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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.

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

Introduction Myelofibrosis (MF) typically presents with constitutional symptoms, splenomegaly, and anemia with the degree of anemia and transfusion dependency being among the most important predictors of poor overall survival (OS). Momelotinib (MMB) is a differentiated JAK1, JAK2 inhibitor with potent activity against ACVR1/ALK2, a critical regulator of hepcidin production and iron metabolism. MMB has demonstrated clinical activity against all 3 of these hallmark features of MF in the SIMPLIFY Ph 3 studies including SIMPLIFY-1 (S1) in the JAK inhibitor (JAKi) naïve setting compared directly to ruxolitinib (RUX) and in the previously JAKi experienced patients (SIMPLIFY-2 [S2]) in comparison to best available therapy (BAT) which was predominately RUX. MMB has also demonstrated robust OS in the JAKi naïve population (S1) and JAKi experienced population (S2) (Verstovsek et al. ASH 2020). Critically, patients randomized to MMB who maintain or achieve transfusion independence (TI) by Week 24 (W24) had better OS, further suggesting that MMB's anemia benefits positively impact long term outcomes in patients with MF (Mesa et al. EHA 2021). Increased hepcidin and ferritin are associated with dysregulated iron metabolism and inflammation, both of which have previously been shown to be strong negative prognostic factors for OS in patients with MF at the time of first referral (Pardanani et al. 2013). A Ph 2 translational biology study previously demonstrated MMB acutely and chronically suppresses elevated levels of hepcidin and restores iron homeostasis in transfusion dependent patients who achieve a W24 TI-response (TI-R; Oh et al. 2020). Interestingly, several baseline factors, such as hepcidin, ferritin and CRP from this study suggested a potential threshold of W24 TI-R for patients treated with MMB, warranting further exploration. Methods Based on the findings from the Ph 2 translational biology study we retrospectively analyzed the relationship between serum ferritin, hepcidin and CRP and the W24 TI-R rates for patients randomized to MMB and RUX in S1 using generalized linear regression models where the degree of predictiveness measured by the interaction between treatment and the biomarkers as continuous or categorical variables using various cutoffs were examined. These findings were then independently confirmed in the previously RUX treated patients from S2. Results These analyses identified pre-treatment serum ferritin level as the most predictive biomarker for the treatment effect of MMB vs RUX on W24 TI-R rate in S1. The TI-R treatment effect of MMB vs RUX was significantly greater (p=0.0051) in the ≥90ng/mL cohort (62% vs 35% respectively, with response ratio [RR]=1.8) than in the Data also demonstrated a significant increase in serum ferritin for RUX vs MMB at W24 vs baseline (RUX mean ferritin change +226.1ng/mL vs MMB +13.8ng/mL, p=0.0003), irrespective of baseline ferritin. Conclusion Ferritin is a well-established and easily measured clinical biomarker that is associated with both iron metabolism and uncontrolled inflammation. Prior analyses demonstrate patients randomized to MMB who achieve a W24 TI-R have increased OS compared to non-TI responders. These new analyses expand on these findings, demonstrating that the MMB vs RUX treatment effect is greater in baseline serum ferritin ≥90ng/mL vs Figure 1 Figure 1. Disclosures Oh: Abbvie: Membership on an entity's Board of Directors or advisory committees; Blueprint Medicines: Membership on an entity's Board of Directors or advisory committees; Celgene Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Constellation: Membership on an entity's Board of Directors or advisory committees; CTI Biopharma: Membership on an entity's Board of Directors or advisory committees; Disc Medicine: Membership on an entity's Board of Directors or advisory committees; Geron: Membership on an entity's Board of Directors or advisory committees; Incyte: Membership on an entity's Board of Directors or advisory committees; Kartos Therapeutics: Membership on an entity's Board of Directors or advisory committees; PharamaEssentia: Membership on an entity's Board of Directors or advisory committees; Sierra Oncology: Membership on an entity's Board of Directors or advisory committees. Gerds: PharmaEssentia Corporation: Consultancy; CTI BioPharma: Research Funding; Sierra Oncology: Consultancy; AbbVie: Consultancy; Celgene/Bristol Myers Squibb: Consultancy; Constellation: Consultancy; Novartis: Consultancy. Mesa: CTI: Research Funding; Pharma: Consultancy; Incyte Corporation: Consultancy, Research Funding; Abbvie: Research Funding; AOP: Consultancy; Constellation Pharmaceuticals: Consultancy, Research Funding; Samus: Research Funding; Celgene: Research Funding; Gilead: Research Funding; Promedior: Research Funding; La Jolla Pharma: Consultancy; Sierra Oncology: Consultancy, Research Funding; CTI: Research Funding; Novartis: Consultancy; Genentech: Research Funding. Gupta: Pfizer: Consultancy; Roche: Consultancy; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Constellation Pharma: Consultancy, Honoraria; BMS-Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Honoraria; Sierra Oncology: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Incyte: Honoraria, Research Funding. Huang: Sierra Oncology: Current Employment; BioMarin: Ended employment in the past 24 months. Ro: Sierra Oncology: Current Employment; BeiGene: Ended employment in the past 24 months. Strouse: Sierra Oncology: Current Employment. Klencke: Sierra Oncology: Current Employment, Current equity holder in publicly-traded company. Verstovsek: Blueprint Medicines Corp: Research Funding; Roche: Research Funding; PharmaEssentia: Research Funding; NS Pharma: Research Funding; Ital Pharma: Research Funding; Protagonist Therapeutics: Research Funding; Incyte Corporation: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; CTI BioPharma: Research Funding; Gilead: Research Funding; Genentech: Research Funding; Sierra Oncology: Consultancy, Research Funding; Promedior: Research Funding; AstraZeneca: Research Funding; Novartis: Consultancy, Research Funding; Constellation: Consultancy; Pragmatist: Consultancy.

