3+3 design. In a dose-exploration phase, patients received subcutaneous envafolimab 300 mg once every 4 weeks. Results Twenty-eight patients were enrolled (dose escalation n = 18, dose exploration n = 10, median age 66 years; 71% male; ECOG performance score = 0 [21%] or 1 [79%]). No dose-limiting toxicities or injection-site reactions were reported. Envafolimab demonstrated dose-proportional increases in area under the time-concentration curve and maximum plasma concentration. Median time to maximum plasma concentration was 4–7 days. In the dose-exploration phase, terminal half-life was 14 days after dose 1 in cycle 1 and 23 days at steady state. Three patients experienced a confirmed partial response. Conclusion Subcutaneous envafolimab had a favorable safety and pharmacokinetic profile, with promising preliminary antitumor activity in patients with advanced solid tumors.

Background Wilms’ tumor 1 (WT1) is overexpressed in various malignancies. DSP-7888 Dosing Emulsion, also known as ombipepimut-S (United States Adopted Name; International Nonproprietary Name: adegramotide/nelatimotide), is an investigational therapeutic cancer vaccine comprising two synthetic peptides derived from WT1 to promote both cytotoxic T-lymphocyte (CTL) and helper T-lymphocyte–mediated immune responses against WT1-expressing tumors. Objective The aim of this study was to report the results from a phase I dose-escalation study (NCT02498665) that evaluated DSP-7888, administered either intradermally (ID) or subcutaneously (SC), in patients with recurrent or advanced malignancies associated with overexpression of WT1. Patients and Methods In this phase I dose-escalation study, patients with recurrent or advanced malignancies associated with overexpression of WT1 who progressed on, were intolerant to, or not a candidate for standard therapy or who presented with a malignancy that had no definite standard therapy received escalating doses of ID or SC DSP-7888 in a rolling-six study design. DSP-7888 3.5, 10.5, or 17.5 (ID only) mg was administered until disease progression or other discontinuation event. Primary objectives were safety, tolerability, and identification of the recommended phase II dose (RP2D). Overall survival (OS) and WT1-specific CTL induction were included as secondary and exploratory objectives, respectively. Results Twenty-four patients received either ID (3.5 mg, n = 4; 10.5 mg, n = 3; 17.5 mg, n = 3) or SC DSP-7888 (3.5 mg, n = 9; 10.5 mg, n = 5). No dose-limiting toxicity was observed. The most frequent treatment-emergent adverse event was injection site reactions (ID, 100% [10/10]; SC, 35.7% [5/14]); all were grade 1 or 2. Four patients (ID 17.5 mg, n = 1; SC 3.5 mg, n = 1; SC 10.5 mg, n = 2) had stable disease, 16 had progressive disease, and four were not evaluable. Median (95% confidence interval) OS duration was 180.0 (136.0–494.0) days. Among evaluable patients, WT1-specific CTL induction was observed in 66.7% (6/9) and 41.7% (5/12) of those administered ID and SC DSP-7888, respectively. Conclusions DSP-7888 Dosing Emulsion was well tolerated, with no dose-limiting toxicities, in patients with recurrent or advanced malignancies. Higher WT1-specific CTL induction activity was noted with ID compared with SC administration; because of this, the ID route was selected for further evaluation in the clinical program. Trial registration ClinicalTrials.gov identifier: NCT02498665. Supplementary Information The online version contains supplementary material available at 10.1007/s11523-021-00813-6.

PURPOSE This phase I study (RAD1901-005; NCT02338349) evaluated elacestrant, an investigational oral selective estrogen receptor degrader (SERD), in heavily pretreated women with estrogen receptor–positive, human epidermal growth factor receptor 2–negative metastatic breast cancer, including those with estrogen receptor gene alpha ( ESR1) mutation. The primary objective was to determine the maximum tolerated dose and/or recommended phase II dose (RP2D). METHODS The study consisted of a 3 + 3 design (elacestrant capsules) followed by expansion at RP2D (400-mg capsules, then 400-mg tablets) for the evaluation of safety and antitumor activity. Elacestrant was taken once daily until progression or intolerability. RESULTS Of 57 postmenopausal women enrolled, 50 received RP2D (400 mg once daily): median age, 63 years; median three prior anticancer therapies, including cyclin-dependent kinase 4,6 inhibitors (CDK4/6i; 52%), SERD (52%), and ESR1 mutation (circulating tumor DNA; 50%). No dose-limiting toxicities occurred; the most common adverse events at RP2D (400-mg tablet; n = 24) were nausea (33.3%) and increased blood triglycerides and decreased blood phosphorus (25.0% each). Most adverse events were grade 1-2 in severity. The objective response rate was 19.4% (n = 31 evaluable patients receiving RP2D), 15.0% in patients with prior SERD, 16.7% in patients with prior CDK4/6i, and 33.3% in patients with ESR1 mutation (n = 5/15). The clinical benefit rate (24-week) was 42.6% overall (n = 47 patients receiving RP2D), 56.5% (n = 23, ESR1 mutation), and 30.4% (n = 23, prior CDK4/6i). Elacestrant clinical benefit was associated with decline in ESR1 mutant allele fraction. CONCLUSION Elacestrant 400 mg orally once daily has an acceptable safety profile and demonstrated single-agent activity with confirmed partial responses in heavily pretreated patients with estrogen receptor–positive metastatic breast cancer. Notably, responses were observed in patients with ESR1 mutation as well as those with prior CDK4/6i and prior SERD. A phase III trial investigating elacestrant versus standard endocrine therapy is ongoing.

Purpose: Bromodomain and extraterminal (BET) proteins are key epigenetic transcriptional regulators, inhibition of which may suppress oncogene expression. We report results from 2 independent first-in-human phase 1/2 dose–escalation and expansion, safety and tolerability studies of BET inhibitors INCB054329 (study INCB 54329-101; NCT02431260) and INCB057643 (study INCB 57643-101; NCT02711137). Patients and Methods: Patients (≥18 years) with advanced malignancies, ≥1 prior therapy, and adequate organ functions received oral INCB054329 (monotherapy) or INCB057643 (monotherapy or in combination with standard-of-care) in 21-day cycles (or 28-day cycles depending on standard-of-care combination). Primary endpoints were safety and tolerability. Results: Sixty-nine and 134 patients received INCB054329 and INCB057643, respectively. Study INCB 54329-101 has been completed; INCB 57643-101 is currently active, but not recruiting (no patients were receiving treatment as of January 8, 2019). Terminal elimination half-life was shorter for INCB054329 versus INCB057643 (mean [SD], 2.24 [2.03] vs. 11.1 [8.27] hours). INCB054329 demonstrated higher interpatient variability in oral clearance versus INCB057643 (CV%, 142% vs. 45.5%). Most common (>20%) any-grade treatment-related adverse events were similar for both drugs (INCB054329; INCB057643): nausea (35%; 30%), thrombocytopenia (33%; 32%), fatigue (29%; 30%), decreased appetite (26%; 22%). Two confirmed complete responses and 4 confirmed partial responses with INCB057643 were reported as best responses. Conclusions: INCB057643 exhibited a more favorable PK profile versus INCB054329; exposure-dependent thrombocytopenia was observed with both drugs which limited the target inhibition that could be safely maintained. Further efforts are required to identify patient populations that can benefit most, and an optimal dosing scheme to maximize therapeutic index.

Background PNT2258 consists of a native, chemically unmodified, 24-base DNA oligonucleotide designed to target the regulatory region upstream of the BCL2 gene, delivered in a protective liposome. Derangement of BCL2-regulated control mechanisms is a defining characteristic of certain malignancies, and it was hypothesized that the oligonucleotide would promote anticancer activity via suppression of BCL2 transcription. Methods PNT2258 was evaluated in this, multicenter, nonrandomized, open-label Phase 2 study in 13 participants with relapsed/refractory B-cell malignancies to investigate potential antitumor activity and safety. Participants with follicular lymphoma, diffuse large B-cell lymphoma, mantle cell lymphoma, or chronic lymphocytic leukemia received intravenous PNT2258 120 mg/m2 on Days 1 to 5 of a 21-day cycle for up to 8 cycles, followed by 100 mg/m2 on Days 1 to 2 of a 28-day cycle until study withdrawal. Results All 13 participants were treated with PNT2258 monotherapy and evaluable for response and safety and tolerability. The overall response rate was 53.8% (7/13; 95% confidence interval [CI], 25.1%-80.8%). Median duration of response was 23.4 months (range, 3, 31.5). The disease control rate of participants with stable disease or better was 84.6% (95% CI, 54.6%-98.1%). The most frequently (≥50%) observed adverse events (AEs) were nausea, chills, diarrhea, fatigue, headache, vomiting, and back pain. Hypertension (30.8%) and diarrhea (23.1%) were the most frequent grade ≥3 AEs. No deaths were observed. Conclusion Clinically meaningful and durable activity with an acceptable safety profile was observed in participants with relapsed/refractory B-cell malignancies who received single-agent PNT2258. Trial registration NCT01733238, first posted 26-Nov-2012. https://clinicaltrials.gov/ct2/show/NCT01733238

BackgroundMicrosatellite-stable (MSS) and instability-low (MSI-L) metastatic colorectal cancer (mCRC) are typically characterised as ”immune-excluded/desert” tumour microenvironments lacking T-cell infiltration. Anti-PD-1 monotherapy has little clinical benefit in MSS/MSI-L mCRC1 and knowledge of the effects of PD-1 inhibition on T-cell activation/infiltration in this population is limited. Novel combination therapies to overcome anti-PD-1 resistance are required. SPICE is a multicentre, open-label, phase 1 study of the tumour-selective chimeric Ad11/Ad3 group B oncolytic adenovirus enadenotucirev plus nivolumab in patients with metastatic/advanced epithelial tumours refractory to standard therapy. Preliminary data from patients with MSS/MSI-L mCRC demonstrated a median overall survival of 14 months, manageable tolerability and intratumoural T-cell infiltration.2 Here we characterise the immunological effects of tumour re-engineering with enadenotucirev in combination with nivolumab in patients with MSS/MSI-L mCRC.MethodsPatients received increasing doses and/or cycles of intravenous enadenotucirev followed by up to 8 cycles of nivolumab as previously described.2 Wherever possible, pre- and post-treatment (~5 weeks post-first enadenotucirev) biopsies were collected; samples were analysed using immunohistochemistry and automated image analysis. Peripheral blood mononuclear cell immunophenotyping (multiparameter flow cytometry) and serum cytokines were assessed at multiple times.Results43 patients with mCRC were treated (86% MSS/MSI-L; 14% unknown). Among the 13 patients (12/13 MSS/MSI-L; 1/13 unknown) with matched biopsies, 11 had increased intratumoural and stromal CD8+ T-cell infiltration in post-treatment biopsies (median [Q1-Q3] fold changes 6.5× [1.5–25.4] and 1.9× [1.5–3.9], respectively; figure 1). CD4+ T-cell density increased in 10/13 patients and 8/13 patients had increased proportions of PD-L1+ immune cells. Increases in CD8 T-cell proliferation (Ki67; 7/9 patients) and cytolytic activity (Granzyme B; 7/13 patients) markers were seen. 4/13 patients converted from a ”desert” to an ”inflamed” immune phenotype (pathologist scored CD8/pan-cytokeratin staining). Immunophenotyping showed trends towards increased T-cell activation (CD38+ and HLA-DR+ CD8+ T cell populations) post-treatment (9/10 patients), including in one patient who had only received enadenotucirev prior to sampling. Persistent increases in inflammatory cytokines (IFNγ, IL-12p70, IL-17a) were seen in two patients from ~Day 15, including one who achieved a sustained objective response.Abstract 342 Figure 1Tumour immune cell infiltration following treatment with enadenotucirev plus nivolumabConclusionsThese data show that intravenous enadenotucirev plus nivolumab can induce immune infiltration/activation within MSS/MSI-L mCRC. These encouraging findings suggest that immune activation can be achieved even in ”immune-excluded/desert” tumours. SPICE has been closed following completion of dose-escalation. Efforts are now focused on the development of next-generation variants of enadenotucirev designed to further re-programme the tumour microenvironment by expressing immune-enhancer transgenes (T-SIGn vectors); these studies are ongoing (NCT04830592, NCT04053283, NCT03852511).AcknowledgementsThis study was funded by PsiOxus Therapeutics Limited and Bristol Myers Squibb. Medical writing support: Lola Parfitt, MRes, of PsiOxus Therapeutics Limited.Trial RegistrationEudraCT number2017-001231-39NCT number: NCT02636036ReferencesKawazoe A, Kuboki Y, Shinozaki E, et al. Multicenter phase I/II trial of napabucasin and pembrolizumab in patients with metastatic colorectal cancer (EPOC1503/SCOOP trial). Clin Cancer Res 2020;26:5887–5894.Fakih M, Wang D, Harb W, et al. SPICE: a phase I multicenter study of enadenotucirev in combination with nivolumab in tumors of epithelial origin: an analysis of the metastatic colorectal cancer patients in the dose escalation phase. Ann Oncol 2019:30(suppl_5):v252.Ethics ApprovalThe study was approved by the WCG Institutional Review Board (study approval number 20152656), UCLA Institutional Review Board (study approval number IRB#15-002010), Vanderbilt Institutional Review Board (study approval number IRB #171453) and Henry Ford Institutional Review Board (study approval number IRB #10349).

