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Purpose This phase I study assessed the safety of first-in-class radioenhancer nanoparticles, NBTXR3, in elderly or frail patients with locally advanced head and neck squamous cell carcinoma (HNSCC), ineligible for chemoradiation. Methods Patients with stage III or IVA (American Joint Committee on Cancer (AJCC) guidelines, 7th edition, 2010) HNSCC of the oral cavity or oropharynx, aged ≥70 or ≥65 years and ineligible to receive cisplatin, amenable to radiotherapy (RT) with curative intent, received NBTXR3 as a single intratumoural (IT) injection followed by activation by intensity-modulated radiation therapy (IMRT; 70 Gy). The NBTXR3 dose corresponded to a percentage of the baseline tumour volume, measured by magnetic resonance imaging. The primary objectives were to determine the recommended phase II dose (RP2D), dose-limiting toxicities (DLTs) and maximum tolerated dose (MTD). Safety and tolerability were assessed using National Cancer Institute CTCAE version 4.0. Antitumour activity was assessed by Response Evaluation Criteria in Solid Tumours 1.1. Results Nineteen patients were enrolled: 3 at the dose level of 5%, 3 at the dose level of 10%, 5 at the dose level of 15% and 8 at the dose level of 22% of the tumour volume. The MTD was not reached, and no DLTs or serious adverse event (SAEs) related to NBTXR3 were observed. Four adverse events related to NBTXR3 and/or the IT injection were reported (grade I–II). NBTXR3 remained in the injected tumour throughout RT, with no leakage in the surrounding healthy tissues. Specific RT-related toxicity was as expected with IMRT. The RP2D was determined as 22% baseline tumour volume. Preliminary signs of antitumour activity were observed. Conclusion Intratumoural injection of NBTXR3 followed by IMRT is feasible and demonstrated a good safety profile, supporting further evaluation at the RP2D in this patient population. Trial registration ClinicalTrials.gov NCT01946867 .

Novel antibody formats such as bispecifics have increased risk of immunogenicity, impacting safety and efficacy. LY3415244, a novel T-cell immunoglobulin and mucin-domain-containing molecule-3 (TIM3)-PDL1 (programmed death (ligand) 1) bispecific caused neutralizing antibody–drug antibodies (ADA) in 12 of 12 patients and required study termination. Novel approaches are needed to ameliorate and manage this undesirable effect of therapeutic antibodies. See related article by Hellmann et al., p. 2773

Adoptive cell therapy with chimeric antigen receptor T cells has caused a significant revolution in the treatment of hematological malignancies. Unfortunately, for solid tumors, this treatment modality has been proven insufficient to achieve significant antitumor activity. The use of modified T cell receptors towards tumor-associated antigens (NY-ESO, MAGE-A4) has recently shown antitumor activity in synovial sarcoma. Also, treatment with tumor-infiltrating lymphocytes shows clinical activity in metastatic cervical cancer and melanoma resistant to checkpoint inhibitors. Strategies to improve results and broaden the applicability of therapeutic lymphocytes for solid tumors include local delivery, fourth generation chimeric antigen receptor T cells, off-the-shelf T lymphocytes and private neoantigen-directed cells, among others. In this review, we summarize the status of adoptive cell therapy using T cells for solid tumors and the investigational strategies being tested in this field.

BackgroundA majority of patients with advanced NSCLC develop disease progression with first-line immune-checkpoint inhibitors (ICI) ± chemotherapy. In the setting of ICI resistance, effective strategies to provide deep and durable responses are urgently needed. Lifileucel (LN-144) and LN-145 are centrally manufactured (cryopreserved drug-product, 22-day manufacturing process) autologous TIL products that have demonstrated activity in advanced melanoma, cervical cancer, and head and neck carcinoma.1–4 Here, we report the first safety and efficacy data for LN-145 as monotherapy in patients with advanced NSCLC.MethodsIOV-COM-202 (NCT03645928) is a phase 2 multicenter, multicohort, open-label study evaluating autologous TIL cell therapy in patients with solid tumors. We report data from Cohort 3B, investigating LN-145 monotherapy in patients with advanced or metastatic NSCLC. Eligibility required 1–3 prior lines of systemic therapy, including either ICI or oncogene-directed therapy. Treatment included nonmyeloablative lymphodepletion, TIL infusion, and ≤6 interleukin-2 doses. Primary endpoints were safety (incidence of Grade ≥3 treatment-emergent adverse events [TEAEs]) and objective response rate (ORR, investigator-assessed using RECIST v1.1). Exploratory biomarker analyses, including T-cell receptor (TCR) repertoire, were performed.ResultsAs of 24June2021, 28 patients received LN-145 (full-analysis set [FAS]; table 1) and 24 were efficacy-evaluable; all had received prior ICI. TIL were most commonly harvested from lung metastases (57.1%). Safety was consistent with the underlying disease and known TEAE profiles of nonmyeloablative lymphodepletion and interleukin-2. Grade ≥3 TEAEs in ≥30% of patients were thrombocytopenia and anemia. The ORR in the FAS and efficacy-evaluable set was 21.4% (6/28) and 25.0% (6/24; figure 1), respectively. Median duration of response was not reached and 83% (5/6) of responses were ongoing at last follow-up (median study follow-up, 8.2 months). One patient had a complete metabolic response, ongoing at 20.7 months; 2 responses occurred in patients who were PD-L1–negative. All responders received ≥2 prior lines of systemic therapy. Twenty-six patients had TIL available from the final drug-product for TCR repertoire analysis; mean (min-max) number of unique TCR clones was 13,142 (3093–35,734) and Shannon Entropy index was 7.34 (3.7–12). Updated data will be presented.Abstract 458 Figure 1Best percentage change from baseline in target lesion sum of diameters for efficacy-evaluable setAbstract 458 Table 1Baseline patient demographic and clinical characteristics; efficacy parametersConclusionsLN-145 was successfully manufactured and one-time treatment produced an expected safety profile and durable responses in heavily pretreated patients with NSCLC, regardless of PD-L1 expression. The activity of LN-145 monotherapy is encouraging and warrants further investigation of LN-145 as a single-agent and in combination in patients with NSCLC in ongoing studies IOV-LUN-202 (NCT04614103) and IOV-COM-202 Cohorts 3A and 3C (3B closed to enrollment).AcknowledgementsThis study and analysis were funded by Iovance Biotherapeutics, Inc. (San Carlos, CA, USA). Writing support was provided by Amanda Kelly (Iovance); graphics support was provided by Cognition Studio (Seattle, WA, USA).Trial RegistrationNCT03645928ReferencesSarnaik AA, et al. J Clin Oncol 2021; doi: 10.1200/JCO.21.00612.. Thomas SS, et al. J Clin Oncol 2021;39: (suppl; abstract 9537).Jazaeri A, et al. J Clin Oncol 2019;37: (suppl; abstract 2538).Jimeno A, et al. J Immunother Cancer 2020;8: (suppl; abstract A378).Ethics ApprovalThe study was approved by Advarra Institutional Review Board, approval number Pro00035064 and all study participants provided written consent via signature of the IRB-approved Informed Consent form.

Background Eftilagimod alpha (efti) is a soluble LAG-3 protein that binds to a subset of MHC class II molecules to mediate antigen presenting cell (APC) and CD8 T-cell activation. The stimulation of the dendritic cell network and subsequent T cell recruitment may lead to stronger anti-tumor responses in combination with pembrolizumab than observed with pembrolizumab alone. We report results from stage 1 of all parts of the study (NCT03625323). Methods Patients (pts) with unselected PD-L1 expression were recruited into 3 cohorts: part A; 1st line, immunotherapy naive NSCLC; part B; 2nd line, immunotherapy refractory NSCLC and part C; 2nd line immunotherapy naive HNSCC. The study uses a Simon’s 2-stage design, with objective response rate (ORR) by iRECIST as the primary endpoint (EP). Secondary EPs include tolerability, disease control rate (DCR), progression free survival (PFS), overall survival (OS), PK, PD and immunogenicity. Fifty-eight (58) pts were recruited into stage 1. Up to additional 51 pts will be recruited if a pre-specified ORR threshold is met for the respective part. Efti is administered as 30 mg subcutaneous injection every 2 wks for 8 cycles and then every 3 wks for 9 cycles; pembrolizumab is administered at 200 mg intravenous infusion every 3 wks for up to 2 yrs. The study was approved by ethic committees and institutional review boards. Results Between Mar 2019 and Jul 2020 88 pts were enrolled. The median age was 67 yrs (range 53-84) and 70% were male. ECOG PS 0:1 was 42% and 58% respectively. Pts from all PD-L1 tumor expression subgroups were recruited. Pts received a median of 4 (1-25) pembrolizumab and 5.5 (1-22) efti administrations. The most common (≥ 15%) treatment emergent adverse events (TEAEs) were asthenia (28%), cough (27%), decreased appetite (22%), dyspnea (21%), fatigue (18%) and diarrhea (15%). Three (3) pts discontinued due to treatment related AEs. The ORR (acc. to iRECIST) of the 58 patients enrolled into stage 1 is shown in (table1). PK profiles after the first or repeated efti dosing were in line with previous studies, with a mean Cmax at7 ng/ml reached ≤ 24h. Circulating TH1 biomarkers 2 weeks after the last efti administration were increased (3 months vs. baseline) by a mean 61% and 209% for CXCL10 (Student paired t-test, p=0.02, n=31) and IFN-γ(p= 0.02, n=19), respectively. Conclusions Efti plus pembrolizumab is safe and shows encouraging antitumor responses in NSCLC and HNSCC patients Trial Registration NCT03625323 Ethics Approval The study was approved by relevant ethic committees and institutional review boards.