Background: Momelotinib (MMB) is a potent, orally bioavailable, small-molecule inhibitor of JAK1, JAK2, and ACVR1 with demonstrable clinical activity against the three hallmark features of myelofibrosis (MF), namely anemia, constitutional symptoms, and splenomegaly, across the continuum of intermediate-/high-risk MF patients whether JAKi-naive or previously JAKi-treated. Objective: To characterize the long-term safety of MMB in comparison to ruxolitinib (RUX). Methods: SIMPLIFY-1 was a double-blind, randomized, study of MMB vs RUX in intermediate-/high-risk JAKi-naive patients with MF (n=215 MMB, 217 RUX). SIMPLIFY-2 (S2) was a randomized study of MMB vs best available therapy (BAT; RUX in 88% of patients) in prior RUX-treated patients with hematological toxicity (n=104 MMB, 52 BAT). Randomized treatment (RT) for 24 weeks was followed by open-label MMB extended treatment in both studies. Data from RT were compared, and further long-term data were analyzed from 550 subjects receiving MMB, including 336 subjects on MMB for ≥48 weeks and 148 for ≥144 weeks. Results: Despite treatment duration exceeding 3.5 years for >90 subjects, the incidence of grade 3/4 hematological toxicity was very low. During the S1 RT period, grade 3/4 anemia occurred in only 6.1% of MMB subjects compared with -4-fold higher rate (22.7%) for RUX. Dose reductions due to thrombocytopenia were also 4-fold higher for RUX (24.5%) than MMB (6.1%). Subjects randomized to MMB in S1 experienced a rapid, sustained increase in hemoglobin, in contrast to significant hemoglobin decrease on RUX. Following crossover to MMB from RUX, hemoglobin increased rapidly to above baseline. Platelet values were also significantly higher compared to RUX. Similarly, in S2, hemoglobin and platelet values were maintained or improved on MMB. Importantly, no new safety signals and no cumulative toxicity were observed during extended MMB dosing. Rates of peripheral neuropathy remained low. Conclusions: MMB displays very favorable long-term tolerability, including an absence of significant rates of high-grade hematological and other toxicities or evidence of cumulative toxicity, consistent with its differentiated pharmacological and clinical profile. Notably, subjects switching from RUX also experienced favorable tolerability, despite their previous therapy.

e19039 Background: Momelotinib (MMB) is a potent JAK1, JAK2 and ACVR1 inhibitor with clinical activity against the hallmark features of myelofibrosis (MF), namely anemia, constitutional symptoms and splenomegaly, across the continuum of JAKi naïve or previously JAKi treated intermediate/high risk MF patients as demonstrated in the previously conducted Phase 3 SIMPLIFY-1 & -2 clinical trials (S1, S2). S1 was conducted in JAKi-naïve patients with MF (n = 432) double-blind randomized 1:1 to MMB or ruxolitinib (RUX). MMB demonstrated a statistically non-inferior splenic response rate (SRR) to RUX at the W24 landmark analysis in S1 but did not meet significance for total symptom score (TSS) response. Low SRR and TSS response was observed for RUX in patients with low platelets, while MMB elicited consistent SRR and TSS response across the platelet subsets, comparable to the response in the ITT. Transfusion independence (TI) at W24 was higher for MMB vs RUX patients across all PLT strata. Methods: Progressive anemia is a common occurrence in MF with nearly all MF patients requiring transfusions as their disease advances. Given the prognostic importance of Hgb and transfusion status in MF patients including evidence that achieving or maintaining transfusion independence by Week 24 with momelotinib is associated with improved OS in S1 and S2, we expanded the previously reported retrospective platelet subset analysis to explore the W24 TI response rates for MMB and RUX randomized patients in S1 by baseline Hgb and PLT levels and transfusion status. Results: The data presented here suggest that the prognostically-important W24 TI rate was substantively higher in anemic patients receiving MMB versus RUX, irrespective of the degree of anemia. MMB is also more effective relative to RUX in achieving or maintaining TI in JAKi naïve patients irrespective of baseline PLT count or baseline transfusion status. Conclusions: Together with data suggesting that TI response at W24 with momelotinib is associated with a survival advantage, these data further support the potential TI benefits of inhibiting ACVR1 in addition to JAK1 and JAK2 with MMB in MF patients. Clinical trial information: NCT01969838, NCT02101268. [Table: see text]