Background: DSP-7888—an investigational immunotherapeutic cancer vaccine derived from Wilms’ tumor 1 (WT1)—induced WT1-reactive T cells, the activity of which was maintained and enhanced by anti-PD-1 mAbs (preclinical; Goto, et al. ASH 2016). Results from the Ph 1b dose search cohort of a Ph 1b/2 study of DSP-7888 + immune checkpoint inhibitors (ICIs) NIV or PEM in ASTs (NCT03311334) are presented. Methods: Pts (aged ≥18 y; ECOG PS 0-1; locally advanced/metastatic solid tumors; approved for NIV or PEM) received intradermal (ID) DSP-7888 10.5 mg once weekly (wk) (Q1W) + NIV 240 mg IV Q2W for 4 (Arm 1) or PEM 200 mg IV Q3W for 6 (Arm 2) wks (induction), then DSP-7888 + NIV (Q2W; Arm 1) or PEM (Q3W; Arm 2) (maintenance). A DSP-7888 3.5-mg dose cohort would open if dose limiting toxicities (DLTs) occured in >1 of 6 pts. Primary objectives: evaluate safety (including DLTs) and identify the recommended Ph 2 dose of DSP-7888 + NIV or PEM. Results: At data cutoff (March 30, 2021), 13 pts (mean age 63.8 [range 38-82] y; 61.5% male; median 3 (1-5) lines of prior therapy; 84.6% prior ICIs) were enrolled and treated with DSP-7888 10.5 mg + NIV (Arm 1, n=7) or PEM (Arm 2, n=6). Treatment-emergent adverse events (TEAEs) were reported in 100% (any grade) and 76.9% (grade ≥3; most commonly injection site reactions [ISR; 30.8%]) of pts (Table). No DLTs occurred during the evaluation period (NIV, 4 wk; PEM, 6 wk), establishing 10.5 mg as the recommended dose for DSP-7888 + NIV or PEM. Serious AEs were reported in 7 (53.8%) pts (2 [15.4%] related to DSP-7888). At efficacy data cutoff (May 4, 2020), 2 (15.4%) pts with prior ICIs achieved partial response, which lasted 9.5 and 5.5+ months; 6 pts achieved stable disease (n=4 ≥8 months) and 3 had progressive disease. Conclusions: DSP-7888 + NIV or PEM was generally tolerable at 10.5 mg ID (most common TEAE was ISR) and showed evidence of preliminary antitumor activity. An expansion cohort in ovarian cancer is enrolling. Table. Safety and Efficacy (N=13a) DSP-7888 + NIV (n=7) DSP-7888 + PEM (n=6) Overall (N=13) Patient characteristics Prior lines of therapy, n (%) -1 0 1 (16.7) 1 (7.7) -2 2 (28.6) 1 (16.7) 3 (23.1) -≥3 5 (71.4) 4 (66.7) 9 (69.2) Prior ICI, n (%) 7 (100) 4 (66.7) 11 (84.6) Safety All patients with TEAE grade ≥3, n (%)b — — 10 (76.9) TEAEs grade ≥3 (in ≥2 patients), n (%)b -Injection site reaction — — 4 (30.8) Pts with treatment-emergent SAEs, any grade, n (%)b — — 7 (53.8) Efficacy ORR (CR+PR), n (%) [95% CI] 2 (28.6) [3.7, 71.0] 0 2 (15.4) [1.9, 45.5] Best overall response, n (%) -PRc 2 (28.6) 0 2 (16.7) -SD 3 (42.9) 3 (50.0) 6 (46.2) -PD 0 3 (50.0) 3 (23.1) -Non-CR/Non-PD 1 (14.3) 0 1 (7.7) -NE 1 (14.3) 0 1 (7.7) Disease control rate (CR+PR+SD+Non-CR/Non-PD), n (%) [95% CI] 6 (85.7) [42.1, 99.6] 3 (50.0) [11.8, 88.2] 9 (69.2) [38.6, 90.9] aTumor types included non-small cell lung cancer (n=7), urothelial cancer (n=3), gastroesophageal junction adenocarcinoma (n=1), head and neck squamous cell carcinoma (n=1), and renal cell carcinoma (n=1). For inclusion, patients either progressed on their prior treatment or were being treated with NIV or PEM, achieved at least SD, and could benefit from the addition of DSP-7888 (physician’s judgement). bRegardless of causality. cOf the patients that exhibited a PR, 1 had renal cell carcinoma and 1 had urothelial cancer. Both patients were previously treated with an ICI (NIV and atezolizumab, respectively. DOR w as 9.5 and 5.5 (+) months in the patients with renal cell carcinoma and urothelial cancer, respectively (DOR was defined as the time, in months, from the first documentation of CR or PR to the first documentation of PD or death due to any cause. Patients who were alive and progression-free as of the analysis cut-off date were censored (+) at their last date of response assessment. CI, confidence interval; CR, complete response; ICI, immune checkpoint inhibitor; DOR, duration of response; NE, not evaluable; NIV, nivolumab; ORR, overall response rate; PD, progressive disease; PEM, pembrolizumab; PR, partial response; SAE, serious adverse event; SD, stable disease; TEAE, treatment-emergent adverse event. Citation Format: Wael A. Harb, Makoto Origuchi, Patrick W. Cobb, Trisha Wise-Draper, Natsuko Suginobe, Megumi Nakamura, Masashi Goto, Aaron Chen, Jian Li, James Wade III. Preliminary safety and efficacy of DSP-7888 plus nivolumab (NIV) or pembrolizumab (PEM) in patients (pts) with advanced solid tumors (ASTs): A phase (Ph) 1b/2 open-label study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT135.

BACKGROUND Five-year overall survival (OS) for patients with unresectable stage III non-small cell lung cancer (NSCLC) is poor. Until recently, a standard of care was concurrent chemoradiation alone. Patients with metastatic NSCLC treated with anti-programmed death 1 antibodies have demonstrated improved OS. This trial evaluated pembrolizumab as consolidation therapy after concurrent chemoradiation in patients with unresectable stage III disease. METHODS Patients with unresectable stage III NSCLC received concurrent chemoradiation with cisplatin and etoposide, cisplatin and pemetrexed, or carboplatin and paclitaxel and 59.4 to 66.6 Gy of radiation. Patients with nonprogression of disease were enrolled and received pembrolizumab (200 mg intravenously every 3 weeks for up to 12 months). The primary endpoint was the time to metastatic disease or death (TMDD). Secondary endpoints included progression-free survival (PFS) and OS. RESULTS The median follow-up for 93 patients (92 for efficacy) was 32.2 months (range, 1.2-46.6 months). The median TMDD was 30.7 months (95% confidence interval [CI], 18.7 months to not reached), which was significantly longer than the historical control of 12 months (P

This abstract was not presented at the symposium.

Introduction Lemzoparlimab (also known as TJ011133 or TJC4) is a differentiated CD47 IgG4 antibody targeting a distinct CD47 epitope to enable a unique red blood cell sparing property, while retaining strong anti-tumor activity as demonstrated previously in patients with solid tumors. Lemzoparlimab does not induce significant hematologic toxicity without the need of priming dosing commonly required for other CD47 antibodies. Lemzoparlimab exhibits an enhanced treatment effect when combined with rituximab in lymphoma animal models. Methods This ongoing Phase 1b study (NCT03934814) enrolled relapsed and refractory (R/R) patients with CD20 positive Non-Hodgkin's Lymphoma (NHL) who had at least two prior lines of therapy in a 3+3 dose escalation design followed by a dose expansion. Lemzoparlimab was administered intravenously at doses of 20 or 30 mg/kg weekly with rituximab (375 mg/m2 QW for 5 doses followed by once monthly for 3 doses). Safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD) and anti-tumor activity based on Lugano criteria were assessed. Preliminary data as of 2 July 2021 are reported here with the updated data set to be presented at the 2021 ASH meeting. Results Eight heavily pre-treated patients with R/R NHL who had progressed on prior CD20 targeted therapies were enrolled to the dose cohorts of 20 mg/kg (n=6) and 30 mg/kg (n=2) of lemzoparlimab in combination with rituximab. The diagnoses included diffuse large B-cell lymphoma (DLBCL) [n=2], mantle cell lymphoma (MCL) [n=1], and follicular lymphoma (FL) [n=5]. Patients had a median age of 63 years (range: 43-83) and a median of 4 prior therapies (range: 2-10). Safety and tolerability: The most common treatment-related adverse events (TRAEs) were infusion-related reactions (n=4), pruritus (n=3), fatigue (n=3), rash (n=2), constipation (n=2), and dyspnea (n=2). All TRAEs were Grade 1 or 2, with one exception who reported Grade 3 TRAEs including pleural effusion, tachycardia, cough, pruritis, fatigue, rash and dyspnea, at 20 mg/kg dose level. Mild hematologic AEs were observed as one isolated episode of anemia and thrombocytopenia, respectively, and no treatment was required. PK and PD: Co-administration of rituximab did not affect the PK or immunogenicity of lemzoparlimab. On average, 80% and 90% CD47 receptor occupancy was detected in biopsied lymph nodes from the patients dosed at 20 and 30 mg/kg, respectively, indicating significant tumor target engagement. Anti-tumor activity: Among 7 efficacy-evaluable patients, 3 complete responses (CR) [1 transformed FL-DLBCL + 2 FL] and 1 partial response (PR) of FL were observed (ORR=57%), together with 3 stable disease (SD duration between 3-6 months). The overall DCR was 100%. Tumor shrinkage was observed in all evaluable patients. One patient was not efficacy evaluable due to clinical disease progression after withdrawal from the study at the first cycle. The median time to an initial response to the treatment was 2 months and all responders remained in clinical response at time of data cutoff. During continued treatment, two patients developed improved responses. One patient with transformed FL-DLBCL improved from PR at 2 nd month to CR at 8 th month and another patient with FL improved from SD at 2 nd month to PR at 4 th month. Conclusion Consistent with the previously reported monotherapy results, lemzoparlimab given at 20 - 30 mg/kg with rituximab is safe and well tolerated in patients with R/R NHL without the need for a priming dose. A high level of intra-tumoral target engagement was reached at both dose levels. The combination therapy exhibited evidence of clinical activity in heavily pre-treated R/R NHL patients who had progressed on prior CD20 targeted therapies. The results provide the basis for RP2D and impetus for accelerated clinical development for NHL. Disclosures Mehta: Seattle Genetics; Incyte; TG Therapeutics: Consultancy; Seattle Genetics; Incyte; TG Therapeutics: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Affirmed; Kite/Gilead; Roche-Genetech; Celgene/BMS; Oncotartis; Innate Pharmaceuticals; Seattle Genetics; Incyte; Takeda; Fortyseven Inc/Gilead; TG Therapeutics; Merck; Juno Pharmaceuticals/Bristol Myers Squibb: Research Funding. Xu: I-Mab Biopharma: Current Employment. Meng: I-Mab Biopharma: Current Employment. Lee: I-Mab Biopharma: Current Employment. Yuan: I-Mab Biopharma: Current Employment. Wang: I-Mab Biopharma: Current Employment. Song: I-Mab Biopharma: Current Employment. Shen: I-Mab Biopharma: Current Employment. Gopal: Genetech: Consultancy, Honoraria, Research Funding; Gilead: Consultancy, Honoraria, Research Funding; Teva: Research Funding; I-Mab bio: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Nurix Inc: Consultancy, Honoraria; Agios: Research Funding; Servier: Consultancy, Honoraria; ADC Therapeutics: Consultancy, Honoraria; Cellectar: Consultancy, Honoraria; Acrotech: Consultancy, Honoraria; Merck: Consultancy, Honoraria, Research Funding; Karyopharm: Consultancy, Honoraria; Takeda: Research Funding; MorphoSys: Honoraria; Kite: Consultancy, Honoraria; Beigene: Consultancy, Honoraria; Epizyme: Consultancy, Honoraria; Bristol Meyers Squibb: Research Funding; Astra-Zeneca: Research Funding; IGM Biosciences: Research Funding; Incyte: Honoraria; SeaGen: Consultancy, Honoraria, Research Funding.

