Abstract: Introduction: Patients (pts) with acute myeloid leukemia (AML) who are refractory to intensive frontline treatment have a dismal outcome. In case of ineligibility for allogeneic stem cell transplantation (HSCT), the median survival of chemo-refractory AML is about 2 months and less than 5% of these pts are alive after 1-year (retrospective analysis from the AMLSG database). To date, there is no universally accepted standard approach for the treatment of chemo-refractory AML in older pts. Several retrospective studies have assessed the role of hypomethylating agents in this patient group, but complete remission (CR) rates were disappointingly low (≤10%) when compared to first line treatment. The presented study represents a novel approach focusing on hematopoietic tissue reprogramming (i.e. anakoinosis) (ClinicalTrials.gov Identifier: NCT02942758). Methods: The initial dose-finding phase I of the study evaluated the combination of azacitidine (AZA) 75 mg/d s.c. for 7 days, repeated every 28-days, pioglitazone 45 mg/d p.o. continuously from day 1 and all-trans retinoic acid (ATRA). A modified 3+3 design has been used to establish the maximum-tolerated dose of ATRA. Patients have been enrolled at an ATRA dose of 45 mg/m²/d from day 1 to day 28 and 15 mg/m²/d continuously thereafter if no dose limiting toxicity (DLT) occurred until start of next cycle on day 29. The safety DLTs were defined as toxicities attributable to ATRA, expected or unexpected, except if these are likely associated with another cause. Eligible patients had confirmed diagnosis of AML refractory to induction therapy and were not eligible for further intensive induction therapy or were not immediate candidates for allogeneic HSCT. The severity of adverse events was graded using the Common Terminology Criteria for Adverse Events (CTCAE) V. 4.03. The response to treatment was evaluated using standard criteria defined by the expert panel on behalf of the European LeukemiaNet and international working group (IWG) response. Results: Ten pts were enrolled in the safety-run-in phase I (one pt withdrew informed consent on day 9 of cycle 1). Among all treated pts, the median age was 67 years (range, 62-76 years), and the majority of pts (70%) had an ECOG PS of 1 (see table 1). Two pts had secondary AML; another two pts had therapy-related AML (t-AML). Eight pts had a complex karyotype. Concerning safety, hematological adverse events (AEs) were the most common toxicities observed. Because pts with baseline cytopenia were included (leukopenia n=8; 80%; thrombocytopenia n=9; 90%), occurrences of many hematological AEs began before study drug initiation and were attributed to underlying hematologic disease. Common 3°/4° AEs included neutropenia (50%), anemia (50%), thrombocytopenia (30%), and infections (40%). 50% of pts experienced a serious AE; one 5° AE (gastric hemorrhage) occurred. No DLTs were observed. Five pts discontinued the study, with progressive disease (PD) or relapse being the most common reason for discontinuation. Concerning efficacy, 3 pts (30%) achieved a CR and one pt a long-lasting stable disease (14 months). Morphologic review showed signs of differentiation of blasts in responding pts, which has already been shown in in-vitro analysis. In line with this observation, one pt demonstrated resolution of fungal pneumonia during the study. Conclusions: In summary, the low-intensity, biomodulatory regimen of low-dose AZA, pioglitazone, and ATRA demonstrated a tolerable safety profile and encouraging signals for efficacy in pts with AML refractory to standard induction chemotherapy warranting further investigation. S.T. and A.R. contributed equally to this abstract as senior co-authors. Disclosures Paschka: Novartis: Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses, Speakers Bureau; Astellas: Membership on an entity's Board of Directors or advisory committees; Agios: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees, Other: Travel expenses, Speakers Bureau; Abbvie: Other: Travel expenses; Amgen: Other: Travel expenses; Otsuka: Membership on an entity's Board of Directors or advisory committees; BMS: Other: Travel expenses, Speakers Bureau; Astex: Membership on an entity's Board of Directors or advisory committees, Travel expenses; Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Jazz: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Other: Travel expenses; Takeda: Other: Travel expenses; Sunesis: Membership on an entity's Board of Directors or advisory committees. Döhner:Celgene, Novartis, Sunesis: Honoraria, Research Funding; AROG, Bristol Myers Squibb, Pfizer: Research Funding; AbbVie, Agios, Amgen, Astellas, Astex, Celator, Janssen, Jazz, Seattle Genetics: Consultancy, Honoraria. Thomas:Celgene: Consultancy, Other: Travel support, Research Funding, Speakers Bureau; Gilead: Membership on an entity's Board of Directors or advisory committees, Other: Travel support; Medigene AG: Consultancy, Other: Travel support; Novartis: Membership on an entity's Board of Directors or advisory committees, Other: Travel support, Speakers Bureau; Pfizer: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Medac: Other: Travel support; Janssen: Other: Travel support.