e19040 Background: Clinical trials investigating JAK1/JAK2 inhibitors for myelofibrosis (MF) subjects have measured symptom improvement as a minimum 50% reduction in total symptom score (TSS) at the end of a 24-week treatment period. This landmark analysis is based on post-baseline score changes from Weeks 21 (W21) to 24 and requires vastly different absolute TSS improvements for patients with very high or low baseline (BL) TSS to reach responder status. A phase 3 clinical study, SIMPLIFY-1, randomized 432 intermediate and high risk JAK inhibitor (JAKi) naive MF patients 1:1 to momelotinib (MMB) or ruxolitinib (RUX). Non-inferiority on the MPN-SAF TSS response rate endpoint at W24 was not met (MMB: 28% vs RUX: 42%); however, improvement in each of the 7 TSS items was similar for MMB vs RUX. To understand the discrepancy, we applied item analysis and mixed effect models for repeated measures (MMRM) to SIMPLIFY-1. Methods: Analyses were conducted in the intention-to-treat (ITT) population and in a symptomatic subset (selected as subjects with BL TSS ≥ 10). The distributions of TSS items were examined at BL and shift in scores at W24 (health state shifts) were assessed. GEE models were used to estimate item-level odds ratios using multiple predictive imputations for missing data. MMRM compared mean change in TSS from BL to W24 using data from all visits. The meaningful change threshold (MCT) was determined using Patient Global Impression of Change. Results: BL scores across items were heterogenous in the MMB and RUX groups; the proportion of subjects with no or mild symptoms (0–3 on a 0-10 point scale) ranged from 44% (tiredness) to 81% (itching). Distributions of BL scores were different across arms with 6 out of 7 items in the MMB arm reporting more severe or very severe symptoms (scores of 7-10) at BL. Despite the imbalance in BL scores, item-level health state shifts showed similar improvements for MMB and RUX. Categorical responder analysis showed no significant differences on any items. Odds ratios for each between-group comparison ranged from 0.74 to 1.20. MMRM mean TSS change at W24 was 6.35 (MMB) vs 7.87 (RUX) in the ITT and 8.80 (MMB) vs 10.46 (RUX) in the symptomatic subset. Mean TSS were near the within-subject MCT of 8 points in the ITT and exceeded the MCT in the symptomatic subset. The between-group difference was 1.52 (95% CI: (0.196, 2.847)) in the ITT and 1.67 (95% CI: -0.134, 3.468) in the symptomatic subset. Conclusions: Comparable item health state shifts at W24 and similar improvements in mean TSS as shown by MMRM, with a minimal between-group difference of 1.52 on the 70 point scale in context of an 8-point MCT suggest MMB provides clinically relevant and comparable symptom improvements to RUX; these analyses require further validation in independent data sets. Imbalance in BL symptom scores in MMB subjects may have contributed to the inability to demonstrate non-inferiority in TSS response rate at W24. Clinical trial information: NCT01969838.

Purpose The antibody-drug conjugate trastuzumab-DM1 (T-DM1) combines the biologic activity of trastuzumab with targeted delivery of a potent antimicrotubule agent, DM1, to human epidermal growth factor receptor 2 (HER2) –overexpressing cancer cells. Based on results from a phase I study that showed T-DM1 was well tolerated at the maximum-tolerated dose of 3.6 mg/kg every 3 weeks, with evidence of efficacy, in patients with HER2-positive metastatic breast cancer (MBC) who were previously treated with trastuzumab, we conducted a phase II study to further define the safety and efficacy of T-DM1 in this patient population. Patients and Methods This report describes a single-arm phase II study (TDM4258g) that assessed efficacy and safety of intravenous T-DM1 (3.6 mg/kg every 3 weeks) in patients with HER2-positive MBC who had tumor progression after prior treatment with HER2-directed therapy and who had received prior chemotherapy. Results With a follow-up of ≥ 12 months among 112 treated patients, the objective response rate by independent assessment was 25.9% (95% CI, 18.4% to 34.4%). Median duration of response was not reached as a result of insufficient events (lower limit of 95% CI, 6.2 months), and median progression-free survival time was 4.6 months (95% CI, 3.9 to 8.6 months). The response rates were higher among patients with confirmed HER2-positive tumors (immunohistochemistry 3+ or fluorescent in situ hybridization positive) by retrospective central testing (n = 74). Higher response rates were also observed in patients whose tumors expressed ≥ median HER2 levels by quantitative reverse transcriptase polymerase chain reaction for HER2 expression, compared with patients who had less than median HER2 levels. T-DM1 was well tolerated with no dose-limiting cardiotoxicity. Most adverse events (AEs) were grade 1 or 2; the most frequent grade ≥ 3 AEs were hypokalemia (8.9%), thrombocytopenia (8.0%), and fatigue (4.5%). Conclusion T-DM1 has robust single-agent activity in patients with heavily pretreated, HER2-positive MBC and is well tolerated at the recommended phase II dose.