BACKGROUND: Checkpoint inhibitors (CPI) targeting the PD-1 and CTLA-4 pathways have demonstrated significant clinical benefit in multiple tumors, but the majority of patients exhibit or develop resistance, at least in part due to insufficient activation and/or excessive exhaustion of tumor-specific T cells. Strong preclinical rationale exists to combine CPIs with T cell costimulatory agonists, but such approaches have not yet translated into significantly improved clinical benefit. The majority of these approaches, though, have not targeted CD28, a critical T cell costimulator recently recognized as a key target of checkpoint inhibition. ALPN-202 is a variant CD80 vIgD-Fc fusion that mediates PD-L1-dependent CD28 costimulation and inhibits the PD-L1 and CTLA-4 checkpoints. As monotherapy, ALPN-202 has demonstrated superiority to CPI-only therapies in tumor models, while demonstrating a favorable safety profile in preclinical toxicology studies. METHODS: This is a cohort-based, open-label dose escalation and expansion study in adults with advanced solid tumors or lymphoma (NCT04186637). The objectives of this study are to evaluate the safety, efficacy, pharmacokinetics, anti-drug antibodies, and pharmacodynamics of ALPN-202. Subjects who are refractory or resistant to standard therapy (including approved CPIs), or without available standard or curative therapy are eligible. ALPN-202 is administered by IV infusion. After two single-subject cohorts (0.001 mg/kg, 0.01 mg/kg), a standard 3+3 dose escalation (0.1-20 mg/kg) has been implemented with two dose schedules in parallel, Q1W and Q3W. Thereafter, expansion cohorts are planned to enroll subjects at a selected dose regimen(s) in selected indications. Biomarkers include tumor measurements of PD-L1, CD28, CD80 and CD86 to explore the possible relationship between baseline expression and outcomes. Other pharmacodynamic analyses include target saturation, inflammatory cytokines and immunophenotyping of circulating leukocytes. As of January 2021, the trial is continuing as planned; no DLTs have been observed through the 0.3 mg/kg cohorts (dose level 4). Citation Format: Mark Voskoboynik, Justin C. Moser, Nehal Lakhani, Michael Millward, Diwakar Davar, Wael A. Harb, Jing Yang, Gary Means, Kristi Manjarrez, Almudena Tercero, Hany Zayed, Jan Hillson, Christine Dela Cruz, Graciela Perez, Stanford L. Peng. NEON-1: a first-in-human phase I open-label study of ALPN-202, a conditional CD28 costimulator and dual checkpoint inhibitor, in advanced malignancies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT213.

Elotuzumab, an immunostimulatory SLAMF7-targeting monoclonal antibody, induces myeloma cell death with minimal effects on normal tissue. In a previous phase 3 study in patients with relapsed/refractory multiple myeloma (RRMM), elotuzumab (10 mg/kg, ∼3-h infusion), combined with lenalidomide and dexamethasone, demonstrated durable efficacy and acceptable safety; 10% (33/321) of patients had infusion reactions (IRs; Grade 1/2: 29; Grade 3: 4). This phase 2 study (NCT02159365) investigated an accelerated infusion schedule in 70 patients with newly diagnosed multiple myeloma or RRMM. The primary endpoint was cumulative incidence of Grade 3/4 IRs by completion of treatment Cycle 2. Dosing comprised elotuzumab 10 mg/kg intravenously (weekly, Cycles 1-2; biweekly, Cycles 3+), lenalidomide 25 mg (daily, Days 1-21), and dexamethasone (28 mg orally and 8 mg intravenously, weekly, Cycles 1-2; 40 mg orally, weekly, Cycles 3+), in 28-day cycles. Premedication with diphenhydramine, acetaminophen, and ranitidine (or their equivalents) was given as in previous studies. If no IRs occurred, infusion rate was increased in Cycle 1 from 0.5 to 2 mL/min during dose 1 (∼2 h 50 min duration) to 5 mL/min for the entire infusion by dose 3 and also during all subsequent infusions (∼1-h duration). Median number of treatment cycles was six. No Grade 3/4 IRs occurred; only one Grade 1 and one Grade 2 IR occurred, both during the first infusion. These data support the safety of a faster infusion of elotuzumab administered over ∼1 h by the third dose, providing a more convenient alternative dosing option for patients.

2547 Background: Strong preclinical rationale has emerged for combining checkpoint inhibition (CPI) with T cell costimulatory agonists, particularly CD28, a critical T cell costimulatory molecule recently recognized as a key target of checkpoint inhibition. ALPN-202 is a variant CD80 vIgD-Fc fusion that mediates PD-L1-dependent CD28 costimulation and inhibits the PD-L1 and CTLA-4 checkpoints. It has demonstrated superiority to CPI-only therapies in tumor models, while demonstrating favorable safety in preclinical toxicology studies. Methods: This is a cohort-based, open-label dose escalation and expansion study of ALPN-202 in adults with advanced solid tumors or lymphoma (NCT04186637). Subjects with cancers refractory to standard therapies (including approved CPIs), or cancers without available standard or curative therapy are eligible. After two planned single-subject cohorts, a standard 3+3 dose escalation has been implemented with two dose schedules in parallel, Q1W and Q3W. Objectives include evaluation of safety and tolerability, PK, PD and preliminary anticancer activity of ALPN-202. Disease assessments are evaluated by RECIST v1.1 for solid tumors or by Lugano Classification for lymphoma. Results: As of January 2021, 20 subjects with advanced malignancies have received ALPN-202. Dose-dependent PK and target saturation have been preliminarily observed. So far, ALPN-202 has been well tolerated at dose levels ranging from 0.001 to 1 mg/kg weekly, with no DLTs. Low-grade skin toxicities (grade 1-2 rash) have been observed in 4 subjects (20%). Among 11 evaluable subjects, an unconfirmed partial response has been observed in one subject with colorectal carcinoma, while stable disease has been observed in 5 subjects with colorectal carcinoma, mesothelioma (2), cholangiocarcinoma, and renal cell carcinoma -- for a preliminary clinical benefit (PR+SD) rate of 100% (4/4) at dose levels of 0.3 mg/kg and higher, or 54% (5/11) overall (table). The meeting presentation will update this data, which is expected to include the conclusion of Q1W dose escalation, as well as immune correlates. Conclusions: First-in-human dose escalation with ALPN-202 has been well tolerated at doses capable of engaging CD28 costimulation in vivo in association with dual PD-L1/CTLA-4 checkpoint inhibition, with early signs of anti-tumor activity. These findings suggest that CD28 agonism can be safely achieved in humans, and further suggest that dose expansion with ALPN-202 is warranted to assess the relevance of controlled CD28 costimulation as a novel approach to cancer immunotherapy. Clinical trial information: NCT04186637. [Table: see text]

2521 Background: LVGN6051, a monoclonal antibody against CD137 (also known as 4-1BB or TNFRSF9) with an engineered Fc capable of selectively binding to the Fcγ receptor IIB, acts as a conditional CD137 agonist, resulting in immune activation optimally in tumor microenvironment ( Qi, Nat. Commun. 2019 ). In preclinical models, LVGN6051 demonstrated robust anti-tumor efficacy and safety as a single agent and in combination with anti-PD-1 antibodies. Therefore, we have initiated this first-in-human study of LVGN6051 alone or in combination with pembrolizumab for the treatment of advanced or metastatic malignancy. Methods: This study includes accelerated dose escalation monotherapy up to 2 mg/kg of LVGN6051, and traditional 3 + 3 design for higher doses of LVGN6051 alone or in combination with pembrolizumab. Then, this study will enroll patients with specific types of malignancies following Simon’s two-stage design. Both agents are administered once every 3 weeks. Primary objectives of this study were to define the safety profile and to establish the recommended phase 2 dose (RP2D) of LVGN6051 alone or in combination with pembrolizumab. Pharmacokinetics, immunogenicity, pharmacodynamics and clinical efficacy will be also evaluated. Results: At the cut-off date on January 18, 2021, 16 subjects have been enrolled into the monotherapy cohorts (n=12, no DLT observed up to 7 mg/kg), and the combination cohort (n=4, ongoing at LVGN6051 2 mg/kg and pembrolizumab 200 mg, one DLT observed). No treatment-related adverse event (TRAE) was observed in monotherapy. Treatment-emergent adverse events (TEAE) in combination included increased ALT/AST, thrombocytopenia, and fatigue. In the combination cohort, one patient with predominant hepatic metastases and history of intermittent grade 2 hepatic impairment experienced grade 3 increased ALT/AST (DLT) on cycle 1 day 15 that were resolved to her baseline without corticosteroids on cycle 1 day 18. TRAE included increased ALT/AST, thrombocytopenia, neutropenia, nausea and fatigue. Seven of 10 evaluable patients in the monotherapy cohorts demonstrated stable disease with the longest treatment being 8+ months. Tumor reductions by >10% were observed in melanoma and neuroendocrine tumor on monotherapy. One patient with metastatic head and neck squamous cell carcinoma who had progressed on an anti-PD-L1 based therapy showed an immune partial response (iPR) for 6+ months to the combination therapy. Conclusions: Preliminary evidence showed that LVGN6051 was well tolerated and tumor shrinkages were observed. While we continue assessing its safety profile, antitumor activity was observed in the LVGN6051 and pembrolizumab cohort. The favorable safety profile and preliminary antitumor activity warrant further evaluation in patients with advanced malignancies. Clinical trial information: NCT04130542.

9110 Background: AXL, a receptor tyrosine kinase, is over-expressed in many cancers, and has been identified as a marker of poor prognosis in NSCLC. AXL overexpression is implicated in development of resistance to EGFR inhibitors including erlotinib (Erl) and osimertinib. AXL inhibition by bemcentinib (Bem), a first-in-class, oral, selective and potent AXL kinase inhibitor, abrogates resistance to EGFR inhibitors in vivo. Bem is currently under evaluation as a monotherapy and in combination with EGFRi, CPIs and chemotherapy across several PhII trials. Methods: Phase I of this study was designed to confirm safety/tolerability of Bem in NSCLC pts as monotherapy and in combination with Erl in pts previously progressing on Erl (arm A). In Phase II, pts who had progressed on an approved EGFRi (arm B) or who were responding/stable on Erl in the 1L setting (arm C) were treated with Bem 200mg and Erl 150mg od to evaluate the safety and activity of the combination, assessing reversal or prevention of resistance to EGFR inhibition in these 2 groups, respectively. Plasma protein biomarker levels were sequentially measured using the DiscoveryMap v3.3 panel (Myriad RBM). Results: As of 7 Oct 2020, all arms have completed recruitment. Median exposure to Bem was 63d (mean: 200d, range: 2d-1175d). Treatment was generally well-tolerated. Common TRAEs (>20% pts) were diarrhea (70%; G3 20%), nausea (50%; G3 0%), QTc prolongation (35%; G3 3%), vomiting (35%; G3 0%), and fatigue (25%; G3 5%). 1 unrelated G4, 0 G5 reported. In the run-in arm (5 female, median age 61 yrs [57-76]), 2/8 pts achieved SD for ̃1 yr, including 19% tumor shrinkage in 1 pt. In arm A (5 female, median age 58 yrs [38-67]), 1/8 pts (68 F) achieved tumor shrinkage of 38%, with treatment duration of 2 yrs until progression. A further 5 pts reported SD. In arm B, 11 pts (7 female, median age 63 yrs [49-78]) had received a median of 1 (0 - 4) prior lines of chemotherapy and a median of 2 prior lines of EGFRi. One achieved a PR (51M) and one a SD (62F) on the combination (CBR of 18%); durations on treatment were 1 yr, and 6 mos, respectively. Neither had EGFR T790M. mPFS was 1.4 mos. In arm C, 13 pts (10 female, median age 66 yrs [32-80]) were enrolled. 11/13 pts were evaluable for efficacy. 1 PR (58M) was reported with 47% tumor shrinkage, duration of treatment was 315d. 9 other pts achieved SD (CBR of 91%), including 4 (3 F/1 M, age range 64-71yrs) who continued on trial for 772+ to 1008+ d. mPFS is currently 12.2 mos. Protein biomarkers predictive of pt benefit upon Bem treatment are being explored. Conclusions: Bem with Erl combination is feasible and tolerable in NSCLC pts, with benefit was seen in a subset of pts who either progressed on an EGFRi or were receiving Erl concurrently in remission in the first line. Further studies of Bem + EGFRi are warranted to explore the potential benefits of this combination. Clinical trial information: NCT02424617.