SummaryBackground A phase I study found remarkable activity and manageable toxicity for doxorubicin (bolus) plus lurbinectedin (1-h intravenous [i.v.] infusion) on Day 1 every three weeks (q3wk) as second-line therapy in relapsed small cell lung cancer (SCLC). An expansion cohort further evaluated this combination. Patients and methods Twenty-eight patients with relapsed SCLC after no more than one line of cytotoxic-containing chemotherapy were treated: 18 (64%) with sensitive disease (chemotherapy-free interval [CTFI] ≥90 days) and ten (36%) with resistant disease (CTFI Results Ten patients showed confirmed response (overall response rate [ORR] = 36%); median progression-free survival (PFS) = 3.3 months; median overall survival (OS) = 7.9 months. ORR was 50% in sensitive disease (median PFS = 5.7 months; median OS = 11.5 months) and 10% in resistant disease (median PFS = 1.3 months; median OS = 4.6 months). The main toxicity was transient and reversible myelosuppression. Treatment-related non-hematological events (fatigue, nausea, decreased appetite, vomiting, alopecia) were mostly mild or moderate. Conclusion Doxorubicin 40 mg/m2 and lurbinectedin 2.0 mg/m2 on Day 1 q3wk has shown noteworthy activity in relapsed SCLC and a manageable safety profile. The combination is being evaluated as second-line therapy for SCLC in an ongoing, randomized phase III trial. Clinical trial registrationwww.ClinicalTrials.gov code: NCT01970540. Date of registration: 22 October, 2013.

Inhibidor de BET; Limfoma no Hodgkin; Tumors sòlids Inhibidor de BET; Linfoma no Hodgkin; Tumores sólidos BET inhibitor; Non-Hodgkin's lymphoma; Solid tumors Background Bromodomain and extra-terminal (BET) proteins are epigenetic readers that regulate expression of genes involved in oncogenesis. CC-90010 is a novel, oral, reversible, small-molecule BET inhibitor. Patients and methods CC-90010-ST-001 (NCT03220347; 2015-004371-79) is a phase I dose-escalation and expansion study of CC-90010 in patients with advanced or unresectable solid tumors and relapsed/refractory (R/R) non-Hodgkin's lymphoma (NHL). We report results from the dose escalation phase, which explored 11 dose levels and four dosing schedules, two weekly (2 days on/5 days off; 3 days on/4 days off), one biweekly (3 days on/11 days off), and one monthly (4 days on/24 days off). The primary objectives were to determine the safety, maximum tolerated dose (MTD) and/or recommended phase II dose (RP2D) and schedule. Secondary objectives were to evaluate signals of early antitumor activity, pharmacokinetics, and pharmacodynamics. Results This study enrolled 69 patients, 67 with solid tumors and two with diffuse large B-cell lymphoma (DLBCL). The median age was 57 years (range, 21–80) and the median number of prior regimens was four (range, 1–9). Treatment-related adverse events (TRAEs) were mostly mild and manageable; grade 3/4 TRAEs reported in more than two patients were thrombocytopenia (13%), anemia, and fatigue (4% each). Six patients had dose-limiting toxicities. MTDs were 15 mg (2 days on/5 days off), 30 mg (3 days on/11 days off), and 45 mg (4 days on/24 days off). The RP2D and schedule selected for expansion was 45 mg (4 days on/24 days off). As of 8 October 2019, one patient with grade 2 astrocytoma achieved a complete response, one patient with endometrial carcinoma had a partial response, and six patients had prolonged stable disease ≥11 months. Conclusions CC-90010 is well tolerated, with single-agent activity in patients with heavily pretreated, advanced solid tumors. This work was supported by Celgene Corporation, Summit, NJ, USA. (no grant number).

Lay Summary Currently, the complexity of clinical trial development in oncology is being further complicated by the coronavirus disease 2019 (COVID‐19) pandemic, which is reducing the resources needed to comply with protocol‐specific procedures while putting patients in units, who are already vulnerable, at increased general risk not only for COVID‐19 infection but also with respect to their baseline disease.Individualizing the management of patients while ensuring their safety and adherence to the study protocol, establishing specific staff contingency plans, and maintaining sponsor and contract research organization (CRO) alignment are some of the key issues for maintaining the continuity of cancer patients’ investigational treatment and minimizing their infection risk as well as the risk to staff members of the unit, sponsors, and CROs while maintaining the integrity of data quality and compliance with good clinical practice., This commentary describes the potentially deep, specific, and rapid impact of the coronavirus disease 2019 pandemic on clinical research units in oncology, and it establishes different processes and action plans in order to allow the performance of clinical research activities during this challenging period.

Although the neutrophil-lymphocyte ratio (NLR) is prognostic in many oncological settings, its significance in the immunotherapy era is unknown. Mechanistically, PD-1/PD-L1 inhibitors may alter NLR. We sought to characterise NLR kinetics in patients with advanced solid tumours treated with PD-1/PD-L1 inhibitors.Electronic records of patients treated with PD-1/PD-L1 inhibitors on phase I trials across three sites were reviewed. A high NLR (hNLR) was predefined as5. Univariate logistic regression models were used for toxicity, response analyses and Cox models for overall survival (OS) and progression-free survival analyses. Landmark analyses were performed (cycle two, three). Longitudinal analysis of NLR was performed utilising a mixed effect regression model.The median OS for patients with hNLR was 8.5 months and 19.4 for patients with low NLR, (hazard ratio [HR] = 1.85, 95% confidence interval [CI] 1.15-2.96, p = 0.01). On landmark analysis, hNLR was significantly associated with inferior OS at all time points with a similar magnitude of effect over time (p 0.05). On multivariate analysis, NLR was associated with OS (HR 1.06, 95% CI 1.01-1.11, p = 0.01). NLR did not correlate with increased immune toxicity. Longitudinally, NLR correlated with response: NLR decreased by 0.09 (95% CI: -0.15 to -0.02; p = 0.01) per month in responders compared with non-responders.hNLR at baseline and during treatment is adversely prognostic in patients with advanced malignancies receiving PD-1/PD-L1 blockade. Importantly, NLR reduced over time in responders to immunotherapy. Taken together, these data suggest that baseline and longitudinal NLR may have utility as a unique biomarker to aid clinical decision-making in patients receiving immunotherapy.

BackgroundEftilagimod alpha (efti) is a soluble LAG-3 protein targeting a subset of MHC class II, thus mediating antigen presenting cell (APC) and CD8 T-cell activation. Such stimulation of the dendritic cell network and resulting T cell recruitment by efti may lead to stronger anti-tumor responses than observed with pembrolizumab alone. We hereby report results of the 2nd line metastatic head and neck squamous cell carcinoma (HNSCC) cohort (part C) of the TACTI-002 phase II trial (NCT03625323).MethodsEligible patients (pts) with HNSCC, unselected for PD-L1 expression with disease progression on or after 1st line platinum-based therapy, received 30 mg subcutaneous efti Q2W for 24 weeks and 200 mg pembrolizumab Q3W for up to 2 years or until disease progression. The study used a Simon’s 2-stage design with objective response rate (ORR) as the primary endpoint (EP). Secondary EPs included tolerability, progression free survival (PFS), overall survival (OS), pharmacokinetics, pharmacodynamics, and immunogenicity. Tumor response was assessed Q9W. PD-L1 was assessed centrally (22C3 clone). The study was approved by ethic committees and institutional review boards.ResultsBetween Mar 2019 and Jan 2021, 39 pts were enrolled (cut-off Apr 2021). The median age was 62 yrs (range 37–84) with 90% male pts. ECOG was 0 and 1 in 33% and 67%, respectively. Primary tumor location at diagnosis was oropharynx (36%), oral cavity (31%), hypopharynx (18%) and larynx (15%) with all PD-L1 subgroups (CPS< 1, ≥1 to ≤19; ≥20) being represented. All pts were pre-treated with platinum-based chemotherapy. Thirty-seven (37) pts were evaluated for response with ORR (iRECIST) of 30% (95% CI 16–47%) with 5 (14%) CRs; 6 (16%) PRs; 3 (8%) SDs; 17 (46%) PDs and 6 (16%) pts not evaluable. Median PFS was 2.1 months and 30+% were progression-free at 6 months. One patient (3%) discontinued due to pembro-related adverse event. The most common (>10%) treatment emergent adverse events were hypothyroidism (21%), cough (18%), asthenia (15%), fatigue (13%), anemia (13%), diarrhea (13%) and weight decreased (13%).ConclusionsEfti in combination with pembrolizumab is safe, showing encouraging antitumor activity in platinum pre-treated, 2nd line HNSCC patients. For further investigation of this combination, a 1st line HNSCC trial (NCT04811027) has been initiated.Trial RegistrationNCT03625323Ethics ApprovalThe study was approved by relevant ethic committees and institutional review boards