Erlotinib, an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, is active in glioblastoma. We evaluated erlotinib efficacy in patients with first-relapse glioblastoma and assessed whether response was related to EGFR amplification and/or concomitant use of enzyme-inducing antiepileptic drugs (EIAEDs) in a phase II open-label study of glioblastoma patients in first relapse. Patients took erlotinib daily until progression. Starting dose was 150 mg for patients not taking EIAEDs and 300 mg for patients taking EIAEDs. Tumors were radiographically assessed every 8 weeks. Response was evaluated by investigators and confirmed by an independent radiology facility (IRF). The primary efficacy outcome was the objective response (OR) rate, according to the modified WHO criteria. Enrollment (n = 48) was terminated after a planned interim analysis due to an insufficient number of responses. The IRF confirmed 1 complete and 2 partial responses (PRs), for an OR rate of 6.3% (95% confidence interval [CI]: 1.7-17.0). Investigators determined 1 complete response and 3 PRs, median response duration of 7.0 months, 6-month progression-free survival (PFS) of 20% (95% CI: 10.0-32.4), and median survival of 9.7 months (95% CI: 5.9-11.6). Outcomes were not related to EGFR amplification or EIAED status. Diarrhea and rash were the most common adverse events (AEs); 23% of patients experienced grade 3-4 drug-related AEs. Despite the limited number of responses, 6-month PFS and median survival reached or exceeded the previously reported values for patients undergoing chemotherapy for recurrent glioblastoma. EGFR amplification was not associated with erlotinib activity. Given the large CIs and nonrandomized nature of the study, results should be interpreted cautiously.

BACKGROUND 131I-Metaiodobenzylguanidine (131I-MIBG) can be used systemically to treat malignant pheochromocytoma. To improve outcome, the authors used higher levels of activity of 131I-MIBG than previously reported. The authors reported the response rates and toxicity levels in patients with malignant pheochromocytoma or paraganglioma who were treated with high-dose 131I-MIBG. METHODS Following debulking surgery and stem cell harvest, 12 patients with malignant pheochromocytoma or paraganglioma were treated with 131I-MIBG. Five had received previous external beam radiation and/or chemotherapy. The median single treatment dose was 800 mCi (37 gigabecquerels; range, 386–866 mCi) or 11.5 mCi/kg (range, 5.6–18.3 mCi/kg). The median cumulative dose was 1015 mCi (range, 386–1690 mCi). RESULTS Three patients had a complete response, two of whom had soft tissue and skeletal metastases. Their median follow-up was 45 months (range, 23–101 months). Seven patients had a partial response (PR), with a median follow-up 43 months (range, 6–47 months). Two patients without a response died with progressive disease (PD) and 2 patients with an initial PR died of PD at 13 and 11 months, respectively. Grade 3 thrombocytopenia occurred after 79% (15 of 19) of treatments had been administered. Grade 3 and 4 neutropenia followed 53% (10 of 19) and 19% (4 of 19) of treatments, respectively. One patient required stem cell infusion, and one developed primary ovarian failure. CONCLUSIONS The single and cumulative doses of 131I-MIBG were approximately 2–3.5 times higher than those used at other centers. Unlike previous reports, two patients with both skeletal and soft tissue metastases had a complete response. Hematologic toxicity was significant but tolerable. High-dose 131I-MIBG may lead to long-term survival in patients with malignant pheochromocytoma. Cancer 2003;98:239–48. © 2003 American Cancer Society. DOI 10.1002/cncr.11518