9100 Background: Viagenpumatucel-L (HS-110) is an allogeneic cell therapy derived from a human lung adenocarcinoma cell line incorporating multiple cancer testis antigens and transfected with a gp96-Ig fusion protein. Methods: We report interim results of cohort A (previously treated pts who had not received a checkpoint inhibitor [CPI]) and cohort B (pts who progressed after CPI treatment) in an ongoing phase 2 trial evaluating HS-110 plus nivolumab (NIVO) in advanced NSCLC pts (NCT02439450). Pts received HS-110 (1×107 cells) intradermally QW for 18 wk and NIVO Q2W until tumor progression. Stratified analyses were performed by injection site reaction (ISR), yes (+) or no (–); baseline blood tumor mutational burden (bTMB), bTMB-L (5% of pts included fatigue, maculopapular rash, nausea, diarrhea, and pruritus. Few HS-110–related TEAEs led to discontinuation of treatment [cohort A, 5 (10.6%); cohort B, 3 (4.4%)], and no serious AEs were considered related to HS-110. Conclusions: HS-110 was well tolerated when administered in combination with NIVO. In previously treated pts with advanced NSCLC, we observed (1) significantly longer PFS and OS in ISR+ pts in both CPI naïve and CPI progressor cohorts; (2) significantly longer OS in PD-L1+ patients in the CPI naïve cohort; and (3) a trend of improved OS in bTMB-L pts in the CPI progressor cohort. Further clinical evaluation of HS-110 is warranted in both CPI naïve and CPI progressor NSCLC patients. Clinical trial information: NCT02439450. [Table: see text]

Purpose: Additional targeted therapeutics are needed for the treatment of lymphoma. Abexinostat is an oral pan-histone deacetylase inhibitor (HDACi) displaying potent activity in preclinical models. We conducted a multicenter phase I/II study (N = 55) with single-agent abexinostat in relapsed/refractory lymphoma. Experimental Design: In phase I, 25 heavily pretreated patients with any lymphoma subtype received oral abexinostat ranging from 30 to 60 mg/m2 twice daily 5 days/week for 3 weeks or 7 days/week given every other week. Phase II evaluated abexinostat at the maximum tolerated dose in 30 patients with relapsed/refractory follicular lymphoma or mantle cell lymphoma. Results: The recommended phase II dose was 45 mg/m2 twice daily (90 mg/m2 total), 7 days/week given every other week. Of the 30 follicular lymphoma and mantle cell lymphoma patients enrolled in phase II, 25 (14 follicular lymphoma, 11 mantle cell lymphoma) were response-evaluable. Tumor size was reduced in 86% of follicular lymphoma patients with an investigator-assessed ORR of 64.3% for evaluable patients [intent-to-treat (ITT) ORR 56.3%]. Median duration of response was not reached, and median progression-free survival (PFS) was 20.5 months (1.2–22.3+). Of responding follicular lymphoma patients, 89% were on study/drug >8 months. In mantle cell lymphoma, the ORR was 27.3% for evaluable patients (ITT ORR 21.4%), and median PFS was 3.9 months (range, 0.1–11.5). Grade 3–4 treatment-related adverse events (phase II) with ≥10% incidence were thrombocytopenia (20%), fatigue (16.7%), and neutropenia (13.3%) with rare QTc prolongation and no deaths. Conclusions: The pan-HDACi, abexinostat, was overall well tolerated and had significant clinical activity in follicular lymphoma, including highly durable responses in this multiply relapsed patient population. Clin Cancer Res; 22(5); 1059–66. ©2015 AACR.

9546 Background: Viagenpumatucel-L (HS-110) is an allogeneic cellular vaccine derived from a human lung adenocarcinoma cell line transfected with gp96-Ig fusion protein. Gp96-Ig functions as an antigen chaperone for dendritic cell activation and direct CD8+T cell expansion via cross presentation. DURGA is a multi-cohort study evaluating HS-110 plus anti-PD-1 mAbs in patients (pts) with advanced NSCLC. We report on Cohort A, which enrolled previously-treated pts who had not received an anti-PD(L)1 prior to study entry. Methods: Primary objectives were safety and objective response rate (ORR). Overall Survival (OS) was a secondary endpoint. Pts received 1 X 107 HS-110 cells intradermally every week for 18 wks and nivolumab until tumor progression. To determine cancer testis antigen (CTA) overexpression from baseline pt tumor samples, hybrid-capture RNA-seq libraries were prepared from macrodissected formalin fixed paraffin embedded tumor tissue and sequenced on an Illumina NovaSeq 6000. Gene-level transcripts were quantified using the Salmon software package. Results: 47 pts were enrolled into Cohort A. ORR and clinical benefit rate (CR + PR + SD) were 21% and 43%, respectively, with a 17.2 month median duration of response. Median OS was 28.7 months (mos), with a median follow up of 15.7 mos. One and 2-year survival were 57% and 36%, respectively. A prespecified exploratory analysis of CTA expression level in baseline pt tumor tissue was performed. 50% of pts shared at least 8 of the 39 total antigens overexpressed by HS110. Although there was no difference in ORR between these groups, mOS was higher in pts with tumors that shared ≥ 8 antigens with HS-110 (not reached (NR) [95%CI: 10.3 mos, NR] vs 6.7 mos [95%CI: 1.4 mos, NR]), p = 0.028. Pts whose tumors expressed the ZNF492 antigen also had improved OS (NR [95%CI: 11.6 mos, NR] vs 7.2 mos [95%CI: 1.6 mos, NR]), p = 0.03. All pts experienced at least one adverse event (AE), and the most common AEs were fatigue (28%), arthralgia (19%) and cough (17%). There were 2 grade 5 AEs not related to treatment. Conclusions: The combination of HS-110 and nivolumab appears safe and well tolerated. OS was improved in pts whose tumors express ≥ 8 shared antigens with HS110, as well as in those who specifically expressed ZNF492. Further exploration of antigen expression as a predictor for treatment outcome with HS110 plus nivolumab is ongoing. Clinical trial information: NCT02439450 .

8017 Background: LAM-002 is a selective inhibitor of PIKfyve that disrupts lysosomal homeostasis, inducing cytotoxicity in B-cell lymphoma models as monotherapy or with anti-CD20 or anti-PDL1 antibodies (Gayle et al., Blood 2017;129(13):1768). Methods: In this study, patients received LAM-002 orally 2-3 times per day (BID or TID) in a 3+3 escalation. Additional patients received LAM-002 125 mg BID as monotherapy; with rituximab 375 mg/m2 intravenously (IV) and or subcutaneously weekly (Q1W) x 4 → Q8W x 4; or atezolizumab 1200 mg IV Q3W until disease progression or unacceptable toxicity. Pharmacokinetics (PK) were assessed for 8 hours postdose on Days 1 and 8. Efficacy was evaluated Q6-12W. Results: The study enrolled 62 patients (M:F n = 32/30); median [range] age = 69 [46-89] years; with diagnoses (n) of diffuse large B-cell lymphoma (25), follicular lymphoma (19), marginal zone lymphoma (8), mantle cell lymphoma (5), or chronic lymphocytic leukemia (5) to receive LAM-002 alone (n) at 50 mg BID (3), 100 mg BID (8), 150 mg BID (8), 75 mg TID (4), or 125 mg BID (20); LAM-002/rituximab (12); or LAM-002/atezolizumab (7). During LAM-002 dose-ranging (50 mg BID → 100 mg BID → 150 mg BID → 75 mg TID → 125 mg BID) transient, reversible nausea and/or diarrhea occurred at 150 mg BID and 75 mg TID, resulting in a LAM-002 recommended Phase 2 dosing regimen (RP2DR) of 125 mg BID. Among 39 patients receiving LAM-002, 125 mg BID, alone or in combination for up to 22 cycles (1.9 years), adverse events were typically low-grade. LAM-002 PK showed rapid absorption, dose proportionality, minimal accumulation, and no substantive changes with rituximab or atezolizumab coadministration. In patients with follicular lymphoma and median [range] prior therapies = 3 [1-9] treated with the RP2DR, objective response rates were 2/7 (29%; 1 complete response [CR], 1 partial response [PR]) with LAM-002, 5/8 (63%; 1 CR, 4 PRs) with LAM-002/rituximab, and 2/2 (100%; 2 PRs) with LAM-002/atezolizumab. Conclusions: LAM-002, the first clinical PIKfyve inhibitor, is safe alone or with full-dose anti-CD20 or anti-PD-L1 inhibition. LAM-002 does not cause the myelosuppressive or immune adverse events associated with lenalidomide or PI3K inhibitors. Promising efficacy supports registration-directed Phase 2/3 testing of LAM-002 monotherapy and combination therapy for patients with previously treated follicular lymphoma. Clinical trial information: NCT02594384 .

Background: Viagenpumatucel-L (HS-110) is an allogeneic cellular vaccine derived from a human lung adenocarcinoma (Ad) cell line transfected with the gp96-Ig fusion protein that functions as an antigen chaperone for cross-presentation and dendritic cell activation. In this context, gp96 serves as a potent immune adjuvant via Toll-like receptor 4/2 signaling, which serves to activate APCs to specialized dendritic cells as wells as cross-presentation of the gp96-chaperoned cancer testis peptide antigens (up to 725 represented) directly to MHC class I molecules for direct activation and expansion of CD8+ T-cells. DURGA is a multicohort study evaluating the combination of HS-110 and anti-PD-1 monoclonal antibodies in patients with advanced NSCLC. We report on Cohort A, which enrolled previously treated patients who have not received a checkpoint inhibitor prior to study entry. Methods: Patients (pts) with previously treated NSCLC received 1 X 107 HS-110 cells intradermally every week for 18 weeks, and standard-of-care nivolumab IV until intolerable toxicity or tumor progression. Tissue was tested at baseline for PD-L1 expression (≥ 1% or < 1%) and tumor-infiltrating lymphocytes (TILs). TIL high was defined by more than 10% CD8+ lymphocytes in the tumor stroma. The primary objectives were safety and objective response rate (ORR). Results: As of the March 2019 enrollment cut-off, there were 46 pts enrolled into cohort A (43 Ad and 3 squamous cell carcinoma), 6 (13%) of whom were EGFR positive. 9 pts (20%) were TIL high, 13 (28%) TIL low, and 24 (52%) TIL unknown. 8 pts (17%) were PD-L1 ≥ 1%, 21 (46%) were PD-L1 < 1%, and 17 (37%) were PD-L1 unknown. ORR was 22% and clinical benefit rate (objective response plus stable disease) was 48%. Median progression-free and overall survival were 1.9 and 16.9 months, respectively, with a median follow-up of 17 months. One- and 2-year survival were 48% and 30%, respectively. There were no statistically significant differences in subgroup analyses of PFS or OS based on TIL or PD-L1. In a prospectively defined secondary analysis, the presence of at least one injection site reaction (ISR) during treatment was associated with improved progression-free and overall survival: mPFS 6.1 vs. 1.6 months (HR 0.51 [95% CI 0.26, 0.97] p = 0.04), and mOS 42.1 vs. 5.9 months (HR 0.14 [95% CI 0.05, 0.36] p < 0.0001). 46 (100%) pts experienced at least one adverse event (AE), of which 29 (63%) were grade 1 or 2. The most common AEs were fatigue (26%), cough and arthralgia (17% each), and decreased appetite, constipation, and diarrhea (15% each). There were 2 grade 5 AEs (pulmonary embolism and acute MI) and 1 grade 4 AE (hyponatremia), none of which were considered to be treatment related. Conclusions: The combination of HS-110 and nivolumab appears safe and well tolerated. Efficacy results are independent of TIL and PD-L1 levels, whereas the occurrence of ISR is associated with improved progression-free and overall survival. Citation Format: Daniel Morgensztern, Lyudmila Bazhenova, Saiama N. Waqar, Lori McDermott, Jeff Hutchins, Wael Harb, Nathan Pennell, Roger B. Cohen. Viagenpumatucel-L (HS-110) plus nivolumab in previously treated patients with advanced non-small cell lung cancer (NSCLC) [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2019 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(3 Suppl):Abstract nr B31.