BackgroundTransforming growth factor beta (TGFβ) is a bifunctional regulator of tumor growth playing a role in tumor immune evasion and resistance to checkpoint blockade. Increased activation of TGFβ pathway correlated with reduced overall survival in patients with PD-1 resistance/refractory tumors. Therefore, the combination of a TGFβ inhibitor with an anti-PD-1 agent may benefit patients who are resistant to checkpoint blockade. SAR439459 is a ”second generation” human anti-TGFβ IgG4 monoclonal antibody. Here we report the preliminary PD results and patient selection strategy (mesenchymal CRC) of SAR439459 ± anti-PD-1 cemiplimab in patients with advanced tumors from an on-going phase 1 study (NCT03192345).MethodsPeripheral blood, serum and tumor biopsies from patients were collected for the assessment of both predictive and PD biomarkers. A consensus molecular subtyping 4 (CMS4) gene classifier was developed and used to identify mesenchymal CRC tumors based on an in-silico experiment followed by a validation using ~200 procured CRC tumor biopsy samples with customized NanoString assay. TGFβ level in plasma and tumor was measured by ELISA to assess target engagement of SAR439459. Well-known immune modulation events as the PD readout were measured: 1) immunophenotyping of circulating immune cells ; 2) cytokine/chemokine production by MSD assay; 3) PD-L1, CD8+ T cells and FoxP3+ Tregs in tumor micro-environment (TME) by immunohistochemistry; 4) TGFβ pathway activation gene signature in TME by RNAseq.ResultsSAR439459 ± cemiplimab, induced inhibition of plasma TGFβ level ≥ 90% at doses ≥ 0.25mg/kg Q2W, together with a clear trend of decrease in intra-tumoral TGFβ. RNAseq data from paired biopsies revealed concomitant down-regulation of TGFβ pathway. In periphery, SAR439459 ± cemiplimab increased proliferating T and NK cells. Concomitantly, enhanced production of pro-inflammatory cytokines/chemokines confirmed peripheral immune activation. In TME, a trend of increased CD8+ T cell infiltration and conversion from ”immune-excluded” to ”immune-inflamed” phenotype was observed following the combination treatment in several cases. No significant modulation of PD-L1 or FoxP3 was observed from the available paired biopsies. Out of 137 pre-screened CRC patients, 58 (42%) were identified as carrying the CMS4 phenotype based on the gene classifier.ConclusionsClinical modulation of TGFβ level and the related pathway demonstrated SAR439459’s target engagement. Further analysis confirmed the peripheral immune activation in patients treated with SAR439459 ± cemiplimab. Coupled with CD8+ T cell modulation in TME, these findings suggest the identification of early PD biomarkers impacted by SAR439459 which is consistent with the mechanism of action and biological activity of TGFβ blockade therapy.Trial RegistrationNCT03192345Ethics ApprovalThe study protocols were approved by the institutional review board or independent ethics committee of each participating institution. All patients provided written informed consent priorto enrollment.ConsentWritten informed consent was obtained from the patient for publication of this abstract and any accompanying images. A copy of the written consent is available for review by the Editor of this journal.

PURPOSE/OBJECTIVE(S) Concurrent radiotherapy (RT) with high-dose cisplatin, or cetuximab in case of intolerance to cisplatin, are the non-surgical standard treatment for locally advanced head and neck squamous cell carcinoma (LA HNSCC). However, elderly patients, patients with poor performance status, comorbidities, and/or intolerance may not benefit from these treatments and represent a high unmet medical need. New approaches are thus needed to improve the patient clinical outcomes without adding toxicity. NBTXR3, composed of functionalized hafnium oxide nanoparticles, is injected once intratumorally and activated by RT. NBTXR3 increases the RT energy deposit inside tumor cells and subsequently increases tumor cell death compared to RT alone, without adding toxicity to healthy tissues. We present here current results of the dose expansion part of the phase I study evaluating NBTXR3 plus intensity modulated radiation therapy (IMRT) in this population (ClinicalTrials.gov: NCT01946867). MATERIALS/METHODS Patients with stage III-VA or T3/T4 (AJCC/UICC TNM staging system 8th ed.) HNSCC of the oropharynx or oral cavity, ineligible to cisplatin or cetuximab and amenable for RT, received a single intratumoral injection of NBTXR3 and IMRT (70 Gy in 35 fractions /7 weeks). A classical 3 + 3 dose escalation design has tested four doses of NBTXR3, equivalent to 5, 10, 15, and 22% of baseline theoretical tumor volume. The RP2D established as 22% of baseline tumor volume is further tested in the dose expansion part of the study. The primary endpoints of the dose expansion part are objective response rate (ORR) and complete response rate (CRR) of the primary tumor, by imaging according to RECIST v1.1. Safety is also evaluated. RESULTS As of August 13, 2020, 43 patients have been treated in the dose expansion part of the study. The median age was 70.7 years old (range: 50.7- 89.9), 70% of patients had cardiac disorder risk, 44% had gastrointestinal disorder risk and 44% metabolic and nutrition disorder risk. The median tumor volume was 42.8 mL (range: 1.3 - 222.3). In the evaluable population for efficacy (N = 31), the ORR of the primary lesion was 83.9% and the CRR 67.7% at a median time of 7.8 months after NBTXR3 injection. Three patients (7%) experienced at least one serious adverse event (AE) related to the injection procedure and/or NBTXR3 which represented less than 1% of all reported AEs. RT-related toxicity was as expected with IMRT. Three deaths due to AEs related to RT and other causes were reported. The recruitment is ongoing and updated efficacy and safety results will be presented. CONCLUSION NBTXR3 intratumoral administration followed by IMRT may represent an option in elderly in elderly patients or patients with multiple comorbidities with LA-HNSCC who have limited therapeutic options. NBTXR3 activated by RT showed promising anti-tumor efficacy, supporting further evaluation in a phase III randomized trial.

Cutaneous squamous cell carcinoma (cSCC) is the second most frequent type of malignancy in Caucasians worldwide. Several factors have been correlated with aggressiveness and likelihood of recurrence and distant metastases, which are challenging to control. Metastatic disease has a dismal prognosis, and standard chemotherapy has failed to significantly improve outcomes. Recently, it has been recognized that cSCCs are highly mutated tumors with a denoting potential likelihood of response to immune checkpoint blockade. Cemiplimab is an anti-programmed cell death protein 1 (PD-1) antibody recently approved for the treatment of unresectable locally advanced or metastatic cSCC by the U.S. Food and Drug Administration (FDA) and the European Commission with a compelling response rate and an acceptable safety profile.