TPS2607 Background: SRA737 is a highly selective, orally bioavailable small molecule inhibitor of Checkpoint kinase 1 (Chk1), a key cell cycle checkpoint and central regulator of the DNA Damage Response (DDR) network. In cancer cells, replication stress induced by genomic alterations in oncogenes (eg, MYC and RAS) combined with loss of function in tumor suppressors (eg, TP53 and ATM) results in persistent DNA damage and genomic instability. Targeted inhibition of components of the DDR network such as Chk1 by SRA737 may be synthetically lethal to cancer cells and have utility as a monotherapy in a range of tumor indications. SRA737 is currently being investigated in two Phase 1 trials in patients with advanced cancer. We now describe the Phase 1 multicenter, dose-escalation, monotherapy study of SRA737 (NCT02797964). Methods: Up to 40 patients with advanced cancer will receive oral SRA737 administered daily on a 28-day schedule. For dose-escalation, an accelerated titration design with 100% dose escalation and single patient cohorts is allowed until Grade 2 related toxicity is observed, followed by a rolling-6 design. Dose expansion will include 6 patients with any solid tumor treated at the recommended Phase 2 dose (RP2D). Eligibility criteria include WHO performance status of 0-1 and ≤ 3 prior lines of cytotoxic chemotherapy for metastatic disease. Primary objectives are to assess the safety profile of monotherapy SRA737 and to establish a RP2D. The PK profile and PD biomarkers will be investigated. The study was opened to enrollment in mid-2016. An amendment, which includes the addition of indication specific expansion cohorts of subjects with genetically-defined tumors known to have Chk1-sensitizing aberrations such as gene mutations and amplifications/deletions, has been submitted and is pending regulatory review while enrollment continues. At the Annual Meeting, the amended design will be described. The dose and schedule identified in this trial will inform the design and conduct of Phase 2 studies of SRA737 as a single agent and in combination with other targeted or immunomodulatory agents. Clinical trial information: NCT02797964.

TPS2613 Background: SRA737 is a highly selective, orally bioavailable small molecule inhibitor of Checkpoint kinase 1 (Chk1), a key cell cycle checkpoint and central regulator of the DNA Damage Response (DDR) network. In cancer cells, replication stress induced by genomic alterations in oncogenes (eg, MYC and RAS) combined with loss of function in tumor suppressors (eg, TP53 and ATM) results in persistent DNA damage and genomic instability. Targeted inhibition of components of the DDR network such as Chk1 by SRA737 may be synthetically lethal to cancer cells. Chk1 is also believed to facilitate tumor cell resistance to chemotherapy or radiation-induced DNA damage and the combination of SRA737 with these standards-of-care may provide synergistic antitumor activity. SRA737 is being investigated in two Phase 1 trials in patients with advanced cancer. We now describe the Phase 1 multicenter, dose-escalation study of SRA737 in combination with gemcitabine/cisplatin (GC) or gemcitabine (G) alone (NCT02797977). Methods: Up to 70 patients will receive escalating doses of SRA737+GC in Stage 1 or SRA737+G in Stage 2 until a recommended Phase 2 dose (RP2D) is established, followed by expansion cohorts. Patients will receive a single SRA737 PK run-in dose followed by Gem on D1 and 8, Cis on D1, SRA737 on D2, 3, 9 and 10 of each 21-d cycle or Gem on D1, 8 and 15, SRA737 on D2, 3, 9, 10, 16, 17 of each 28-d cycle. Eligibility criteria include WHO performance status of 0-1 and ≤ 3 prior lines of cytotoxic chemotherapy for metastatic disease. Primary objectives are to assess the safety profile of SRA737 combination therapy and to establish a RP2D. The PK profile and PD biomarkers (eg, phosphorylation of Chk1 at Ser296, Ser345 and γH2AX foci in PBMCs and tumor tissue) will be explored. The study was opened to enrollment in mid-2016. An amendment, which includes the addition of an indication specific expansion cohort of subjects with genetically-defined tumors known to have Chk1-sensitizing aberrations (eg, gene mutations and amplifications/deletions), has been submitted and is pending regulatory review while enrollment continues. At the Annual Meeting, the amended design will be described. Clinical trial information: NCT02797977.

Design: A selection of primary and transformed cell types were evaluated for their susceptibility to infection with human herpesvirus 8 (HHV-8)/Kaposi's sarcoma-associated herpesvirus. Methods: Sources of HHV-8 included Kaposi's sarcoma lesion punch biopsies that were either cocultured directly with target cells or that were first cocultured with human lymphocytes to derive HHV-8-containing fluids that were inoculated onto target cells. HHV-8 was also obtained from primary effusion lymphoma-derived cell lines. Techniques to detect infection included the PCR, immunofluorescence assays and in situ hybridization. Results: Susceptible cells included human umbilical cord blood mononuclear cells (UCMC), adult CD19 B cells, macrophages and certain endothelial cells of human and animal origin, including some that are transformed with human papilloma virus type 16 E6 and E7 genes. The infection of lymphocytes did not yield established lymphoblastoid cell lines (LCL) and virus infection persisted for only 4-7 days. However, long-term HHV-8 infection of UCMC could be achieved by coinfection with Epstein-Barr virus. HHV-8 could also infect UCMC LCL recently derived by Epstein-Barr virus transformation, but long-established LCL could not be infected with HHV-8. Conclusions: These data provide further biological evidence in cell culture for the limited cellular host range of HHV-8 to CD19 B cells, macrophages, and certain endothelial cells.