Abstract: 2518 Background: We are developing a chimeric antigen receptor (CAR)-T cell therapy targeting claudin 6 (CLDN6), an oncofetal antigen that is undetectable in healthy somatic tissue and highly expressed in various solid cancers. Autologous CLDN6 CAR-T cells are being tested alone and in combination with CLDN6-encoding CAR-T cell Amplifying RNA Vaccine (CARVac), a nanoparticulate RNA vaccine designed to stimulate and expand CLDN6 CAR-T cells. Methods: The ongoing first-in-human trial BNT211-01 evaluates the safety and feasibility of CLDN6 CAR-T cell transfer ± CARVac in lymphodepleted patients with relapsed/refractory solid tumors. Patients are pre-screened for CLDN6 expression with a cut-off of 50% positivity of intermediate or strong intensity by immunohistochemistry staining. Key endpoints are safety, tolerability, and anti-tumor activity. Pharmacokinetics of adoptively transferred CAR-T cells in peripheral blood is monitored by quantitative PCR. Dose escalation proceeds according to a classical 3+3 design, testing CLDN6 CAR-T cells at each dose level as both as monotherapy and in combination with CARVac. We previously reported results from 22 patients from 4 dose escalation cohorts with a manual CAR-T production process ± CARVac (ESMO-IO LBA38) which followed the same methodology. We observed durable responses along with a manageable safety profile, in line with commercial CAR-T products used to treat B-cell malignancies. No on-target/off-tumor toxicity and only a single case of (grade 1) neurotoxicity was observed. Given the encouraging efficacy, we have implemented an automated process to scale-up manufacturing. Accordingly, we are repeating the dose escalation with an automated CAR-T cell product, and with a modified CARVac regimen. As of 1 st February 2023, 7 patients with epithelial ovarian carcinoma (EOC), 4 with testicular germ cell tumors (GCT), and a further 5 patients with tumors of various indications have been infused with CAR-T cells up to DL2. We intend to submit efficacy, safety and CAR T-cell pharmacokinetics data from 5 cohorts treated with 1x10 6 , 1x10 7 or 1x10 8 CLDN6 CAR-T cells ± CARVac with a data cut-off of March 14 th , 2023 from ≥17 treated patients as a late-breaking abstract. Clinical trial information: NCT04503278 .

Abstract: Background: Most non-small cell lung cancers occur in elderly and frequently comorbid patients. Therefore, it is necessary to evaluate the efficacy of biomodulatory active therapy regimen, concertedly interfering with tumor-associated homeostatic pathways to achieve tumor control paralleled by modest toxicity profiles. Patients and Methods: The ModuLung trial is a national, multicentre, prospective, open-label, randomized phase II trial in patients with histologically confirmed stage IIIB/IV squamous ( n = 11) and non-squamous non-small cell ( n = 26) lung cancer who failed first-line platinum-based chemotherapy. Patients were randomly assigned on a 1:1 ratio to the biomodulatory or control group, treated with nivolumab. Patients randomized to the biomodulatory group received an all-oral therapy consisting of treosulfan 250 mg twice daily, pioglitazone 45 mg once daily, clarithromycin 250 mg twice daily, until disease progression or unacceptable toxicity. Results: The study had to be closed pre-maturely due to approval of immune checkpoint inhibitors (ICi) in first-line treatment. Thirty-seven patients, available for analysis, were treated in second to forth-line. Progression-free survival (PFS) was significantly inferior for biomodulation ( N = 20) vs. nivolumab ( N = 17) with a median PFS (95% confidence interval) of 1.4 (1.2–2.0) months vs. 1.6 (1.4–6.2), respectively; with a hazard ratio (95% confidence interval) of 1.908 [0.962; 3.788]; p = 0.0483. Objective response rate was 11.8% with nivolumab vs. 5% with biomodulation, median follow-up 8.25 months. The frequency of grade 3–5 treatment related adverse events was 29% with nivolumab and 10% with biomodulation. Overall survival (OS), the secondary endpoint, was comparable in both treatment arms; biomodulation with a median OS (95% confidence interval) of 9.4 (6.0–33.0) months vs. nivolumab 6.9 (4.6–24.0), respectively; hazard ratio (95% confidence interval) of 0.733 [0.334; 1.610]; p = 0.4368. Seventy-five percent of patients in the biomodulation arm received rescue therapy with checkpoint inhibitors. Conclusions: This trial shows that the biomodulatory therapy was inferior to nivolumab on PFS. However, the fact that OS was similar between groups gives rise to the hypothesis that the well-tolerable biomodulatory therapy may prime tumor tissues for efficacious checkpoint inhibitor therapy, even in very advanced treatment lines where poor response to ICi might be expected with increasing line of therapy.