Background TIL (especially CD8+ T cells) in the tumor microenvironment is associated with survival outcomes in many solid tumors, including melanoma (Mel), head and neck squamous cell carcinoma (HNSCC), and non-small cell lung cancer (NSCLC). Lifileucel (LN-144), has shown efficacy with durable responses in advanced melanoma (Mel) (Sarnaik et al., ASCO 2020), metastatic cervical cancer (Jazaeri et al., ASCO 2019), and LN-145 + pembrolizumab in HNSCC (Jimeno et al., SITC 2020). TIL therapy has shown evidence of efficacy in metastatic NSCLC in a Phase 1 study (Creelan et al., ASCO 2020). Methods IOV-COM-202 (NCT03645928) is a Phase 2 global, open-label multi-cohort, non-randomized study designed to evaluate the safety and efficacy of TIL therapy as a single agent or in combination with immune checkpoint inhibitors. All patients receive either, lifileucel, LN-145 or LN-145-S1 (PD-1 select TIL), which is manufactured at centralized GMP facilities generating a cryopreserved infusion product which is shipped to the treatment centers. Cohort 1, 2 and 3 enroll Mel, HNSCC and NSCLC patients, respectively (Table 1). Patients undergo a nonmyeloablative lymphodepletion (NMA-LD) regimen prior to TIL infusion, followed by up to 6 doses of intravenous IL-2. Patients in Cohorts 1A, 2A, and 3A start pembrolizumab following tumor harvest for TIL generation, but prior to NMA-LD. Pembrolizumab is dosed per label. Patients in Cohorts 1B, IC and 3B receive LN-145-S1, lifileucel, and LN-145, respectively. Cohort 3C patients receive a dose of ipilimumab and nivolumab prior to tumor harvest, with nivolumab continuing Q4W for up to 2 years, or until progression or unacceptable toxicity. Key eligibility includes: ≥ 18 years of age; RECIST measurable disease; ≥ 1 lesion(s) available for TIL generation; ECOG PS 0-1. The primary endpoint: ORR per RECIST v1.1. Secondary endpoints: safety, CR rate, DOR, DCR, PFS, and OS. Table 1.IOV-COM-202 Study DesignCohortTIL ManufacturingCohort 1A: Melanoma PD-1/ PD-L1 Naïve LN-144 + Pembrolizumab N=12LN-144: 22-day manufacturingCohort 1B: Melanoma ≥1 prior systemic therapies LN-145-S1 N up to 27LN-145-S1: PD-1 selected TILCohort 1C: Melanoma ≥1 prior systemic therapies LN-144 Gen 3 N up to 27LN-144 Gen 3: 16-day manufacturingCohort 2A: Head and Neck PD-1/ PD-L1 Naïve LN-145 + Pembrolizumab N=19LN-145: 22-day manufacturingCohort 3A: NSCLC PD-1/ PD-L1 Naïve LN-145 + Pembrolizumab N=12LN-145: 22-day manufacturingCohort 3B: NSCLC ≥1 prior systemic therapies LN-145 N=12LN-145: 22-day manufacturingCohort 3C: NSCLC 1 prior systemic therapy TIL + Ipilimumab / Nivolumab N up to 26 Citation Format: Scott Gettinger, Harriet Kluger, Adam Schoenfeld, Allison Betof-Warner, Kai He, Ammar Sukari, Bernard Doger de Speville Uribe, Sylvia Lee, Simon Haefliger, Zelanna Goldberg, Alex Cacovean, Rana Fiaz, Guang Chen, Madan Jagasia, Friedrich Graf Finckenstein, Maria Fardis, Antonio Jimeno. A Phase 2, multicenter study of autologous tumor infiltrating lymphocytes (TIL, LN 144/LN-145/LN-145-S1) in patients with solid tumors [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 CT235.

6028 Background: Eftilagimod alpha (efti) is a soluble LAG-3 protein that binds to a subset of MHC class II molecules to mediate antigen presenting cell (APC) activation and CD8 T-cell activation. The stimulation of the dendritic cell network and subsequent T cell recruitment with efti may lead to stronger anti-tumor responses in combination than observed with pembrolizumab alone. We hereby report results of the 2nd line metastatic squamous head and neck carcinoma (HNSCC) cohort (part C) of phase II trial (NCT03625323). Methods: Patients (pts) with HNSCC progressed on or after 1st line platinum-based therapy and unselected for PD-L1 expression were recruited into part C. The study used a Simon's 2-stage design (18 pts planned for stage 1 and 19 for stage 2), with objective response rate (ORR) by iRECIST as the primary endpoint (EP). Secondary EPs include tolerability, disease control rate (DCR), progression free survival (PFS), overall survival (OS), pharmacokinetics, pharmacodynamics and immunogenicity. Efti was administered as 30 mg subcutaneous injection every 2 wks for 8 cycles and then every 3 wks for 9 cycles with pembrolizumab (200 mg intravenous infusion every 3 wks for up to 2 yrs). Imaging was performed every 8 weeks. PD-L1 was assessed centrally (22C3 clone). The study was approved by ethics committees and institutional review boards. Results: In total 38 pts were enrolled. The median age was 62 yrs (range 37-84) and 89 % were male. The ECOG PS was 0 and 1 in 34% and 66%, respectively. Primary location at diagnosis was the oral cavity (29%), oropharynx (37%), hypopharynx (18%) and the larynx (16%). All PD-L1 subgroups (CPS < 1 %, ≥ 1 to ≤19; ≥20) were included. All pts were pre-treated with platinum-based chemotherapy. Pts received a median of 3.0 (range 1 – 21) pembrolizumab and 5.0 (range 1-31) efti administrations. Thirty-five (35) pts were evaluated for response (cut-off Jan 2021) with 4 (11 %) pts showing CR, 7 (20 %) pts PR, 3 (9 %) pts SD, 16 (46 %) pts PD with 5 (14 %) pts being not evaluable as per iRECIST. ORR was reported with 31.4 % (95 % CI 16.9 % - 49.3 %) and DCR 40 %Median PFS was 2.1 months and 35 % were progression free at 6 months. Median OS (46 % events) was 12.6 months. There were no adverse reactions leading to treatment discontinuation. The most common ( > 10 %) treatment emergent adverse events were cough (18 %), asthenia (16 %), dyspnea (11 %), fatigue (13 %), diarrhea (11 %), hypothyroidism (11%), upper respiratory tract infection (11%) and back pain (11%). Conclusions: Efti in combination with pembrolizumab is safe and shows encouraging antitumor activity in platinum pre-treated 2nd line HNSCC patients. Clinical trial information: NCT03625323.

9537 Background: Tumor infiltrating lymphocyte (TIL) cell therapy has demonstrated safety and efficacy in advanced melanoma, both in the pre-immune checkpoint inhibitor (ICI) setting (Goff, JCO 2016) and in patients who have failed anti-PD-1/PD-L1 therapy (Sarnaik, 2020). Combination of TIL and pembrolizumab (pembro) in ICI-naïve patients has demonstrated encouraging efficacy data with acceptable safety in head and neck squamous cell carcinoma (Jimeno, 2020). To improve treatment options in early lines, we explore a combination of LN-144 and pembro in patients with ICI-naïve advanced melanoma. Methods: IOV-COM-202 is a Phase 2 multicenter, multi-cohort, open-label study evaluating TIL cell therapy in multiple settings and indications. We report on Cohort 1A enrolling ICI-naïve advanced melanoma (unresectable or metastatic) patients for treatment with a combination of LN-144 and pembro. Key eligibility criteria include ≤ 3 lines of prior therapy, ECOG < 2, one resectable lesion for lifileucel manufacturing, and ≥ 1 measurable lesion for response assessment. Primary endpoints are objective response rate (ORR) per RECIST 1.1 and safety as measured by incidence of Grade ≥3 treatment-emergent adverse events (TEAE). LN-144 is generated at centralized GMP facilities in a 22-day process. A nonmyeloablative lymphodepletion (NMA-LD) using cyclophosphamide and fludarabine is administered preceding a single LN-144 infusion, followed by < 6 doses of IL-2 (600,000 IU/kg). Pembro is administered after tumor harvest but prior to NMA-LD and continues after lifileucel per label. Results: Seven patients have received lifileucel in combination with pembro as of data extraction date (Feb 14, 2021). Five of the 7 treated patients were treatment-naïve, 1 patient had prior BRAFi + MEKi and 1 had received prior chemotherapy; 71% had liver/brain lesions, 43% had LDH > ULN. Mean SOD for the target lesions was 111 mm, with 86% of patients with > 3 target lesions, representing advanced disease at baseline for this patient group. The TEAE profile was consistent with the underlying disease and known AE profiles of pembro, NMA-LD and IL-2. Six patients had a confirmed objective response with an ORR of 86% (1 CR, 5 PR) and 1 best response of SD. Three of the responding patients have remained off pembro due to pembro related AEs for 3, 4 and 13 months (mos), yet maintaining response. All responding patients remain in response with the longest duration of response being 16.8 mos. Conclusions: Lifileucel can be safely combined with pembro in patients with ICI-naïve advanced melanoma. The ORR of 86% is encouraging when compared to pembro alone in a similar patient population, especially considering the disease burden at baseline and persistence of responses in patients off therapy. Enrollment is ongoing and updated data to be presented. Clinical trial information: NCT03645928.