TPS7577Background: PNT2258, a liposomal encapsulated DNA interference (DNAi) oligonucleotide nanoparticle targeting the BCL2 oncogene, has demonstrated single agent activity with notable durability...

Background Carfilzomib is a next-generation proteasome inhibitor with single-agent activity in patients with relapsed and refractory multiple myeloma (R/R MM). In PX-171-003-A1, a single-arm phase 2 study of carfilzomib monotherapy in heavily pretreated patients, the overall response rate was 23.7%, 37% of patients achieved ≥ minimal response and median overall survival (OS) was 15.6 months. Based on this study, carfilzomib was recently approved by the US Food and Drug Administration for the treatment of R/R MM. Herein we describe the trial design and rationale for a phase 3 randomized study, FOCUS (CarFilzOmib for AdvanCed Refractory MUltiple Myeloma European Study), being conducted to compare OS after treatment with single-agent carfilzomib to best supportive care (BSC) regimen in R/R MM. Methods Patients must have received ≥3 prior regimens, must be responsive to at least 1 line of therapy, and be refractory to their most recent therapy. Eligible patients are randomized 1:1 to receive either carfilzomib (28-day cycles at 20 mg/m2 IV on Days 1–2 of Cycle 1, escalating to 27 mg/m2 IV on Days 8, 9, 15, and 16 and continuing at 27 mg/m2 through Cycle 9 and Days 1, 2, 15, and 16 ≥ Cycle 10) or an active BSC regimen (corticosteroid treatment of prednisolone 30 mg, dexamethasone 6 mg, or equivalent every other day with optional cyclophosphamide 50 mg PO once daily). Patients will continue treatment until disease progression, unacceptable toxicity, or treatment discontinuation and will then enter long-term follow-up for survival. The primary endpoint is OS and secondary endpoints include progression-free survival, overall response rate, and safety. Disease assessments will be determined according to the International Myeloma Working Group Uniform Response Criteria with minimal response per European Blood and Marrow Transplantation Group criteria. Conclusions This phase 3 trial will provide more rigorous data for carfilzomib, as this is the first carfilzomib study with OS as the primary endpoint and will not be confounded by crossover and will provide more robust secondary response and safety results that will add to the data set from prior phase 2 studies. FOCUS will facilitate regulatory approvals around the world and expand treatment options for patients with R/R MM. Trial registration EudraCT No. 2009-016840-38; NCT01302392.

Trastuzumab emtansine (T-DM1) is a HER2-targeted antibody-drug conjugate in development for treatment of HER2-positive cancers. T-DM1 has been tested as a single agent in a phase I and 2 phase II studies of patients with heavily pretreated metastatic breast cancer (MBC), with the maximum tolerated dose established at 3.6 mg/kg intravenously for every-3-week dosing. The authors present results from the population pharmacokinetics analysis for T-DM1. Population pharmacokinetics for T-DM1 were characterized using a clinical database of 273 patients from the 3 studies. Pharmacokinetics was best described by a linear 2-compartment model. Population estimates (interindividual variability [IIV]) for pharmacokinetic parameters were clearance, 0.7 L/d (21.0%); central compartment volume (V(c)), 3.33 L (13.2%); peripheral compartment volume (V(p)), 0.89 L (50.4%); and intercompartmental clearance, 0.78 L/d. Body weight, albumin, tumor burden, and aspartate aminotransferase levels were identified as statistically significant covariates accounting for interindividual variability in T-DM1 pharmacokinetics, with body weight having a greater effect on IIV of clearance and V(c) than other covariates. T-DM1 exposure was relatively consistent across the weight range following body weight-based dosing. This analysis suggests no further T-DM1 dose adjustments are necessary in heavily pretreated patients with MBC.

PurposeTo determine whether therapy with a DNA methyltransferase inhibitor is effective in achieving demethylation and gene re-expression in tumor DNA in patients.MethodsBiopsy specimens were obtained from patients with Epstein-Barr virus-associated tumors, enrolled on a clinical trial of 5-azacitidine, within 72 hours of the conclusion of the last infusion of the first cycle of therapy, and compared to pretreatment specimens. Methylation-specific polymerase chain reaction, bisulfite genomic sequencing, and immunohistochemistry were used to assess demethylation and gene re-expression.ResultsSubstantial degrees of demethylation were detected in all latent and lytic Epstein-Barr virus promoters examined. Immunohistochemistry suggested activation of a previously silent viral antigen expression in one instance.ConclusionPharmacologic reversal of dense CpG methylation in tumor tissue can be achieved in patients.