Background: The majority of patients (pts) with advanced ER+ breast cancer (BC) will experience progression of disease after endocrine therapy (ET) due to acquired resistance, including development of ESR1 mutations (mut). Response to conventional ET agents, including aromatase inhibitors and fulvestrant, in late lines of therapy is poor with overall response rates (ORR) less than 10% and median progression free survival (mPFS) of 2-3 months. Elacestrant is a novel, nonsteroidal, oral SERD with marked antitumor activity documented in multiple in vivo pt derived xenograft models of BC, including those derived from heavily pretreated pts and those with ESR1 mut. Methods: RAD1901-005 is a multi-part phase 1 study of elacestrant with the primary objective to determine the maximum tolerated dose (MTD) and/or recommended phase 2 dose (RP2D). Secondary objectives are safety, tolerability, pharmacokinetics, and preliminary antitumor activity. Part A was dose escalation with 3+3 design (capsule; doses 200, 400 and 600 mg QD); Part B was safety expansion (capsule); Part C was expansion (tablet); Part D expansion (tablet) was added by amendment to study later line pts including prior CDK4/6 inhibitor (i) use (NCT02338349). Key eligibility criteria: advanced or metastatic (m) ER+, HER2- BC; postmenopausal status. For Parts A-C: ≤2 prior chemotherapy regimens (CT) for mBC and >6 mo ET with progression (PD). For Part D: ≤1 prior CT for mBC, ≥2 prior lines of ET including PD on fulvestrant, and CDK4/6i. We present updated and final results from the trial (all parts). Results: From April 2015 to March 2018, 57 pts were enrolled: Part A: 13, B: 20, C: 14, D: 10 (of 36 planned; enrollment was terminated due to change in regulatory strategy). MTD/RP2D was 400 mg QD. For all pts treated at 400 mg (n=50): stage IV 100%; visceral disease 70%; median prior lines of tx 3 (Part D: 4), including median of 1 prior line of CT and 3 prior lines of ET; prior CDK4/6i 52% (Part D: 100%); prior fulvestrant 50% (Part D: 100%); prior mTORi 26%. At baseline, 51% of pts had detectable ESR1 mut, including D538G, Y537S/N/C, L536H/P/R, S436P and E380Q. Among pts treated with 400 mg tablet (n=24), treatment-emergent adverse events in ≥20% were nausea, hypertriglyceridemia, hypophosphatemia, vomiting, dyspepsia, constipation, hypokalemia, fatigue, back pain, myalgia, headache, and urinary tract infection; the majority were grade 1 and 2. There were no treatment-related deaths. 13% of pts discontinued due to AEs. Antitumor activity is summarized in Table 1. There were 6 confirmed partial responses; median duration of response was 24.9 wk; median time to response was 8.2 wk. One pt with ESR1 mut with best response of SD remains on treatment at 3 yr. Conclusion: Elacestrant at the RP2D of 400 mg QD has an acceptable safety profile and demonstrated significant single-agent anti-tumor activity in heavily pretreated (mostly 4th line or greater) ER+, HER2- mBC pts. Activity was seen following prior fulvestrant, prior CDK4/6i, and in pts with ESR1 mut. The ORR of 19.4% and mPFS of 4.5 mo compare favorably with those reported for fulvestrant and AIs given in earlier treatment settings. Elacestrant monotherapy vs. standard of care ET monotherapy is currently being studied in ER+, HER2- mBC with 1 or 2 lines of prior tx including prior CDK4/6i, in the phase 3 “EMERALD” study (NCT03778931). Table 1. Efficacy OutcomesParts A-CPart DOverallORR, % (RECIST-evaluable pts) (n/N)27.3% (6/22)0% (0/9)19.4% (6/31)Clinical Benefit Rate, % (PR+SD ≥24 wk) (n/N)47.4% (18/38)22.2% (2/9)42.6% (20/47)mPFS (95% CI), mo, N=50 (ITT population)5.4 (3.7, 11.2)1.9 (1.8, 8.6)4.5 (1.9, 7.4) Citation Format: Virginia Kaklamani, Aditya Bardia, Sharon Wilks, Amy Weise, Donald Richards, Wael Harb, Cynthia Osborne, Robert Wesolowski, Meghan Karuturi, Paul Conkling, Rebecca Bagley, JungAh Jung, Teeru Bihani, Maureen Conlan, Peter Kabos. Final analysis of phase 1 study of elacestrant (RAD1901), a novel selective estrogen receptor degrader (SERD), in estrogen receptor positive (ER+), human epidermal growth factor receptor 2 negative (HER2-) advanced breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr PD7-07.

Background: ER+ metastatic breast cancer (mBC) remains a clinical challenge as most patients (pts) eventually have disease progression on treatment (tx). Multiple molecular mechanisms of resistance to standard-of-care drugs have been reported including mutations in ESR1 (mESR1) or PIK3CA (mPIK3CA); understanding how these affect response to subsequent tx is important. Elacestrant (RAD1901), an investigational oral selective estrogen receptor degrader (SERD), has demonstrated preclinical efficacy in pt-derived xenograft models of ER+ BC, including models harboring mESR1 and mPIK3CA. Elacestrant was evaluated in 2 phase 1 clinical trials (NCT02650817, NCT02338349) in postmenopausal women with ER+/HER2- mBC, including pts that had received multiple prior endocrine tx (median=3) and targeted tx, including CDK4/6 inhibitors (38%). Circulating tumor DNA (ctDNA) collected in these 2 trials was used to characterize the molecular features of this heavily pretreated population and correlate them with elacestrant response. Methods: ctDNA samples were collected at baseline (BL), on-tx (OT) and end-of-tx (EOT). BL samples were analyzed using the Guardant360® assay (Guardant Health) to detect genomic alterations in 73 relevant genes. Changes in BL mESR1 allele frequency of 12 single nucleotide variants (SNVs) in the ligand binding domain of ESR1 were assessed in paired OT and EOT ctDNA samples using the OncoBEAM™ platform (Sysmex Inostics). Response was assessed using RECIST v1.1. Results: Among 73 pts enrolled in these 2 trials, 57 had BL samples. At least 1 alteration was detected in 93% (n=53) of pt samples, with alterations detected in 52 of the 73 genes in the Guardant360® panel. The most frequently detected BL alterations were in ESR1 (47%) and PIK3CA (44%), with alterations in both genes observed in 21% of pts. At BL, 25% (14/57) of pt samples had >1 mESR1; the most commonly detected mESR1 were Y537S (56%), D538G (56%), and Y537N (26%). Following elacestrant tx, there was a decrease in mESR1 allele frequency in 100% of samples (11/11 mESR1 SNVs decreased OT in 9/9 pts). In paired EOT samples from pts lacking mESR1 at BL analyzed to date (N=23), 1 new mESR1 was detected in 1 pt. Among response-evaluable (RE) pts with mESR1 at BL (n=16), there were 4 partial responses (PR; 25%); clinical benefit rate (CBR) at 24 weeks (ie, stable disease + PR) in clinical benefit evaluable (CBE) pts was 52% (11/21); and median progression-free survival (mPFS) in intention-to-treat (ITT) pts was 8.6 mo. Among RE pts with mPIK3CA at BL (n=16), there were 2 PRs (13%); CBR at 24 weeks in CBE pts was 24% (5/21); and mPFS (ITT pts) was 1.9 mo. Conclusions: Relevant genomic alterations, especially in ESR1 and PI3KCA, were detected at BL in a significant proportion of heavily pretreated postmenopausal women with ER+/HER2- mBC enrolled in elacestrant phase 1 trials. Clinical benefit, including PR, was observed in pts with genomic alterations, including mESR1 and PIK3CA. Elacestrant monotherapy vs. standard of care endocrine tx is currently being studied in the phase 3 “EMERALD” study in ER+/HER2- mBC pts, including pts with mESR1, who have received 1 or 2 prior lines of endocrine tx and prior CDK4/6i (NCT03778931). Citation Format: Teeru Bihani, JungAh Jung, Hitisha K Patel, Aditya Bardia, Peter Kabos, Virginia Kaklamani, Agnes Jager, Philippe Aftimos, Sharon Wilks, Elisabeth de Vries, Wael Harb, Donald Richards, Amy Weise, Robert Wesolowski, Catharina CW Menke-van der Houven van Oordt, Paul Conkling, Patrick Neven, Maureen G Conlan. Genomic alterations detected by circulating tumor DNA and correlation with response to treatment with elacestrant, an oral selective estrogen receptor degrader, in phase 1 trials in postmenopausal women with ER+/HER2- advanced/metastatic breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-01-05.

BACKGROUND. Seribantumab (MM‐121) is a fully human IgG2 monoclonal antibody that binds to human epidermal growth factor receptor 3 (HER3/ErbB3) to block heregulin (HRG/NRG)‐mediated ErbB3 signaling and induce receptor downregulation. This open‐label, randomized phase 1/2 study evaluated safety and efficacy of seribantumab plus erlotinib in advanced non‐small cell lung cancer (NSCLC). Here, we report the activity of seribantumab plus erlotinib, versus erlotinib alone, in patients with EGFR wild‐type tumors and describe the potential predictive power of HRG. MATERIALS AND METHODS. Patients with EGFR wild‐type NSCLC were assigned randomly to receive seribantumab + erlotinib or erlotinib alone. Patients underwent pretreatment core needle biopsy and archived tumor samples were collected to support prespecified biomarker analyses. RESULTS. One hundred twenty‐nine patients received seribantumab + erlotinib (n = 85) or erlotinib alone (n = 44). Median estimated progression‐free survival (PFS) in the unselected intent‐to‐treat (ITT) population was 8.1 and 7.7 weeks in the experimental and control arm, respectively (hazard ratio [HR], 0.822; 95% confidence interval [CI], 0.37–1.828; p = 0.63), and median estimated overall survival was 27.3 and 40.3 weeks in the experimental and control arm, respectively (HR, 1.395; 95% CI, 0.846 to 2.301; p = .1898) In patients whose tumors had detectable HRG mRNA expression, treatment benefit was observed in the seribantumab + erlotinib combination (HR, 0.35; 95% CI, 0.16–0.76; p = .008). In contrast, in patients whose tumors were HRG negative, the HR was 2.15 (95% CI, 0.97–4.76; p = .059, HRG‐by‐treatment interaction, p value = .0016). CONCLUSION. The addition of seribantumab to erlotinib did not result in improved PFS in unselected patients. However, predefined retrospective exploratory analyses suggest that detectable HRG mRNA levels identified patients who might benefit from seribantumab. An ongoing clinical trial of seribantumab, in combination with docetaxel, is underway in patients with advanced NSCLC and high HRG mRNA expression (NCT02387216). IMPLICATIONS FOR PRACTICE. The poor prognosis of patients with non‐small cell lung cancer (NSCLC) underscores the need for more effective treatment options, highlighting the unmet medical need in this patient population. The results of this study show that a novel biomarker, heregulin, may help to identify patients with advanced NSCLC who could benefit from treatment with seribantumab. On the basis of the observed safety profile and promising clinical efficacy, a prospective, randomized, open‐label, international, multicenter phase II trial (SHERLOC, NCT02387216) is under way to investigate the efficacy and safety of seribantumab in combination with docetaxel in patients with heregulin‐positive advanced adenocarcinoma.

Purpose: Epithelial ovarian cancer (EOC) is a molecularly diverse disease. MEK inhibition targets tumors harboring MAPK pathway alterations and enhances paclitaxel-induced apoptosis in EOC. This phase Ib study evaluated the MEK inhibitor binimetinib combined with paclitaxel in patients with platinum-resistant EOC. Patients and Methods: Patients received intravenous weekly paclitaxel with oral binimetinib in three different administration schedules. Outcomes were assessed by RECIST and CGIC CA-125 response criteria. Tumor samples were analyzed using next-generation sequencing. Results: Thirty-four patients received ≥1 binimetinib dose. A 30-mg twice-a-day continuous or 45-mg twice-a-day intermittent binimetinib dose was deemed the recommended phase II dose (RP2D) in combination with 80 mg/m2 i.v. weekly paclitaxel. Rate of grade 3/4 adverse events was 65%. The best overall response rate was 18%—one complete (CR) and four partial responses (PR)—among 28 patients with RECIST-measurable disease. Eleven patients achieved stable disease (SD), yielding a clinical benefit rate (CR+PR+SD) of 57%. Response rates, per both RECIST and CA-125 criteria, were highest in the 45-mg twice-a-day continuous cohort and lowest in the 45-mg twice-a-day intermittent cohort. All four evaluable patients with MAPK pathway–altered tumors experienced clinical benefit. Conclusions: The combination of binimetinib and intravenous weekly paclitaxel was tolerable in this patient population. The RP2D of binimetinib in combination with paclitaxel was 30 mg twice a day as a continuous or 45 mg twice a day as an intermittent dose. Although response rates were modest, a higher clinical benefit rate was seen in patients harboring alterations affecting the MAPK pathway. Clin Cancer Res; 24(22); 5525–33. ©2018 AACR.

Background: Decitabine (DAC), a DNA methyltransferase 1 inhibitor/hypomethylating agent, is not readily orally bioavailable due to rapid clearance by cytidine deaminase in the gut/liver. This first-in-human pharmacokinetic/pharmacodynamic-guided dose-escalation study evaluated whether simultaneous oral administration with the novel cytidine deaminase inhibitor cedazuridine increases DAC bioavailability for myelodysplastic syndromes (MDS) therapy. Methods: In this phase 1 study, patients with MDS received escalating oral doses of DAC and cedazuridine. The primary objectives were to assess the safety of ASTX727, a combination of the two drugs, and to determine the dose of each drug needed to achieve a mean area under the curve (AUC) for DAC similar to that for iv DAC. Findings: Forty-four patients (43 evaluable) with previously treated or newly diagnosed MDS or chronic myelomonocytic leukemia were treated in five cohorts: cohorts 1-4 included six evaluable patients each; cohort 5 included 19 patients in a 13-patient expansion. Twenty patients (46%) had received prior hypomethylating agent therapy. Dose-dependent increases in DAC AUC and peak plasma concentration occurred with each cohort dose escalation. There was no evident increase in toxicity compared with that reported for iv DAC. Decitabine 30 or 40 mg with cedazuridine 100 mg produced mean day 5 DAC AUCs of 146 and 221 ng*h/mL, respectively, compared with a mean iv DAC AUC of 153-166 ng*h/mL. Long interspersed nuclear element-1 demethylation increased with dose. Thirteen patients (30%) had a clinical response, including five (12%) with a complete response, two with a marrow complete response, and six with hematologic improvement. Six patients remain on therapy. Interpretation: Oral ASTX727 emulated the pharmacokinetics of iv DAC, with a similar safety profile and dose-dependent demethylation. Clinical responses were similar to iv DAC treatment for 5 days. Funding: Astex Pharmaceuticals, Inc. and StandUp2Cancer. Declaration of Interest: MRS has received research support from Astex, Boehringer Ingelheim, Celgen, Gilead, Incyte, Millennium, Sunesis, and TG Therapeutics; has consulted for Astex, Celgene, Gilead, Incyte, Karyopharm, Millennium, Sunesis, and TG Therapeutics; and has equity in Karyopharm. OO has received research support from Astex. AbbVie, Agios, AstraZeneca, Celgene, CTI/Baxalta, Gilead, Incyte, Janssen, NS-Pharma, Oncotherapy, Sanofi, and S*Bio; has participated in advisory board meetings for AbbVie, Celgene, CTI/Baxalta, Dava Oncology, Incyte, Jazz, and Pfizer; and has received drug supply support from Pfizer. PCA has received research support from Astex. DPS has received research support from Celgene, H3 Biosciences, and Janssen; and has received personal fees from Janssen, Onconova, Sensei, and Takeda. AED, SF, and WH have nothing to declare. LCM has received research support from Jazz; has consulted for Incyte; has participated in a speakers bureau for Celgene; has participated in advisory board meetings for Novartis and TG Therapeutics; and has equity in Pfizer. HK has received research support from Astex, AbbVie, Agios, Amgen, Ariad, BMS, Cyclacel, Immunogen, Jazz, and Pfizer; has received honoraria from AbbVie, Agios, Amgen, Immongen, Orsinex, Pfizer, and Takeda; and has participated in advisory board meetings for Actinium. JL, AO, and MA are employees of Astex. GG-M has research support and honoraria from Astex/Otsuka. Ethical Approval: All patients provided written informed consent. The protocol was approved by the institutional review board at each participating institution.