6051 Background: The non-surgical standard of care (SOC) for the treatment of locally advanced head and neck squamous cell carcinoma (LA HNSCC) patients is concurrent chemoradiation with high dose cisplatin or cetuximab in case of contra-indication to cisplatin. However elderly patients, and those with poor performance status, comorbidities, and/or intolerance, may not benefit from these SOC treatments and represent a high unmet need. New approaches are thus needed to improve clinical outcomes without adding toxicity. NBTXR3, a novel radioenhancer, composed of functionalized hafnium oxide nanoparticles, is injected once intratumorally and activated by radiotherapy (RT).NBTXR3 increases the RT energy deposit inside tumor cells and subsequently increases tumor cell death compared to RT alone, while sparing healthy tissues. We present here the results of the dose expansion part of the phase I study evaluating NBTXR3 plus intensity modulated radiation therapy (IMRT) in this population. Methods: Patients with stage III-IVA or T3/T4 (AJCC/UICC TNM staging system 8th ed.) HNSCC of the oropharynx or oral cavity, ineligible to cisplatin or cetuximab and amenable for RT, received a single intratumoral injection of NBTXR3 and IMRT (70 Gy in 35 fractions /7 weeks). A classical 3 + 3 dose escalation design has tested four doses of NBTXR3, equivalent to 5, 10, 15, and 22% of baseline theoretical tumor volume. The RP2D established as 22% of baseline tumor volume is further tested in the dose expansion part. The primary endpoints of the dose expansion part are objective response rate (ORR) and complete response rate (CRR) of the primary tumor, by imaging according to RECIST 1.1. Safety is also evaluated. Results: As of August 13, 2020, 43 patients have been treated in the phase I dose expansion part. The median age was 70.7 years old (range: 50.7- 89.9), 70% of patients had cardiac disorder risk, 44% had gastrointestinal disorder risk and 44% metabolic and nutrition disorder risk. The median tumor volume was 42.8 mL (range: 1.3 - 222.3). At a median time of 7.8 months after NBTXR3 injection, the ORR of the primary lesion was 83.9% and the CRR 67.7% in the evaluable population for efficacy (N = 31). Three patients (7%) experienced at least one serious adverse event (AE) related to the injection procedure and/or NBTXR3 which represented less than 1% of all reported AEs. RT-related toxicity was as expected with IMRT. Three deaths due to AEs related to RT and other causes were reported. The recruitment is ongoing and updated efficacy and safety results will be presented. Conclusions: NBTXR3 intratumoral administration followed by IMRT may represent an option in elderly patients or patients with multiple comorbidities with LA-HNSCC who have limited therapeutic options. NBTXR3 activated by RT showed promising anti-tumor efficacy, supporting further evaluation in a phase III randomized trial. Clinical trial information: NCT01946867.

9046 Background: Eftilagimod alpha (efti) is a soluble LAG-3 protein that binds to a subset of MHC class II molecules to mediate antigen presenting cell (APC) activation and CD8 T-cell activation. The stimulation of the dendritic cell network and subsequent T cell recruitment with efti may lead to stronger anti-tumor responses in combination than observed with pembrolizumab alone. We hereby report results of the 1st line non-small cell lung carcinoma (NSCLC) part of the phase II trial (NCT03625323). Methods: Patients (pts) with untreated, immunotherapy naïve, advanced NSCLC unselected for PD-L1 expression were recruited into part A. The study used a Simon's 2-stage design (17 pts planned for stage 1 and 19 pts for stage 2), with objective response rate (ORR) by iRECIST as the primary endpoint (EP). Secondary EPs include tolerability, disease control rate (DCR), progression free survival (PFS), overall survival (OS), PK, PD and immunogenicity. Efti is administered as 30 mg subcutaneous injection every 2 wks for 8 cycles and then every 3 wks for 9 cycles with pembrolizumab (200 mg intravenous infusion every 3 wks for up to 2 yrs). Imaging was performed every 8 weeks locally and with blinded independent central review (BICR) retrospectively. The study was approved by ethic committees and institutional review boards. Results: In total 36 pts were enrolled. At data cut-off (Jan 2021; median FU of 14 months), the median age was 69 yrs (range 53-84) and 69 % were male. The ECOG PS 0 and 1 was 42% and 58% respectively. Patients had squamous (42%) and non-squamous (58%) NSCLC and 95% presented with metastatic disease. All PD-L1 subgroups (TPS < 1 %, ≥ 1 % to ≤49 %; ≥50 %) were represented with 36% pts having ≥50% TPS. Pts received a median of 7.0 (range 1 – 31) pembrolizumab and 11.5 (range 1-22) efti administrations. Responses as per BICR and local read are shown in the table. ORR (local, iRECIST) by different PD-L1 subgroups was 27% for pts with TPS 20 %) treatment emergent adverse events (AEs) were asthenia (47 %), cough (36 %), decreased appetite (36 %), dyspnea (32 %), pruritus (31 %), fatigue (28 %), diarrhea (25 %), anemia (25 %), constipation (25 %) and back pain (22%). Two patients discontinued treatment due to adverse reactions (Grade 4 immune-mediated hepatitis, Grade 3 AST+ALT increase). Conclusions: Efti in combination with pembrolizumab is safe and shows encouraging antitumor activity in 1st line advanced NSCLC patients across all PD-L1 (TPS) levels. Clinical trial information: NCT03625323. [Table: see text]

The use of monoclonal antibodies directed against programmed cell death protein 1 (PD-1) and its ligand, programmed cell death 1 ligand 1 (PD-L1), widely extends to a large number of tumors such as melanoma, non-small cell lung, renal or lymphomas, among others. Some of them are already approved as first- or second-line treatment, as pembrolizumab, nivolumab or cemiplimab. Dostarlimab is an investigational humanized anti-PD-1 that is being developed both in monotherapy and as combination therapy, for gynecological tumors but also for lung cancer or melanoma. The preliminary results, particularly in endometrial cancer, show a high affinity against PD-1 with encouraging clinical activity. Here we summarize the development of this compound as well as the current preclinical and clinical data and potential future development.

Background: PDXs have become a core component of translational cancer research. Developing these models can become challenging since little is known about which factors influence engraftment rates. We sought to determine which clinical, pathological or molecular factors may predict a higher chance of success for PDX development. Methods: Between March 2017 and August 2019, biopsies obtained from patients with primary or metastatic cancer were implanted into athymic nude mice. Statistical analyses were performed to identify factors that could correlate with final engraftment defined as tumor volume of 150 mm3 in at least three consecutive measurements. We focus on clinical (patient factors) pathological (tumor sample) and molecular characteristics (tumor sample). Information regarding sampling process was also analyzed. Results: 440 tumor samples were collected and implanted. 15 failed due lack of tumor cells. Of 425 tumor-positive samples, 143 PDXs achieved successful growth at time of analysis. The following clinical characteristics were correlated with engraftment success: systemic steroid administration within 2 weeks of sampling (45.5% (30/66) within the steroids-receiving group achieved growth vs 31% (113/359) no-steroids) (p: 0.027). High neutrophils/lymphocytes (NLR) ratio (>5) (42.3% (47/111) of tumors with NLR>5 achieved growth vs 30% (96/313) in the NLR30%): 34% (16/47) (p:0.029). The presence of mucinous cells (signet ring cells) was also correlated with higher chance of tumor engraftment (50% (19) vs. 32% (124/387) (p: 0.022). Negativity for estrogen receptors could also be a positive predictive marker (14% (8/57) of ER+ achieved growth vs 46.7% (7/15) ER negative (p: 0.011). Lastly, sampling source (either primary of metastatic tumors) was not correlated with successful growth. Conclusions: tumors with higher Ki67, mucinous features and ER expression negative have higher chance of PDX development. Some clinical characteristics can also interfere with PDXs development such as use of steroids or NLR. Citation Format: Tatiana Hernandez, Natalia Baños, Victoria Bonilla, Laura del Puerto, Bernard Doger, Jesus Garcia-Foncillas, Michael Wick, Victor Moreno. Predictive factors for successful growth of patient derived xenograft (PDX) [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5045.