Abstract: Background: BNT211 comprises two drug products, a chimeric antigen receptor (CAR)-T cell product candidate that targets the tumor specific antigen claudin 6 (CLDN6) and a CAR-T cell-Amplifying RNA Vaccine (CARVac). In mice, CARVac mediates expansion of adoptively transferred CAR-T cells, improving their persistence and functionality. BNT211 aims to establish CAR-T cell therapy for CLDN6-positive solid tumors. Methods: This first-in-human, open label, multi-center trial involves a bifurcated 3+3 design with CLDN6 CAR-T cell dose escalations for both monotherapy (Part 1) and combination with CARVac (Part 2) following lymphodepletion. In Part 2, CARVac is applied q2/3w up to 100 days post CAR-T cell transfer, including a one-step intra-patient dose escalation followed by q6w maintenance dosing. Patients with CLDN6-positive relapsed or refractory solid tumors without further standard treatment options and ECOG 0-1 are eligible for recruitment. Results: As of 19th Jan 2022, 16 patients have been treated, with CAR-T cell transfer performed at dose levels (DLs) 1 and 2 for parts 1 and 2. In total, 37 ≥G3 AEs related to the drug product (mainly cytopenia, or transaminase and lipase elevations without clinical correlates) and 2 DLTs (G4 cytopenia at DL2, part 1 and G4 hemophagocytic lymphohistiocytosis at DL2, part 2) were reported (all resolved). Pronounced cytopenia occurred in patients with testicular cancer who had recently received high-dose chemotherapy and autologous stem cell transplantation. For these patients a lymphodepletion-free/reduced cohort was recently opened. Analysis of CAR-T cell frequency in peripheral blood revealed robust engraftment in all patients, with peak engraftment around day 17. Manageable cytokine release syndrome (G1-2) without any signs of neurotoxicity was observed in 8 patients. Administration of CARVac resulted in transient flu-like symptoms resolving within 24 h. Preliminary efficacy data of 12 evaluable patients 6 weeks after infusion showed 5 patients with PRs (with 39-49% shrinkage of target lesions), 6 with SD and 1 patient with PD (ORR 42%; DCR 92%), with responses seen in testicular and ovarian cancer patients. At 12 weeks, 5 of the 6 patients with PRs showed deepening of responses (50-73% shrinkage). In addition, one testicular cancer patient was treated with a 50% lymphodepletion regime and showed PR after 6 weeks. Conclusions: CLDN6 CAR-T cells ± CARVac show an acceptable safety profile at doses tested and encouraging signs of clinical activity. Data from the completed dose escalation phase will be presented. Acknowledgements: BNT211-01 is funded by BioNTech Cell & Gene Therapies GmbH. Trial registration: Clinicaltrials.gov: NCT04503278. Ethics approval: Ethics & Institutional Review Board approvals were obtained from the respective participating countries prior to initiation of the trial. Citation Format: John BAG Haanen, Andreas Mackensen, Christian Koenecke, Winfried Alsdorf, Eva Wagner-Drouet, Daniel Heudobler, Peter Borchmann, Carsten Bokemeyer, Sebastian Klobuch, Alexander Desuki, Florian Lüke, Erol Wiegert, Catrine Schulz, Benjamin Rengstl, Liane Preussner, Özlem Türeci, Ugur Sahin. BNT211: A Phase I trial to evaluate safety and efficacy of CLDN6 CAR-T cells and CARVac-mediated in vivo expansion in patients with CLDN6-positive advanced solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr CT002.