Endocrine therapy is an important treatment option for women with hormone receptor–positive (HR+) advanced breast cancer (ABC), yet many tumors are either intrinsically resistant or develop resistance to these therapies. Treatment of patients with ABC presenting with visceral metastases, which is associated with a poor prognosis, is also problematic. There is an unmet need for effective treatments for this patient population. Although chemotherapy is commonly perceived to be more effective than endocrine therapy in managing visceral metastases, patients who are not in visceral crisis might benefit from endocrine therapy, avoiding chemotherapy-associated toxicities that might affect quality of life. To improve outcomes, several targeted therapies are being investigated in combination with endocrine therapy for patients with endocrine-resistant, HR+ ABC. Although available data have considered patients with HR+ ABC as a whole, there are promising data from a prespecified analysis of a Phase III study of everolimus (Afinitor®), a mammalian target of rapamycin (mTOR) inhibitor, in combination with exemestane (Aromasin®) in patients with visceral disease progressing after nonsteroidal aromatase inhibitor therapy. In this review, challenges and treatment options for management of HR+ ABC with visceral disease, including consideration of therapeutic approaches undergoing clinical investigation, will be assessed., Video abstract

Background Enadenotucirev (EnAd) is a tumor-selective chimeric Ad11/Ad3 group B oncolytic adenovirus. Following IV dosing of EnAd, viral delivery has been shown in various carcinomas together with CD8+ T-cells. These data provide a rationale for combination of EnAd with nivolumab (anti-PD-1). Methods EnAd was escalated in patients with metastatic epithelial tumors in a 3 + 3 design. Subjects received increasing dose levels and/or cycles of EnAd followed by up to 8 cycles of nivolumab. The primary objective of the dose escalation phase was to evaluate safety and recommend a dose for expansion. Secondary endpoints include ORR and OS. Results 31 patients with metastatic colorectal cancer (mCRC), with median 4 prior lines of therapy, were treated. Of these, 22 are confirmed MSS. EnAd dosing ranged between 1x1012 and 3x1012 virus particles infused IV 3 times weekly for one or two weeks, followed by nivolumab. Flu-like symptoms were reported in the majority of patients following EnAd administration. Adverse events of infusion reaction and hypoxia meeting DLT criteria were reported on C2D1 administration of EnAd requiring increased prophylaxis. Grade 4 acute renal injury was reported in one subject, with renal biopsy showing membranoproliferative glomerulonephritis (GN) indicative of immune complex deposition. Additional monitoring revealed changes suggestive of post-infectious GN in ∼25% of patients after 3-4 weeks of EnAd dosing. These were asymptomatic and resolved without treatment. Kinetics, cytokines and anti-drug antibody responses were consistent with known profiles for both agents. As of 03May2019, median OS is reported as 12.6 mo and median PFS is 2.8 mo. There were no objective responses, but PD markers in 6/8 matched biopsy samples show evidence of increased CD8 T cell infiltration and upregulation of markers of T cell activation. Stable disease exceeding 4 mo was seen in 6/31 (4/22 MSS). Conclusions The combination of EnAd and nivolumab has a manageable toxicity profile supporting further investigation in study expansion. Favourable OS outcome in a highly refractory CRC population was noted and may suggest delayed immune antitumor activity in this population. Clinical trial identification 2017-001231-39. Legal entity responsible for the study PsiOxus Therapeutics Ltd. Funding PsiOxus Therapeutics Ltd; Bristol-Myers Squibb. Disclosure P. Basciano: Full / Part-time employment: Bristol-Myers Squibb. R. Brown: Shareholder / Stockholder / Stock options, Full / Part-time employment: PsiOxus Therapeutics Ltds. O. Arogundade: Full / Part-time employment: PsiOxus Therapeutics Ltds. C. Cox: Full / Part-time employment: PsiOxus Therapeutics Ltds. G. Di Genova: Full / Part-time employment: PsiOxus Therapeutics Ltds. D. Krige: Full / Part-time employment: PsiOxus Therapeutics Ltds. H. McElwaine-Johnn: Leadership role, Shareholder / Stockholder / Stock options, Full / Part-time employment: PsiOxus Therapeutics Ltds. All other authors have declared no conflicts of interest.

TPS3158 Background: VT1021 is a cyclic pentapeptide that functions as a potent inducer of thrombospondin-1 (Tsp-1) expression in the tumor microenvironment (TME). By triggering the production of Tsp-1, VT1021 reprograms the TME from one that is immune-suppressive and tumor-promoting, to one that activates the adaptive immune system and is tumor-inhibiting. Tsp-1 reprograms the TME to: (i) induce apoptosis in tumor cells that express CD36 on their cell surface, (ii) convert macrophages from M2 to M1 polarization, which promotes phagocytosis and blunts immunosuppression and (iii) inhibit angiogenesis. Preclinical studies have shown robust anti-tumor activities of VT1021 in animal models of ovarian, pancreatic and breast cancer, including complete tumor regression and reprogramming of the immune TME. These observations led to the initiation of the first-in-human study of VT1021. Methods: This study is a first-in-human, Phase 1, open-label, multicenter, dose escalation (Part 1) study with dose expansion (Part 2) in advanced solid tumors. The primary objectives are to assess the safety and tolerability of VT1021, to assess dose-limiting toxicities (DLT), and to determine the maximum tolerated dose (MTD) and the recommended Phase 2 dose (RP2D). Secondary objectives include the evaluation of pharmacokinetics (PK) and pharmacodynamic (PD) effects of VT1021 in tumor and tumor microenvironment, and assessment of preliminary antitumor activity. VT1021 is administered intravenously twice weekly. DLTs will be assessed in the first cycle (Days 1-28) of the dose escalation cohort and are defined as grade 3 adverse events related to VT1021. In Part 1 of the study, 24-30 patients will be enrolled to determine the MTD and RP2D for expansion. In Part 2 of the study, 80-100 patients will be enrolled, grouped into cohorts based on disease subtypes (ovarian, pancreatic, Triple-negative breast cancers, and glioblastoma). Blood samples and biopsy samples from patients will be collected to assess PK properties and PD responses systemically as well as in the TME. No formal statistical hypothesis testing will be conducted in this study. This study is currently open for enrollment in the US. Clinical trial information: NCT03364400.

101 Background: Viagenpumatucel-L (HS-110) is an allogeneic cellular vaccine derived from a human lung adenocarcinoma (AD) cell line transfected with the gp96-Ig fusion protein. DURGA is a multi-cohort study evaluating the combination of HS-110 and immune checkpoint blockers (ICBs) in patients with advanced NSCLC. Here we report the initial two cohorts with the combination of HS-110 and nivolumab. Methods: Patients (pts) with previously treated NSCLC received 1 X 107 HS-110 cells weekly for the first 18 weeks and nivolumab 3 mg/kg or 240 mg every 2 weeks until intolerable toxicity or tumor progression. Tissue was tested at baseline for PD-L1 expression (≥ 1% or < 1%) and tumor infiltrating lymphocytes (TILs). TIL high was defined by more than 10% CD8+ lymphocytes in the tumor stroma. Pts in cohort A had never received, and pts in cohort B had received, prior ICBs. The primary objectives were safety and objective response rates (ORR). Results: As of the August 2018 data cut-off, there were 43 pts enrolled into cohort A (40 AD and 3 squamous cell carcinoma [SCC]) and 18 pts in cohort B (15 AD and 3 SCC). In cohort A, 14 pts (32.6%) were TIL high, 13 (30.2%) TIL low and 16 (37.2%) TIL unknown. ORR, disease control rate (DCR), median progression-free survival (PFS) and 1 year PFS were 18.6%, 48.8%, 1.9 months and 23.9% respectively in cohort A, with median follow up of 432 days. ORR, DCR, and PFS were 22%, 50% and 2.2 months respectively in cohort B, with median follow up of 43 days. The median overall survival (mOS) was not reached in either cohort. In cohort A, TIL low at baseline was associated with increased mOS compared to TIL high (not reached vs 13.8 months, hazard ratio [HR] 0.23, 95% CI 0.068-0.81, p = 0.04). There were no differences in mOS according to PD-L1 status in cohort A (p = 0.82). 57 (93%) pts experienced at least one adverse event (AE), of which 39 (64%) were grade 1 or 2. The most common AEs were fatigue (31%), cough and diarrhea (19.7% each). There were 2 grade 5 AEs (3.3%) caused by pulmonary embolism and tumor progression, neither considered to be treatment related. Conclusions: The combination of HS-110 and nivolumab is safe with encouraging preliminary efficacy data. The study is ongoing and additional populations are being explored. Clinical trial information: NCT02439450.

Purpose Vintafolide (EC145) is a folic acid–desacetylvinblastine conjugate that binds to the folate receptor (FR), which is expressed on the majority of epithelial ovarian cancers. This randomized phase II trial evaluated vintafolide combined with pegylated liposomal doxorubicin (PLD) compared with PLD alone. The utility of an FR-targeted imaging agent, 99mTc-etarfolatide (EC20), in selecting patients likely to benefit from vintafolide was also examined. Patients and Methods Women with recurrent platinum-resistant ovarian cancer who had undergone ≤ two prior cytotoxic regimens were randomly assigned at a 2:1 ratio to PLD (50 mg/m2 intravenously [IV] once every 28 days) with or without vintafolide (2.5 mg IV three times per week during weeks 1 and 3). Etarfolatide scanning was optional. The primary objective was to compare progression-free survival (PFS) between the groups. Results The intent-to-treat population comprised 149 patients. Median PFS was 5.0 and 2.7 months for the vintafolide plus PLD and PLD-alone arms, respectively (hazard ratio [HR], 0.63; 95% CI, 0.41 to 0.96; P = .031). The greatest benefit was observed in patients with 100% of lesions positive for FR, with median PFS of 5.5 compared with 1.5 months for PLD alone (HR, 0.38; 95% CI, 0.17 to 0.85; P = .013). The group of patients with FR-positive disease (10% to 90%) experienced some PFS improvement (HR, 0.873), whereas patients with disease that did not express FR experienced no PFS benefit (HR, 1.806). Conclusion Vintafolide plus PLD is the first combination to demonstrate an improvement over standard therapy in a randomized trial of patients with platinum-resistant ovarian cancer. Etarfolatide can identify patients likely to benefit from vintafolide.

B-cell receptor (BCR) signaling plays a key role in the pathogenesis of B-cell malignancies, mediating the survival and proliferation of malignant B cells.1,2 Clinical studies have shown that Bruton’s tyrosine kinase (BTK) inhibitors are well tolerated, with promising clinical activity. Ibrutinib has shown 30-month progression-free survival (PFS) of 69% in relapsed chronic lymphocytic leukemia (CLL) patients,3–5 and has substantial activity in mantle cell lymphoma and activated B-cell-type diffuse large B-cell lymphoma.6,7 CC-292 is a highly selective oral small-molecule inhibitor that binds covalently and irreversibly to the same cysteine 481 in BTK as ibrutinib, inhibiting its signaling.8 We report here the results of a phase I study of CC-292 in patients with relapsed/refractory (R/R) CLL/small lymphocytic lymphoma (SLL), B-cell non-Hodgkin lymphoma (B-NHL), and Waldenstrom macroglobulinemia (WM). A total of 113 patients received continuous dosing with CC-292 in 28-day cycles at doses ranging from 125 mg to 1000 mg once daily, and 375 mg and 500 mg twice daily, continuing into dose-expansion cohorts of 750 mg once daily and a preliminary recommended phase II dose (RP2D)-expansion cohort of 500 mg twice daily. Four patients experienced dose-limiting toxicity (DLT) but only one in any treatment cohort. The most frequent grade 3–4 adverse events (AEs) were neutropenia (16%) and thrombocytopenia (8%). The most common non-hematologic treatment-emergent AEs (TEAEs) of any grade were diarrhea (68%) and fatigue (45%). Twice-daily administration of CC-292 was instituted to improve sustained BTK occupancy, and, in fact, did result in more than 90% BTK receptor occupancy at both the 4- and 24-h post-dose time points. Efficacy in the CLL/SLL population (n=84) showed that overall response rate (ORR) in patients receiving twice-daily dosing was 53%; an additional 10% had partial response with lymphocytosis (PR-L). CC-292 was, therefore, well tolerated and achieved high nodal and PR rates in relapsed CLL/SLL patients, but showed less durability than other BTK inhibitors.