Background: Patient-derived xenografts (PDX) as xenotransplantation of human tumors into athymic nude mice have become the hallmark of preclinical modelling in cancer research. They are particularly useful in the characterization of targeted therapies in drug development. We sough to build a collection of PDX connected to our early phase trials facility for preclinical testing of new drugs. Methods: Between March 2017 and October 2019, a total of 483 samples from patients with cancer were obtained for implant. A full review of the characteristics including histological particularities, molecular findings and treatment experience was reviewed for a full description of the collection. Results: 483 tumor samples were implanted. A total of 157 achieved tumor growth (defined as a target volume of 150 mm3 in at least three consecutive measurements). Here, we present the description of 121 successfully engrafted models passed at least 2 times from initial implant. Most common type of cancer is colorectal adenocarcinoma (CRC=63; 52%) (MSI-H=8, 13%). 20 are molecularly characterized: KRAS: 9 (45%); NRAS=1 (5%) and BRAF=4 (20%). Prior therapy: chemo=16, VEGFi=9, EGFRi=1, ICi=1. Fifteen ovarian carcinomas (12,39%). Three BRCA2m (2) and EPCAMm (1). Eight breast carcinomas (6,6%): 6 Invasive Ductal Carcinomas (IDC) (three are triple negative with BRCA2m; 3 resistant to aromatase inhibitors, and 1 to a CDK inhibitor), 1 papillary carcinoma and 1 medullary carcinoma harboring a TP53 mutation. Eleven non-small cell lung cancers grew successfully, all EGFRwt (KRASm=2). One squamous cell carcinoma with a BRD4/NUTM1 fusion treated with cisplatin/vinorelbine and atezolizumab prior to implant. Eight glioblastomas (prior temozolomide=3 (37%), MGMTmt=5 (62%) and IDHm=1 (12%). One uveal melanoma with a MET fusion. The collection also includes endometrial MSI-H cancers (2), bladder (2), head and neck (1), kidney (4), pancreas (2), biliary tract (1) and cervix carcinomas (1) and one osteosarcoma. Conclusions: The importance of PDX development programs relies on the reproducibility of tumors with specific oncogenic drivers potentially targetable. A full comprehensive characterization of PDX shareable collections are paramount for tracking of molecular, diagnostic, prognostic and predictive markers of drug response. Citation Format: Natalia Baños, Tatiana Hernandez-Guerrero, Victoria Bonilla, Bernard Doger, Laura Del Puerto, Emily Robb, Cecilio Cadena, Jesus Garcia-Foncillas, Victor Moreno, Michael Wick. Establishment of a comprehensive patient derived xenograft (PDX) collection for use in precision medicine; A project from START Madrid- FJD [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5061.

6573 Background: The standard of care non-surgical approach for locally advanced head and neck squamous cell carcinoma (LA HNSCC) patients (pts) is concurrent chemoradiation with high dose cisplatin or cetuximab in case of contra-indication. Older age is a contra-indication to cisplatin, and cetuximab might not improve survival in older pts. It is therefore urgently needed to develop new treatment options for elderly pts with LA HNSCC. NBTXR3 are hafnium oxide nanoparticles that can enhance the efficacy of radiotherapy (RT) by increasing locally the deposited dose. In this phase I clinical trial we aimed to evaluate the feasibility and safety of NBTXR3 administered as intratumoral (IT) injection prior to RT in LA HNSCC elderly pts. Methods: Pts with stage III-IV LA HNSCC of the oropharynx or oral cavity ineligible for platinum-based chemoradiation received a single IT injection of NBTXR3 into a selected primary tumor and intensity modulated RT (IMRT; 70 Gy/35 fractions/7 weeks) [NCT01946867]. A 3+3 dose escalation design, tested NBTXR3 dose levels equivalent to 5, 10, 15, and 22% of baseline tumor volume, followed by a dose expansion at the Recommended Phase II Dose (RP2D). Primary endpoints included RP2D determination, and early dose limiting toxicities (DLT). NBTXR3 intratumoral bioavailability and anti-tumor activity (RECIST 1.1) were also evaluated. Results: Enrollment was completed at all dose escalation levels: 5% (3 pts), 10% (3 pts), 15% (5 pts), and 22% (8 pts). No early DLT or SAE related to NBTXR3 or injection were observed. The median follow-up from NBTXR3 administration is 7.6 months. One AE (Grade 1) related to NBTXR3 and four AEs (Grade 1-2) related to the injection were observed. RT-related toxicity was as expected with IMRT. CT-scan assessment showed a good dispersion of NBTXR3 throughout the injected tumor and not in surrounding healthy tissues. The RP2D was determined to be 22%. Preliminary efficacy was evaluated in pts who received the intended dose of NBTXR3 and RT. A complete response of the injected lesion was observed in 9/13 (69%) evaluable pts at doses ≥10% (2 unconfirmed) and an overall complete response in 5/13 (38%) evaluable pts at doses ≥10%. Preliminary safety and efficacy data of the dose expansion cohort at the RP2D will also be presented. Conclusions: NBTXR3 activated by RT was well tolerated at all tested doses and demonstrated promising preliminary anti-tumor activity. Recruitment is ongoing in the dose expansion cohort. These results demonstrate that further testing of NBTXR3 in this population is warranted. Clinical trial information: NCT01946867 .

3100 Background: Eftilagimod alpha (efti) is a soluble LAG-3 protein that binds to a subset of MHC class II molecules to mediate antigen presenting cell (APC) activation and then CD8 T-cell activation. The stimulation of the dendritic cell network and subsequent T cell recruitment with efti may lead to stronger anti-tumor responses than observed with pembrolizumab alone. We hereby report initial results of a phase II trial (NCT03625323). Methods: A predefined number of patients (pts) are recruited into this 3-cohort trial irrespective of PD-L1 expression; part A: 1st line, PD-X naïve NSCLC; part B: 2nd line, PD-X refractory NSCLC and part C: 2nd line PD-X naive HNSCC. The study has a Simon's 2-stage design, with objective response rate (ORR) as primary endpoint. Secondary endpoints include disease control rate, progression free and overall survival, PK, PD and immunogenicity. Additional pts (N2) will be recruited for each part if pre-specified thresholds for ORR are met. Up to 109 pts will be enrolled. Efti is administered as 30 mg subcutaneous injection every 2 wks for 8 cycles and then every 3 wks for 9 cycles with pembrolizumab (200 mg intravenous infusion every 3 wks for up to 2 yrs). The study was approved by ethic committees and institutional review boards. Results: Between 04 Mar 19 and 31 Jan 2020, 48 pts were enrolled and evaluated for safety and exposure. The median age was 66 yrs (range 48-84) and 73 % were male. The ECOG was 0 in 50 % and 1 in 50 % of pts, respectively. Pts received a median of 5 (7) and in total 311 (413) pembrolizumab (efti) administrations, respectively. Three pts (6.3 %) discontinued study treatment due to AEs. The most common ( > 10%) adverse events (AEs) being cough (31 %), asthenia (23 %), decreased appetite (19 %), fatigue (19 %), dyspnea (17 %), diarrhea (15 %) and constipation 13 %). From part A all pts (n = 17) were evaluated. Eight pts (47 %) had a partial response (iPR) and six (35 %) had stable disease according to iRECIST representing an ORR (DCR) of 47 % (82 %). irPRs were observed in all different PD-L1 groups ( < 1%; ≥ 1 % ≤49 %; ≥ 50 %). Ten (10; 59 %) pts are still on therapy (8+ months). In part C stage 1 15/18 pts are evaluable and six (40 %) had an iPR to date. Conclusions: Efti in combination with pembrolizumab is safe and shows encouraging antitumor activity in all comer PD-L1 1st line NSCLC and 2nd line HNSCC. Stage 2 has opened for both parts. Clinical trial information: NCT03625323 .

e15071 Background: To date there are no clear predictors of response to novel immune checkpoint inhibitor (ICI) combinations. Recent reports suggest that HLA-I (Human Leukocyte Antigen Class I) supertype B44 may predict survival to PD1(L)1 inhibition in patients with melanoma and non-small cell lung cancer (NSCLC) ( Chowell et al, Science 2018). We sought to study if this effect is exclusive for PD(L)1 inhibition alone and the impact of HLA-B44 on ICI combinations with new immunotherapeutic agents. Methods: Between 2017 and 2019, 77 patients treated across 11 different early phase clinical trials (NSCLC: 64: (83,1%); melanoma: 4: (5,2%), bladder 8 (10,4%); and one nasopharynx carcinoma), ICI-naive were prospectively evaluated for HLA-I subclass. All patients were ECOG 0 or 1 (50 and 27 respectively). Most patients had ≤ 2 metastatic sites (55: 71,4%); 24 (31,2%) patients were treated with PD(L)1 inhibitors as monotherapy, and 53 (68.8%) with PD(L)1-containing combinations including ICI and agonists such as ICOS, OX40 or GITR monoclonal antibodies. HLA-I was classified for supertypes and the variables of progression-free survival (PFS) and overall survival (OS) were compared for patients with HLA-B44+ and B44-, in both groups (monotherapy and combinations). Results: 44 patients were HLA-B44+ and 33 were negative. For patients treated with anti-PD(L)1 agents as monotherapy, those that were HLA-B44+ had a longer PFS: [medianPFS: 22,38 months (m) (95% CI: 13,39 – 31,37); vs 3,8m (95% IC: 2,05 – 5,65); p: 0,002] and OS: [median: 33,2 m (95% CI: 23,7 – 42,6) vs 14,46 m (95% IC: 7,86 – 21,1); p: 0,13]. In contrast, these marked differences were not evident in patients receiving PD1 combination therapies [HLA-B44+ mPFS: 7,17m (95% CI: 4,41 - 9,93) vs 9,46 m (IC95% 6,8 m – 12,07); p:0,290], and OS: 11,53m (95% IC: 8,33 – 14,7) vs 18,9 m (IC 95% 13,3 – 24,5) p: 0,24. Lastly, response rate was also better for patients with HLA-B44 positive treated with PD1 monotherapy (66,7% vs 16,7% in HLA-B44 negative patients) p: 0,048, whilst when administering ICI combinations, HLA-B44 negative patients seemed to have a better response rate (44% vs 27% in HLA-B44 positive patients; p = 0,148). Conclusions: These results confirm in a prospective cohort the predictive impact of HLA-B44 supertype for patients treated with anti-PD(L)1 agent and suggest a potential benefit of combining checkpoint inhibitors in patients with other HLA supertypes (non-HLA-B44+).