Although not yet included in the Centers for Disease Control definition of AIDS, anal cancer clearly occurs more commonly in HIV-infected patients. An effective screening program for those groups who are at highest risk might be expected to impact rates of anal cancer just as significantly as did cervical Pap screening programs for the incidence of cervical cancer. Despite a relatively low rate of progression from AIN to invasive cancer, the scope of the problem is enormous based on the prevalence of anal HPV infection and the size of the HIV-infected, at-risk population. Thus, the potential benefits of screening, detection, and the development of more effective therapy also are enormous. Currently, therapeutic HPV vaccines for AIN represent an exciting avenue of research in HPV-related anogenital disease. Invasive anal cancer and HSIL (which is believed to be the precursor lesion) are expected to become increasingly important health problems for both HIV-infected men and women as their life expectancy lengthens. Although HAART may have improved the ability of many to tolerate CMT, it appears that toxicity of this therapy continues to be a problem for a proportion of HIV-infected subjects. The acute side effects present specific challenges to the clinician and patient, have an immediate impact on the patient's plan of care and dose intensity of the treatment, and ultimately may impact the outcome of the planned treatment. Late toxicity may influence the long-term quality of life. Small patient numbers, variable radiation therapy doses, limited information about viral load, and a potential confounding effect of higher CD4+ levels make it difficult to draw any conclusions about the effect of HAART on anal cancer outcome. Large, prospective studies will be required before solid conclusions about the impact of various factors on anal cancer prognosis and outcome can be drawn.

High-grade dysplasia induced by high-risk types of human papillomavirus (HPV) precedes invasive cancer in anal squamous epithelium just as it does in the cervix. A therapeutic HPV vaccine strategy as a potential treatment for anal dysplasia was tested in a standard Phase I dose escalation trial. The primary objective was to evaluate the safety of the agent; additional study aims were to evaluate the histological response, immune response, and effect on anal HPV-16 infection. Each subject was treated with four i.m. injections of 50-400 microg of ZYC101 at 3-week intervals. ZYC101 is composed of plasmid DNA encapsulated in biodegradable polymer microparticles. The plasmid DNA encodes for multiple HLA-A2-restricted epitopes derived from the HPV-16 E7 protein, one of two HPV oncoproteins consistently expressed in neoplastic cells. Fifty-six potential anal dysplasia subjects were screened to identify 12 eligible subjects with HPV-16 anal infection and a HLA-A2 haplotype. The investigational agent was well tolerated in all subjects at all dose levels tested. Three subjects experienced partial histological responses, including one of three subjects receiving the 200-microg dose and two subjects at the 400-microg dose level. Using a direct Elispot, 10 of 12 subjects demonstrated increased immune response to the peptide epitopes encoded within ZYC101; each continued to show elevated immune responses 6 months after the initiation of therapy. These results support the continued investigation of a therapeutic vaccination strategy for anal dysplasia.

To assess the outcome and tolerance of HIV-positive patients with anal cancer to standard therapy based on their pretreatment CD4 count.Between 1991 and 1997, 17 HIV-positive patients with anal cancer and documented pretreatment CD4 counts were treated at the University of California, San Francisco or its affiliated hospitals with either concurrent chemotherapy and radiation or radiation alone. The outcome and complications of treatment were correlated with the patients' pretreatment CD4 count.Disease for all 9 patients with pretreatment CD4 countsor = 200 was controlled with chemoradiation. Although four required a treatment break of 2 weeks because of toxicity, none required hospitalization. Of the 8 patients with pretreatment CD4 counts200, 4 experienced decreased counts, intractable diarrhea, or moist desquamation requiring hospitalization. Additionally, 4 of these 8 ultimately required a colostomy either for a therapy-related complication or for salvage. Nevertheless, 6/7 in this group who received concurrent chemotherapy and radiation had their disease controlled, whereas the patient treated with radiation alone failed and required a colostomy for salvage.Patients with CD4or = 200 had excellent disease control with acceptable morbidity. Patients with CD4200 had markedly increased morbidity; however, disease was ultimately controlled in 7/8 patients.

The mortality and morbidity burden of Non-Hodgkin's lymphoma (NHL) is increasing within the human immunodeficiency virus- (HIV-) infected population. Recent improvements in HIV management has meant overall reductions in deaths, especially those due to opportunistic infections, and while the outcome of HIV-related NHL may now be somewhat less grim, the incidence remains high and outcome poor. The median survival of those with HIV-related NHL is only approximately 7 months, although those with high CD4 lymphocyte counts seem to do somewhat better. Improved management of the underlying HIV infection, more effective infusional chemotherapy regimens, moderately effective second line regimens, and new investigational approaches all offer promising hope that improvements will soon be seen for the treatment of HIV-related systemic NHL. Immunotherapy, monoclonal antibodies, and adoptive immunotherapy targeting Epstein Barr virus (EBV) all represent novel experimental treatment approaches that are becoming possible based on our increased understanding of the pathogenesis of HIV-related lymphoma. Primary central nervous system lymphoma (PCNSL) in HIV patients has declined in incidence and there now is a rapid, less invasive diagnostic test. The presence of EBV DNA in the cerebral spinal fluid of HIV patients with focal brain lesions strongly suggests a diagnosis of PCNSL. Unfortunately, this disease remains difficult to treat in such an immunocompromised patient population. Further work is needed in order to prevent and effectively manage these diseases.