Background: Neratinib (HKI-272) is an irreversible pan-ErbB receptor tyrosine kinase inhibitor that has shown antitumor activity in patients with ErbB2+ breast cancer. Capecitabine has demonstrated efficacy and tolerability in combination with lapatinib, a reversible dual ErbB1/ErbB2 kinase inhibitor, in patients with ErbB2+ advanced breast cancer. The current study evaluated the safety and clinical activity of neratinib in combination with capecitabine. Methods: In part 1 of this open-label, phase 1/2 study, the maximum tolerated dose (MTD) of neratinib in combination with capecitabine was determined in adults with advanced solid tumors. Part 2 of the study further evaluated the safety and clinical activity of neratinib plus capecitabine at the MTD in adults with confirmed ErbB2+ metastatic or locally advanced breast cancer (ECOG Performance Status of 0–2). Eligible patients had received prior taxane treatment and ≥1 prior trastuzumab-containing regimen for ≥6 weeks for metastatic or locally advanced disease. The primary endpoint of part 2 was objective response rate (ORR); tumor responses were assessed by investigators using modified RECIST version 1.0 guidelines every 6 weeks. Results: In part 1 (n = 33), the MTD was determined to be neratinib 240 mg/day plus capecitabine 750 mg/m2 twice daily on Days 1 to 14 of each 21-day cycle. In part 2, as of April 2011, 72 female patients (median age of 52 years [range, 33–79 years]) with ErbB2+ breast cancer were enrolled and treated at the MTD; 7 patients had prior lapatinib exposure and all had prior trastuzumab and taxane exposure. As of the snapshot date, 56% of patients at the MTD were still participating in the study. The most common drug-related adverse events (AEs) in part 2 were diarrhea (89%), palmar-plantar erythrodysesthesia (57%), nausea (33%), vomiting (26%), and decreased appetite (22%). Grade 3/4 drug-related AEs in ≥5% of patients were diarrhea (25%) and palmar-plantar erythrodysesthesia (13%). Eight patients withdrew from part 2 due to AEs, including 4 who withdrew due to diarrhea. Dose interruptions of neratinib and capecitabine, respectively, due to AEs were required by 19 and 29 patients; dose reductions due to AEs were required by 8 and 22 patients. As of June 2010 (interim analysis), 22 patients were evaluable for efficacy in part 2 of the study. Of these 22 patients, 11 achieved a partial response for an ORR of 50%. An additional 2 patients maintained stable disease for ≥24 weeks, resulting in a clinical benefit rate of 59%, and 8 patients had stable disease for Conclusions: The results of this study indicate that neratinib combined with capecitabine is tolerable and has promising antitumor activity in patients with ErbB2+ metastatic or locally advanced breast cancer pretreated with trastuzumab. This study supports further evaluation of this combination in ErbB2+ breast cancer. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-12-09.

Introduction: Bevacizumab is approved in combination with chemotherapy as first-line treatment for non-small cell lung cancer (NSCLC). Preclinical data suggest that enzastaurin and bevacizumab may have complementary effects in inhibiting angiogenesis. Methods: Eligibility criteria: ≥18 years of age, chemonaive, stage IIIB/IV nonsquamous NSCLC, and Eastern Cooperative Oncology Group performance status 0 to 1. Patients were randomized to placebo or enzastaurin 500 mg orally daily (after a loading dose), plus pemetrexed 500 mg/m 2 , carboplatin area under the curve 6, and bevacizumab 15 mg/kg, intravenously, every 21 days for four cycles. Patients without progression received maintenance therapy with bevacizumab and placebo or enzastaurin. The primary objective was progression-free survival (PFS). Planned sample size was 90 patients, one-sided alpha of 0.20, with two interim analyses: one for safety and the second for futility, with a PFS hazard ratio of 0.8857. Results: Forty patients were randomized. No unique safety concerns were noted at the first interim analysis. The early stopping rule for futility was met at the second interim analysis. Median PFS was 3.5 months and 4.3 months (hazard ratio: 1.04, 95% confidence interval: 0.49–2.21), and response rates were 20% and 30% ( p = 0.462) for enzastaurin and placebo, respectively. Grade 3 or 4 toxicity was similar between the two arms. Two patients died on study because of respiratory arrest and pulmonary embolism. An additional patient died of sepsis secondary to a gastrointestinal perforation >30 days after study treatment discontinuation. Conclusions: Enzastaurin does not improve efficacy when combined with pemetrexed, carboplatin, and bevacizumab. This combination does not warrant further study in NSCLC.

Introduction: BET proteins are key epigenetic regulators of transcription whose inhibition may suppress expression of genes that promote oncogenic pathways. INCB054329, a potent small-molecule inhibitor of BET proteins, inhibited growth of model cell lines derived from solid and hematologic tumors in vitro and in vivo. We report safety, pharmacokinetics (PK), pharmacodynamics (Pd), and efficacy from a phase 1/2 study of INCB054329 in pts with advanced malignancies (NCT02431260). Methods: Eligible adults with relapsed and/or refractory advanced malignancies, ≥1 prior therapy, and ECOG performance status ≤1 received oral INCB054329 in 21-d cycles until withdrawal criteria were met. Dose escalation followed a 3+3 design; PK and Pd were assessed after single and multiple doses. Primary endpoints were safety and tolerability. Results: As of the data cut-off, 54 pts (solid tumors, n=50; lymphoma, n=4) were enrolled at doses ranging from 15-30 mg QD to 15-25 mg BID, including intermittent regimens (5 d on/2 d off, 4 d on/3 d off, 7 d on/7 d off). One dose-limiting toxicity (DLT) occurred at 30 mg QD (grade [G] 3 thrombocytopenia). Although a maximum tolerated dose was not identified, doses >20 mg BID were not tolerated beyond cycle 1. At the nontolerated dose of 22.5 mg BID, G3/4 thrombocytopenia was observed in 2 out of 3 pts in cycle 2. Therefore, 20 mg BID was selected as the starting dose for further exploration in a planned intrapatient dose titration cohort. 41 pts (76%) had treatment-related treatment-emergent adverse events (TEAEs), most frequently nausea (n=17 [31%]), fatigue (n=15 [28%]), thrombocytopenia (n=14 [26%]), and decreased appetite (n=13 [24%]). Treatment-related G ≥3 TEAEs were thrombocytopenia (n=5 [9%]); neutropenia (n=2 [4%]); anemia, elevated aspartate aminotransferase, hyponatremia, and hypophosphatemia (n=1 [2%] each). Three pts (6%) had 4 treatment-related serious TEAEs (thrombocytopenia, n=3; anemia, n=1). Treatment-related TEAEs led to dose interruption in 13 pts (primarily due to thrombocytopenia [8/13]) and dose reduction in 1 pt (neutropenia). Two fatal TEAEs occurred (septic shock, n=1; respiratory failure; n=1), neither treatment-related. Median INCB054329 exposure was 8.5 wk (range, 1.1-69.7). Mean terminal elimination half-life of INCB054329 was short (~2-3 h), and PK was characterized by high interpatient variability. Exposure correlated with thrombocytopenia on an individual basis; PK associated closely with activity in a Pd assay of c-Myc expression. Among pts with solid tumors, 1 pt (2%) with NSCLC had a partial response (61% decrease in target lesion per RECIST v1.1; the pt soon came off study treatment due to a diagnosis of a new malignancy [CRC]), 3 pts (6%) had stable disease (SD) ≥6 mo (12, 9, and 6 mo), 14 pts (28%) had SD Citation Format: Gerald Falchook, Moshe Talpaz, Monica Mita, Russ Szmulewitz, Sarina Piha-Paul, Wael Harb, Daniel Morgensztern, Jason Kaplan, Pamela Munster, Robert F. Cornell, Fred Zheng, Swamy Yeleswaram, Gongfu Zhou, Ryan Cassaday. Phase 1/2 study of INCB054329, a bromodomain and extraterminal (BET) protein inhibitor, in patients (pts) with advanced malignancies [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr A093.

Carfilzomib, a proteasome inhibitor, is approved in the United States as a single agent, and in combination with dexamethasone or lenalidomide/dexamethasone (KRd) for relapsed or refractory multiple myeloma (MM). Under the single-agent and KRd approvals, carfilzomib is administered as a 10-minute IV infusion on days 1, 2, 8, 9, 15, and 16 of 28-day cycles (20 mg/m(2) [cycle 1, days 1-2]; 27 mg/m(2) thereafter). This multicenter, single-arm, phase 1/2 study, Community Harmonized Assessment of Myeloma Patients via an Integrated Oncology Network-1 (CHAMPION-1), evaluated once-weekly carfilzomib with dexamethasone in relapsed, or relapsed and refractory MM (1-3 prior therapies). Patients received carfilzomib (30-minute IV infusion) on days 1, 8, and 15 of 28-day cycles. The phase 1 portion used a 3 + 3 dose-escalation scheme to determine the maximum tolerated dose (MTD) of carfilzomib. During phase 2, patients received carfilzomib on the same schedule at the MTD. Patients received dexamethasone (40 mg) on days 1, 8, 15, and 22; dexamethasone was omitted on day 22 for cycles 9+. A total of 116 patients were enrolled. The MTD was 70 mg/m(2), and 104 patients (phase 1/2) received carfilzomib 70 mg/m(2) At 70 mg/m(2), the median number of prior regimens was 1; and 52% were bortezomib-refractory. At 70 mg/m(2), the most common grade ≥3 adverse events were fatigue (11%) and hypertension (7%). Overall response rate at 70 mg/m(2) was 77%. Median progression-free survival was 12.6 months. These findings merit additional evaluation of the once-weekly dosing regimen. This trial was registered at www.clinicaltrials.gov as #NCT01677858.

The progressive deterioration in nutrition status frequently seen in cancer patients is often referred to as cancer cachexia. Unlike starvation, in which fat stores from adipose are depleted and protein is spared from skeletal muscle, neither fat nor protein is spared in cachexia. Cachexia affects nearly half of cancer patients, causing the clinical manifestations of anorexia, muscle wasting, weight loss, early satiety, fatigue, and impaired immune response. Cachexia does not only impede the response to chemotherapy but also is a major cause of morbidity and mortality. According to clinical studies, increasing caloric intake does not necessarily reverse cachexia. The pathophysiology of cachexia involves more complex mechanisms than simply caloric deficiency. The process appears to be mediated by circulating catabolic factors, either secreted by the tumor alone or in concert with host-derived factors, such as tumor necrosis factor-alpha (TNF-alpha), interleukins (IL-1 and IL-6), interferon (IFN-y), and leukemia inhibitory factor (LIF). The successful reversal of this process will require in-depth knowledge of the mechanisms involved, which will then enable the development of effective pharmacologic interventions that may not only improve quality of life, but more importantly, improve survival among cancer patients.

TPS3115 Background: EnAd is a tumor-selective chimeric Ad11/Ad3 group B oncolytic adenovirus developed using directed evolution. Phase I clinical studies have identified a well-tolerated systemic dose and regimen for EnAd monotherapy. EnAd shows a high level of selective replication and cell killing for a broad range of carcinoma cell lines with little replication in normal and non-carcinoma cells. Previous studies have shown that after systemic administration there is significant uptake and replication of EnAd in various carcinomas associated with improved CD8+ T-cell tumor infiltration. These data provide the rationale for combination of EnAd with the checkpoint inhibitor (CPI), nivolumab (anti-PD-1 antibody) to potentially enhance the response to nivolumab. This is a phase I study in subjects with metastatic or advanced carcinoma. The study design has a dose escalation stage, followed by a dose expansion stage which will evaluate the ability to improve responses in tumors normally non-responsive to CPI and also to evaluate the ability to detect meaningful responses in PDL1 negative tumors that are less responsive to CPI. Methods: The dose escalation phase consists of 5 cohorts of patients with metastatic or advanced epithelial tumors in a standard "3 + 3" design. Subjects will receive increasing dose levels and/or cycles of EnAd followed by a q3w regimen of nivolumab (360mg). EnAd treatment cycles comprise 3 intravenous (IV) infusions on Days 1, 3 and 5. Nivolumab is administered as an IV infusion given every 3 weeks starting on Day 15 and continuing for up to 8 treatment cycles. The Dose Expansion phase will investigate the combination of EnAd and nivolumab in expanded cohorts of colorectal cancer, urothelial cell carcinoma, squamous cell carcinoma of the head & neck, and non-small cell lung cancer patients. The primary objectives are to establish the MTD of EnAd and nivolumab combination, to evaluate the safety and to recommend doses for future studies. Secondary endpoints include overall response, duration of response and progression free survival, assessed according to RECIST Version 1.1 and irRECIST Version 1. Enrollment to cohorts 3 & 4 began in January 2017. Clinical trial information: NCT02636036.