Background: The use of novel agents such as checkpoint inhibitors and the combination with targeted therapies has been increasing exponentially in the last years. Because of this the toxicity profile has been changed and uncommon syndromes are more frequent nowadays. PRES is a rare syndrome that causes neurological acute symptoms such as bradypsychia, seizure and even irreversible blindness if treatment is not initiated soon enough. It has been related to multiple diseases and conditions including with chemotherapy drug combinations and with the use of new oncological drugs. The incidence will probably increase in the net years, so we should describe these cases and develop clinical guidelines for the diagnosis and management of PRES. Case Presentation: Here we present a 64-year-old woman with a stage IV adenocarcinoma of the lung that developed PRES during treatment with a combination of ramucirumab, a monoclonal antibody against vascular endothelial growth factor 2 (VEGFR2), and durvalumab, an antagonist of programmed death-ligand 1 (PD-L1). She developed the syndrome with complete remission of symptoms after two weeks, requiring an adjustment of antihypertensive medications. Conclusions: The clinical importance of this case lies in the fact that despite its low incidence, we should be aware of these potential toxicities with the increasing use of novel agents in different combinatorial strategies, mainly in patients with other comorbidities. An early diagnosis is crucial since the prognosis depends upon it, decreasing the risk of permanent neurological damage and even death.

This phase 1b, open-label trial assessed the combination of afatinib, an ErbB family blocker, with cetuximab, an epidermal growth factor receptor (EGFR) monoclonal antibody, in heavily pretreated patients with unselected/EGFR wild-type, advanced solid tumours. In Part A, the maximum tolerated dose (MTD) of afatinib + cetuximab was evaluated using a 3 + 3 dose-escalation design; the starting dose was afatinib 30 mg/day plus cetuximab 250 mg/m2/week (after cetuximab 400 mg/m2 loading dose), escalating to afatinib 40 mg/day. Part B further evaluated safety and tolerability at the MTD and preliminary anti-tumour activity in three patient cohorts with squamous non–small cell lung cancer (NSCLC), head and neck squamous cell carcinoma (HNSCC) and other solid tumours. Nine patients were treated in Part A; the MTD and recommended dose was determined as afatinib 40 mg/day plus cetuximab 250 mg/m2/week. In Part B, 49 patients were treated at the recommended dose (12 with squamous NSCLC, 15 with HNSCC and 22 with other tumours). The most common treatment-related adverse events (AEs) across all 58 patients were diarrhoea (63.8%) and acneiform dermatitis (43.1%). Overall, the best confirmed response was stable disease (SD; 53.4%); mean duration of disease control was 4.5 months; median progression-free survival was 2.6 months. In Part B, 55.1% of patients had SD (squamous NSCLC, 75.0%; HNSCC, 66.7%; other tumours; 36.4%). In conclusion, the recommended phase 2 dose was determined as afatinib 40 mg/day plus cetuximab 250 mg/m2/week. AEs were predictable and manageable, and anti-tumour activity was observed in some patients, particularly in those with squamous NSCLC and HNSCC. Clinical trial registration ClinicalTrials.gov NCT02020577 .

The 'Competing interests' statement of this Article has been updated; please see the accompanying Amendment. The original Article has not been corrected online.

e14150 Background: Over the past decade, a better understanding of cancer biology has led to a revolution in immunotherapy. Checkpoint inhibitors (ICI), bispecific antibodies and agonistic agents have shown benefit in cancer treatment. Unfortunately, not all patients benefit and, despite the advances achieved in discovering markers of response, the selection of patients can still be challenging in everyday practice. Methods: We conducted a retrospective analysis of potential prognostic and predictive factors of survival in a cohort of 186 patients enrolled into Phase I Trials testing immunotherapeutic agents at our institution. We computed univariate and multivariate analysis (MVA) of demographics, clinical and molecular characteristics to assess their prognostic and predictive potential of clinical benefit (defined as achieving Complete or Partial Response (CR/PR) as best response or disease stabilization lasting > 120 days) and survival. Molecular testing included Next Generation Sequencing (NGS - Oncomine Comprehensive Assay) grouped in DNA repair, Transcription regulation, Signal Transduction and Cell-Cell interaction pathways. Results: A total of 186 patients (Male/Female: 81/105; median age 61yo) received treatment with either immune checkpoint inhibitors (122 (65,6%)), checkpoint agonists (37 (19.9%)); bispecific antibodies (19 (10.21%) or other immunotherapies (8 (4.29%)) between November 2015 and July 2018. Royal Marsden Score (RMH) was assessed and correlated with progression free survival and overall survival in the total cohort. Median Overall Survival (mOS) was 422 days (CI95%: 345-500 days), 387 (CI95%: 297-478 days), 235 (CI95%: 131-338 days), and 167 (CI95% 64-270 days) for RMH 0, 1, 2 and 3, respectively (p = 0.007). Among 57 patients with NGS results, those with pathogenic mutations in DNA repair pathways (n = 26) showed a trend towards a higher response rate (69% vs 30% p = 0.064) and clinical benefit (65% vs 35%; p = 0.034). Conclusions: Alterations in DNA repair pathways are a potential predictor of benefit of immunotherapy and warrants further studies. A larger cohort of patients is currently being explored in our center to further validate these findings.

6069 Background: New therapeutic approaches are needed for elderly or frail head and neck squamous cell carcinoma (HNSCC) patients (pts) ineligible for standard of care treatment. NBTXR3, a crystalline solution of hafnium oxide nanoparticles may represent such an option. Injected intratumorally, NBTXR3 enters tumor cells and yields an increased cell-localized energy deposit upon exposure to radiotherapy (RT), leading to increased tumor cell death compared to the same dose of RT alone. Methods: Phase I study of NBTXR3 activated by RT in pts ≥70 years old or ≥65 years old and unable to receive cisplatin, eligible for exclusive RT with stage III or IV HNSCC of the oral cavity or oropharynx [NCT01946867]. A 3+3 dose escalation design was implemented with dose levels corresponding to 5%, 10%, 15% and 22% of baseline tumor volume, followed by an expansion phase. Pts received an intratumoral (IT) injection of NBTXR3 and intensity modulated RT (IMRT; 70 Gy/35 fractions/7 weeks). Determination of Recommended Phase 2 Dose (RP2D) and Dose Limiting Toxicities (DLT) were primary endpoints of phase I. Absence of NBTXR3 leakage and preliminary efficacy using RECIST 1.1 principles were also evaluated. Results: The dose-escalation is complete. Nineteen pts were enrolled: 3 at 5%, 3 at 10%; 5 at 15% and 8 at 22% with no observed DLT or SAE related to NBTXR3 or IT injection. One grade 1 NBTXR3-related AE (asthenia at 22%) and four IT injection-related AE (grade 2 oral pain; grade 1 tumor hemorrhage; grade 1 asthenia, and grade 1 injection site hemorrhage) were reported. RT-related toxicity was as expected with IMRT. RP2D has been determined to be 22%. CT-scan assessment between 24h and 7 weeks post-IT injection demonstrated absence of NBTXR3 leakage in the surrounding tissues. Among 13 evaluable pts treated at doses ≥10%, 9 achieved a complete response of the injected lesion. Conclusions: These results show that NBTXR3 activated by RT is safe and well tolerated at all doses with preliminary encouraging efficacy results. It thus represents a promising future treatment for frail and elderly pts with locally advanced HNSCC with limited therapeutic options. Expansion phase has started at the RP2D. Clinical trial information: NCT01946867.