1003 Background: The antibody-drug conjugate T-DM1 combines the biological activity of trastuzumab with targeted delivery of an anti-microtubule agent (DM1) to HER-2-expressing cancer cells. This analysis examines correlation of response to T-DM1 with HER-2 status, as assessed by fluorescent in situ hybridization (FISH), immunohistochemistry (IHC), mRNA quantitative real-time polymerase chain reaction (qRT-PCR), and enzyme-linked immunosorbent assay (ELISA) (HER-2 extracellular domain [ECD]), for pts enrolled in TDM4258g, a phase II study of T-DM1 in pts with MBC. Methods: TDM4258g is an open-label, single-arm study of T-DM1 administered at 3.6 mg/kg IV q3w. Pts had progressed on HER-2-directed therapy and received chemotherapy in the metastatic setting and were HER-2 + based on local testing. Archival tissue (paraffin block or >7 unstained tumor slides) was collected for retrospective central laboratory testing. HER-2 DNA amplification was determined by FISH, and protein levels by IHC. qRT-PCR for HER-2 was performed on extracted RNA; baseline HER-2 ECD ELISA was performed on pt sera. HER-2 data for each pt were compared with pt's best response. Results: As of August 29, 2008, 112 pts had enrolled; 107 were efficacy-evaluable pts with median 4.4 mos follow-up. There were 42/107 (39.3%) partial responses (PR) (investigator assessment). Of 86 pts centrally tested, 64 (74.4%) were confirmed HER-2+ (FISH+ and/or IHC 3+), with 32/64 (50%) PR. Of 76 pts tested by both FISH and IHC, 15/76 (19.7%) were confirmed HER-2- (FISH- and IHC 2+/1/0), with 2/15 (13.3%) PR. In HER-2+ pts, response rates did not correlate with high versus low FISH+ counts, nor with HER-2 ECD levels. Among 39 HER-2+ (FISH+ and/or IHC3+) efficacy-evaluable pts with qRT-PCR data, there were 13/19 (68.4%) PR for pts with qRT-PCR above median levels, and 7/20 (35.0%) PR for pts with qRT-PCR below median. Conclusions: HER-2+ pts (by central retesting) had better responses to T-DM1 than HER-2- pts, although a small number of PR were observed in HER-2- pts. Assessment of HER-2 expression by qRT-PCR may identify pts more likely to respond to T-DM1 therapy. Updated data, including additional diagnostic markers, will be presented at the meeting. [Table: see text]

1017 Background: T-DM1 is an ADC that combines the biological activity of trastuzumab (T) with targeted delivery of a potent antimicrotubule agent, DM1, to HER2-expressing cancer cells. In a phase I study, T-DM1 was administered IV q3w to pts with HER2+ MBC who had progressed on T + chemotherapy. T-DM1 was well-tolerated at the maximum tolerated dose (MTD) of 3.6 mg/kg, with no reports of cardiac toxicity. The confirmed objective response rate (ORR) for the 9 pts with measurable disease treated at the MTD was 44%. The phase II study described here further assesses tolerability and activity of T-DM1. Methods: This was a multi-institutional, open-label, single-arm phase II study, to enroll 100 pts. All eligible pts had progressed on HER2-directed therapy and had received chemotherapy in the metastatic setting. T-DM1 was administered at 3.6 mg/kg IV q3w. Primary objectives were assessment of ORR and of safety and tolerability. Results: As of the August 29, 2008, data-cut, 112 patients had enrolled, with baseline median age 54.5 (range 33–82); ECOG PS 2 or 3, 80%; 68.7% with > 3 sites of metastatic disease; median 3 (range 1–14) prior chemotherapy agents for metastatic disease, median 76.3 weeks prior T, and 55.4% with previous lapatinib. Due to limited F/U, the median number of T-DM1 cycles received was 5 (range 1–16), and 19 of the 107 efficacy evaluable patients had only one post-baseline tumor assessment. Fifty-six pts had discontinued study treatment. With a median follow-up of 4.4 mos, there were 42 (39.3%) ORs (CR or PR), 29 (27.1%) of which have been confirmed by follow-up (F/U) imaging. Among the subgroup of pts who had either >6 months F/U or had discontinued from the study at any time (n = 76) there were 33 ORs (43.4%), 29 (38.2%) of which were confirmed by F/U imaging. The most common grade 3–4 AE was thrombocytopenia (7.1%). Updated data will be presented at the meeting, including updated ORR, 6-month clinical benefit rate, ORR by independent review, progression-free survival, and duration of response. Conclusions: T-DM1 has single-agent activity in pts with previously treated, HER2+ MBC, and is well tolerated at the recommended phase II dose. [Table: see text]