2576 Background: The folate receptor (FR) is highly expressed in a variety of cancers including adenocarcinoma of the lung, but is expressed at low levels in most normal tissues, making it a potential target for therapeutic intervention. EC1456 is an FR-targeted small molecule drug conjugate (SMDC) consisting of folic acid chemically attached through a bio-releasable linker system to a potent microtubule inhibitor, tubulysin B hydrazide (TubBH). EC1456 binds to, and is endocytosed by the FR-expressing cancer cell to deliver TubBH. Following endocytosis, the FR recycles back to the membrane surface every 18-24 hours. Therefore alternative EC1456 schedules will be evaluated for safety, pharmacokinetics, and therapeutic benefit. Methods: Part A (dose escalation) is being evaluated in unselected patients (pts) with advanced solid tumors. 4 schedules (3-week cycle) are being evaluated: BIW (twice weekly); QW (once weekly); CWD (continuously weekly); QIW (four times a week). The primary objective of Part A is to determine the RP2 dose and schedule of EC1456. Part B (expansion) will confirm the MTD and RP2 dose and evaluate efficacy of EC1456 in 99mTc-etarfolatide-selected NSCLC patients in up to three schedules. Results: 74 Part A pts are evaluable for toxicity. Median age is 68 (range: 26-88); 53 pts are female. Toxicities are primarily Grade (Gr) 1 and 2. Common treatment-related adverse events (TRAE) are gastrointestinal, fatigue, metabolic changes, alopecia, and headache. 5 Gr 3 DLTs have been observed: infusion reaction (4.5 mg/m2 QW), headache (10.0 mg/m2 QW), and abdominal pain (7.5 mg/m2 BIW, 12.5 mg/m2 QW and 10.0 mg/m2CWD). TRAEs are summarized in the table for each schedule. Durable stable disease of 12 wks or longer has been observed in 12 pts (6 BIW and 6 QW). Conclusions: All Part A EC1456 schedules have been well tolerated. RP2 dose for BIW is 6.0 mg/m2 and QW is 12.5 mg/m2; dose escalation is ongoing for CWD and QIW. Early signs of efficacy in an unselected pt population may be suggested by durable stable disease. Safety and efficacy evaluation in the 99mTc-etarfolatide-selected NSCLC population (Part B) is ongoing. Clinical trial information: NCT01999738. [Table: see text]

TPS3110 Background: CSF1, which signals via CSF1R, regulates tumor-associated macrophages and myeloid-derived suppressor cells, both critical drivers of immune escape in the tumor microenvironment. ARRY-382 is a highly selective, oral inhibitor of the CSF1R intracellular tyrosine kinase. The first-in-human study of ARRY-382 monotherapy identified the maximum tolerated dose (MTD) of 400 mg QD, with biologic activity at doses ≥200 mg QD (Bendell JC et al. Mol Cancer Ther. 2013;12:A252). Preclinical data supports combining a PD-1 inhibitor with a CSF1R inhibitor (Zhu Y et al. Cancer Res. 2014;74:5057-69). This study is designed to evaluate ARRY-382 in combination with pembro, a potent and highly selective humanized monoclonal antibody that targets PD-1. Methods: This is an open-label, multicenter, phase 1b/2 study (NCT02880371) to determine the MTD and/or recommended phase 2 dose (RP2D) of ARRY-382 + pembro and to evaluate the activity of the combination in select indications. In phase 1b (Part A), the primary objective is to identify the MTD/RP2D. Up to 18 pts with select advanced solid tumors (Part A) will be enrolled in 2 successive cohorts evaluating ARRY-382 at doses of 200 mg QD and 400 mg QD, respectively, in combination with pembro 2 mg/kg Q3W. Once the MTD/RP2D has been determined in phase 1b, phase 2 will concurrently evaluate the combination in up to 20 pts with advanced unresectable/metastatic melanoma (Part B) and in up to 33 pts with PD-L1-positive (tumor proportion score ≥50) non-small cell lung cancer (NSCLC) (Part C). The primary objective of Part B is to assess the pharmacodynamics and antitumor activity of ARRY-382 + pembro in pts with advanced unresectable/metastatic melanoma, and the endpoints include effects of treatment on circulating growth factors and cytokines, markers of bone resorption, and objective response rate (ORR). The primary objective of Part C is to assess the efficacy of ARRY-382 + pembro in pts with PD-L1–positive NSCLC (Part C). The primary endpoint is ORR. Immune-related response rate and safety will be evaluated in all pts in the study. Clinical trial information: NCT02880371.

4531 Background: Vesigenurtacel-L (HS-410) is a vaccine comprised of an allogeneic cell line, selected for high expression from a series of bladder tumor antigens, and transfected with gp96-Ig. Cell-secreted gp96-Ig delivers these cell-derived antigens to a recipient's own antigen presenting cells, activating CD8+ cytotoxic T cells. Here we present the secondary immune outcomes from a randomized Phase 2 trial with HS-410 in combination with BCG in NMIBC. Trial ID NCT02010203. Methods: 78 patients with intermediate- (n = 5) or high-risk (n = 73) NMIBC who are either BCG-naïve or recurrent, with or without carcinoma in situ (CIS), were enrolled 1:1:1 to one of two doses of HS-410 (either 106 or 107cells/dose) or placebo in combination with 6 weeks of induction BCG, followed by 6 more weeks of HS-410 in the induction phase. Maintenance treatment consisted of 3-weekly treatments at the following timepoints: 3 mo., 6 mo., 12 mo. Concurrently, 16 patients (1 int. risk, 15 high-risk) were enrolled in an open-label monotherapy HS-410 arm for patients who did not receive BCG. The primary endpoint was 1-year RFS. Secondary immune evaluations include ELISPOT, tumor IHC, tumor antigen profiling, flow cytometry, urine cytokine analysis, and T cell receptor sequencing. Results: HS-410 treatment was well tolerated; AE profiles were similar across the treatment arms. HS-410 antigen expression showed prominent overlap with patient tumors. IFNγ ELISPOT assay demonstrated a high baseline response to HS-410; responses to overlapping peptide pools of HS-410 derived antigens defined immune responders (doubling of IFNγ-secreting cells). IHC demonstrated that ~60% of NMIBC patient tumor biopsies were TIL negative at baseline (n = 84), but that only ~15% of tumor biopsies were TIL negative post treatment (n = 40). Thus, TIL status may be used to define a responder and non-responder population to HS-410. Conclusions: Vesigenurtacel-L is well-tolerated, and immunologic responses consistent with vaccine mechanism of action may correlate with efficacy and suggest future biomarkers. Vesigenurtacel-L warrants further investigation as a potential treatment for NMIBC. Clinical trial information: NCT02010203.

319 Background: Vesigenurtacel-L (HS-410) is a vaccine comprised of an allogeneic cell line, selected for high expression from a series of bladder tumor antigens, and transfected with gp96-Ig. Cell-secreted gp96-Ig delivers these cell-derived antigens to a recipient's own antigen presenting cells, activating CD8+ cytotoxic T cells. Here we present the secondary immune outcomes from a randomized Phase 2 trial with HS-410 in combination with BCG in NMIBC. Trial ID NCT02010203. Methods: 78 patients with intermediate- (n=5) or high-risk (n=73) NMIBC who are either BCG-naïve or recurrent, with or without carcinoma in situ (CIS), were enrolled 1:1:1 to one of two doses of HS-410 (either 106 or 107cells/dose) or placebo in combination with 6 weeks of induction BCG, followed by 6 more weeks of HS-410 in the induction phase. Maintenance treatment consisted of 3-weekly treatments at the following timepoints: 3 mo., 6 mo., 12 mo. Concurrently, 16 patients (1 int. risk, 15 high-risk) were enrolled in an open-label monotherapy HS-410 arm for patients who did not receive BCG. The primary endpoint was 1-year RFS. Secondary immune evaluations include ELISPOT, tumor IHC, tumor antigen profiling, flow cytometry, urine cytokine analysis, and T cell receptor sequencing. Results: HS-410 treatment was well tolerated; AE profiles were similar across the treatment arms. HS-410 antigen expression showed prominent overlap with patient tumors. IFNγ ELISPOT assay demonstrated a high baseline response to HS-410; responses to overlapping peptide pools of HS-410 derived antigens defined immune responders (doubling of IFNγ-secreting cells). IHC demonstrated that ~60% of NMIBC patient tumor biopsies were TIL negative at baseline (n=84), but that only ~15% of tumor biopsies were TIL negative post treatment (n=40). Thus, TIL status may be further used to define a responder and non-responder population to HS-410. Conclusions: Vesigenurtacel-L is well-tolerated, and immunologic responses consistent with vaccine mechanism of action may correlate with efficacy and suggest future biomarkers. Vesigenurtacel-L warrants further investigation as a potential treatment for NMIBC. Clinical trial information: NCT02010203.

Introduction: Effective treatments for hormone-receptor-positive (HR +) breast cancer (BC) following relapse/progression on nonsteroidal aromatase inhibitor (NSAI) therapy are needed. Initial Breast Cancer Trials of OraL EveROlimus-2 (BOLERO-2) trial data demonstrated that everolimus and exemestane significantly prolonged progression-free survival (PFS) versus placebo plus exemestane alone in this patient population. Methods: BOLERO-2 is a phase 3, double-blind, randomized, international trial comparing everolimus (10 mg/day) plus exemestane (25 mg/day) versus placebo plus exemestane in postmenopausal women with HR+ advanced BC with recurrence/progression during or after NSAIs. The primary endpoint was PFS by local investigator review, and was confirmed by independent central radiology review. Overall survival, response rate, and clinical benefit rate were secondary endpoints. Results: Final study results with median 18-month follow-up show that median PFS remained significantly longer with everolimus plus exemestane versus placebo plus exemestane [investigator review: 7.8 versus 3.2 months, respectively; hazard ratio = 0.45 (95% confidence interval 0.38-0.54); log-rank P < 0.0001; central review: 11.0 versus 4.1 months, respectively; hazard ratio = 0.38 (95% confidence interval 0.31-0.48); log-rank P < 0.0001] in the overall population and in all prospectively defined subgroups, including patients with visceral metastases, patients with recurrence during or within 12 months of completion of adjuvant therapy, and irrespective of age. The incidence and severity of adverse events were consistent with those reported at the interim analysis and in other everolimus trials. Conclusion: The addition of everolimus to exemestane markedly prolonged PFS in patients with HR+ advanced BC with disease recurrence/progression following prior NSAIs. These results further support the use of everolimus plus exemestane in this patient population. ClinicalTrials.gov, SCOPUS: ar.j, info:eu-repo/semantics/published

Panobinostat is a histone deacetylase inhibitor that has shown synergistic preclinical anti-myeloma activity when combined with other agents, recently exhibiting synergy with the alkylating agent melphalan (Sanchez et al., Leuk Res 35(3):373–379, 2011). This phase 1/2 trial investigated the safety and efficacy of panobinostat in combination with melphalan for relapsed/refractory multiple myeloma patients. There were four different trial treatment schedules due to tolerability issues, with the final treatment schedule (treatment schedule D) consisting of panobinostat (15 or 20 mg) and melphalan (0.05 or 0.10 mg/kg), both administered on days 1, 3, and 5 of a 28-day cycle. A total of 40 patients were enrolled; 3 in treatment schedule A, 9 in schedule B, 7 in schedule C, and finally 21 schedule D. Patients had been treated with a median of four regimens (range, 1–16) and two prior bortezomib-containing regimens (range, 0–9). Maximum-tolerated dose was established at 20 mg panobinostat and 0.05 mg/kg melphalan in treatment schedule D. Overall, 3 patients (7.5 %) achieved ≥partial response (two very good PRs and one PR) while 23 exhibited stable disease and 14 showed progressive disease. All three responders were enrolled in cohort 2 of treatment schedule B (panobinostat 20 mg thrice weekly continuously with melphalan 0.05 mg/kg on days 1, 3, and 5). Neutropenia and thrombocytopenia were common, with 30.8 and 23.1 % of patients exhibiting ≥grade 3, respectively. Panobinostat + melphalan appears to have tolerability issues in a dosing regimen capable of producing a response. Care must be taken to balance tolerability and efficacy with this combination.