TPS2667 Background: Eftilagimod alpha (efti, IMP321) is a recombinant LAG-3Ig fusion protein that binds to MHC class II and mediates antigen-presenting cell (APC) activation followed by CD8 T-cell activation. Pembrolizumab binds to the PD-1 receptor, blocking both immune-suppressing ligands, PD-L1 and PD-L2, from interacting with PD-1 to help restore effector T-cell responses. The rationale to combine efti and pembrolizumab comes from their complementary mechanisms of action. Efti activates APCs and lead to an increase in activated T cells which effect potentially reduces the number of non-responders to pembrolizumab. Combining an APC activator like efti to pembrolizumab is therefore fundamentally different from many other trials combining two checkpoint inhibitors like an anti-LAG-3 mAb with an anti-PD-1 mAb. In a previous phase I study (NCT 02676869) in metastatic melanoma the combination was found to be safe and well tolerable with encouraging signs of clinical activity. Methods: In the course of this multicenter, open label, Phase II study, patients will be recruited for each of three indications: A: 1st line, PD-X (PD-1 or PD-L1) naïve non-small cell lung cancer (NSCLC); B: 2nd line, PD-X refractory NSCLC; C: 2nd line PD-X naive head and neck squamous cell carcinoma (HNSCC). The study is designed according to Simon's optimal two-stage design, with objective response rate acc to iRECIST as primary endpoint. Secondary endpoints include progression free survival and overall survival. In case there are more responses achieved than a predefined threshold (each part counted separately) in pts recruited in the initial stage (n = 58), additional pts (51) will be recruited in stage 2. Efti will be administered for a maximum of 18 cycles (1 cycle = 3 weeks) as 30 mg subcutaneous injection every 2 weeks for the first 8 and every 3 weeks for the 10 following cycles. Pembrolizumab (200 mg intravenous infusion every 3 weeks) is administered in parallel for up to 35 cycles. Patients are followed up for progression and survival. Clinical trial information: 03625323.

TPS1101 Background: MEN1611 is a potent, selective class I inhibitor of PI3K, a key enzyme in the transduction of various extracellular growth factor signals essential for cell survival and apoptosis. The discovery in human cancers of frequent PIK3CA mutations, that have been linked to a worse outcome in advanced HER2-positive breast cancer, makes PI3K an attractive therapeutic target. Preclinical and clinical evidences support the development of MEN1611 in combination with other agents in the context of solid tumors. Methods: B-PRECISE-01 is an open-label, multicenter, phase Ib dose escalation study in patients with PIK3CA mutant tumors, HER2-positive advanced or metastatic breast cancer which has progressed after at least 2 lines of anti-HER2 based therapy. PIK3CA mutations are assessed centrally by real-time PCR assay in DNA derived from archived tumor samples. MEN1611 will be administered orally BID for continuous 28-day cycles until disease progression, in combination with weekly IV infusions of trastuzumab. In addition, HR-positive postmenopausal patients will also be treated with fulvestrant. After the completion of the dose escalation phase (Step 1), the study will continue in an expansion cohort (Step 2) testing the Recommended Phase 2 dose (RP2D) in a total of 15 patients in each of the treatment groups. The primary study objective is to assess combination safety and select RP2D. Secondary objectives include assessment of pharmacokinetics and pharmacodynamics, preliminary clinical activity of MEN1611 in combination with trastuzumab +/- fulvestrant, and correlation with PIK3CA mutations and other relevant cancer genes mutational status. Adverse events will be graded according to NCI CTCAE v4.03. Responses will be evaluated according to RECIST v1.1. Study variables will be presented by dose-cohort and overall using appropriate descriptive statistics. The enrollment began in July 2018 at European sites and US sites will shortly participate; up to date the first dose cohort level has been achieved. Clinical trial information: NCT03767335.

TPS5087 Background: Assessing multiple therapies in a single clinical trial can facilitate the rapid identification of new agents for the treatment of patients with metastatic castration-resistant prostate cancer (mCRPC). Niraparib (Nirap) is a highly selective PARP inhibitor, with potent activity against PARP-1 and PARP-2 deoxyribonucleic acid (DNA)-repair polymerases. PARP inhibition may be especially lethal in tumor cells with genetic DNA damage response deficits (DRD). Based on promising preclinical and clinical data, this study is designed as a master protocol with nirap as a backbone therapy. Combination 1 assesses the safety and efficacy of nirap plus JNJ-63723283 (JNJ-283), an anti-PD-1 monoclonal antibody. Combination 2 assesses nirap plus abiraterone acetate and prednisone (AA-P). Methods: This multicenter, global, open-label study is currently open at 18 sites in 5 countries of the planned XX sites, and is enrolling patients with mCRPC who have progressed on ≥1 androgen-receptor targeted therapy for mCRPC. Enrollment at time of abstract submission was 25 for combination 1. When combined with AA-P, the RP2D has been determined to be nirap 200 mg. The recommended phase-2 dose (RP2D) of nirap plus JNJ-283 was determined in Part 1 based on the incidence of specified adverse events and PK data to be 480 mg every 4 weeks. For Part 2 of the study, patients are assigned to receive oral niraparib daily plus JNJ-283 infusions once every four weeks until disease progression, unacceptable toxicity, death, study termination. Part 2 is described in the table. Clinical trial information: NCT03431350. [Table: see text]

8570Background: SCLC is a deadly cancer and despite initial 80% response, almost all patients (pts) will relapse and die of this disease. Limited options exist after failure of first line, with a m...

1072Background: PM1183 (lurbinectedin, Zepsyre) is a new anticancer drug that blocks transcription, induces DNA double-strand breaks, and modulates the tumor microenvironment. Single-agent PM1183 h...

BACKGROUND: MCLA-128 is a novel humanized full length IgG1 bispecific antibody with enhanced antibody-dependent cell-mediated cytotoxicity (ADCC) activity that targets the transmembrane tyrosine kinase receptors, HER2 and HER3 present on a variety of epithelial tumor cells. In preclinical studies, MCLA-128 demonstrated potent anti-tumor activity. The primary objectives of this First-in-Human (FIH) study are to establish the MTD and Phase 2 recommended dose (RP2D) of MCLA-128 and to assess its safety, tolerability, PK, PD, and anti-tumor activity in selected patient (pt) groups. METHOD: The trial consists of 2 parts. In Part 1 (dose-escalation) patients (pts) with advanced epithelial tumors with no standard management options were enrolled with an initial accelerated 1 pt per cohort design shifting to a 3 + 3 design. The DLT evaluation period was 21 days ( = 1 cycle). MCLA-128 was administered every 3 weeks (q3w) as an intravenous infusion over 60-120 minutes. Toxicities were assessed throughout dose escalation (40 mg up to 900 mg flat dose). Part 2 consists of several expansion cohorts of pts at the RP2D (expansion phase). Here we present interim results for Part 1 of the study. RESULTS: Twenty-eight pts received MCLA-128 in 9 dose-escalation cohorts (40-160 mg in cohorts of 1 evaluable pt, 240-900 mg in cohorts of 3 to 6 evaluable pts). The most frequent drug related adverse events (AEs) observed in Part 1 were mild to moderate (G1-G2) with prompt recovery in general. AEs included infusion-related reactions (IRR), diarrhea, nausea, vomiting, fatigue, maculopapular rash, oral mucositis and G2 neutropenia in 1 pt. IRR occurred in 50% of pts with a trend for increased incidence with dose; modest and transient dose dependent cytokine release was also observed. Increasing the infusion duration to 120 min and premedication with corticosteroids was successfully implemented to mitigate IRRs and cytokine levels were no longer correlative with MCLA-128 dose levels. One drug related serious AE (SAE) has been reported: IRR G3, due to prolonged hospitalization (SUSAR). No DLTs were observed. In serum samples from 12 pts, 1 pt was positive for MCLA-128 anti-drug antibodies 36 days after starting treatment at a dose of 160 mg. A MTD was not reached in the study; PK analysis was used to support a RP2D of 750 mg q3w. Exposure to MCLA-128 increased in proportion to dose. The RP2D was calculated to maintain trough concentrations at the end of each treatment cycle significantly above the Kd of MCLA-128 as determined on HER2 amplified cell lines in vitro and above the Km in a population PK model. Preliminary signs of anti-tumor activity assessed by RECIST are encouraging. Three pts remain on study to date including 1 non-small-cell lung cancer pt who is experiencing an ongoing partial response for more than 10 months, 1 gastroesophageal junction pt and 1 colorectal cancer pt with stable disease for 5 months. In addition, 1 metastatic breast cancer pt received 5 months of MCLA-128 treatment until disease progression. CONCLUSION: MCLA-128 was well-tolerated with a favorable safety profile in pts with advanced tumors treated at doses up to 900 mg q3w. PK results and preliminary signs of anti-tumor activity support the further clinical evaluation of MCLA-128 at the RP2D of 750 mg q3w. The expansion phase of the study is ongoing at this dose level. Citation Format: Emiliano Calvo, Maria Alsina, Jan H.M. Schellens, Alwin DR Huitema, Josep Tabernero, Aurelia de Vries-Schultink, Valentina Boni, Bernard Doger, Cecile Geuijen, Robert Doornbos, Kees Bol, Martine Westendorp, Mark Throsby, Lex Bakker, Setareh Shamsili. A Phase I/II Study of MCLA-128, a full length IgG1 Bispecific Antibody Targeting HER2 and HER3, in Patients with Solid Tumors. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr CT050.