Fonkoua, Lionel Aurelien Kankeu

539 Background: Tinengotinib is a spectrum-selective multi-kinase inhibitor with a unique FGFR-binding mechanism. It potently inhibits FGFR2 fusion/rearrangement and acquired resistant mutations in pre-clinical models and early clinical studies in cholangiocarcinoma (CCA). Here we present the preliminary efficacy and safety of tinengotinib (TT-00420) in a phase II trial TT420C1206 (NCT04919642). Methods: Eligible patients (pts) with advanced/metastatic CCA exhausting standard treatment options received tinengotinib 10 mg QD. Pts were enrolled into four cohorts using historical FGFR alteration status: FGFR2 fusion(s) with primary progression on previous FGFR inhibitor (FGFRi) (A1) or progression after prior response to FGFRi (acquired resistance) (A2); non-fusion FGFR alteration(s) (B); or FGFR wild-type (FGFRwt, C). Primary endpoint was objective response rate (ORR) per RECIST version 1.1. Safety, PK parameters, and biomarker profile were evaluated and reviewed jointly with the efficacy outcomes. Adverse events (AEs) were graded per CTCAE version 5.0. Results: As of Sep 13, 2022, 25 pts with CCA were enrolled and dosed; 7 in A1, 6 in A2, 2 in B and 10 in C. Median age 61 [range 24-82] years old, 64% female, 93.3% had ≥ 3 prior treatment lines. 13 patients with ECOG 0 and 12 patients with ECOG 1 at baseline. Among 15 patients with historical FGFR alterations (13 fusions/rearrangement and 2 mutations), 93.3% had ≥ 1 prior FGFRi, and 3 pts (20.0%) had 2 prior FGFRi treatments. Eighteen pts were evaluable for tumor assessment at data cutoff date, including 4 in A1, 6 in A2, 1 in B and 7 in C. The median follow up was 15 weeks. In A2, 2 out of 6 pts (33%) achieved PR with tumor reductions of 34% and 54%. Overall DCR (CR or PR+SD) was 90% (9/10) in FGFR2 fusion/rearrangement pts; 100% in FGFR primary mutation pt (1/1); and 71% (5/7) in FGFRwt pts. One PR and 5 SDs lasted for more than 16 weeks. Among 25 treated pts, drug-related AEs occurred in 20 (80%) pts, including 7 (28%) with Grade (G) 1-2 AEs, 12 (48%) with G3 AEs, and 1 (4%) with G4 AE. Most frequently occurred G3/4 AEs were hypertension in 6 (24%) pts, including 5 (20%) with G3 and 1 (4%) with G4, G3 fatigue in 2 (8%) and G3 neutrophil count decreased in 2 (8%) pts. No drug-related G5 was observed. The efficacy and safety results observed were consistent with the previous reported data ( NCT03654547 ) in CCA pts. The preliminary biomarker analysis suggests loss of resistant FGFR mutation on liquid biopsy post tinengotinib therapy. Further biomarker analysis will be updated at the presentation. Conclusions: Tinengotinib may result in promising clinical benefit for CCA pts in the setting of FGFRi-resistance. Tinengotinib-related toxicities were manageable. An ongoing phase II study will further provide safety, efficacy and biomarker evaluations for both FGFR resistant and FGFRwt CCA. Clinical trial information: NCT04919642 .

ImportanceApproval by the US Food and Drug Administration of immune checkpoint inhibition (ICI) for advanced gastroesophageal cancer (aGEC) irrespective of PD-L1 status has generated controversy. Exploratory analyses from individual trials indicate a lack of meaningful benefit from ICI in patients with absent or low PD-L1 expression; however, analysis of a single variable while ignoring others may not consider the instability inherent in exploratory analyses.ObjectiveTo systematically examine the predictive value of tissue-based PD-L1 status compared with that of other variables for ICI benefit in aGEC to assess its stability.Data SourcesMEDLINE, Embase, Scopus, Web of Science, Cochrane Central Register (2000-2022).Study Selection, Data Extraction, and SynthesisRandomized clinical trials (RCTs) were included of adults with aGEC (adenocarcinoma [AC] or squamous cell carcinoma [SCC]) randomized to anti−PD-1 or PD-L1−containing treatment vs standard of care (SOC). Study screening, data abstraction, and bias assessment were completed independently by 2 reviewers. Of 5752 records screened, 26 were assessed for eligibility; 17 trials were included in the analysis.Main Outcomes and MeasuresThe prespecified primary end point was overall survival. The mean hazard ratio (HR) for ICI vs SOC was calculated (random-effects model). Predictive values were quantified by calculating the ratio of mean HRs between 2 levels of each variable.ResultsIn all, 17 RCTs (9 first line, 8 after first line) at low risk of bias and 14 predictive variables were included, totaling 11 166 participants (5067 with SCC, 6099 with ACC; 77.6% were male and 22.4% were female; 59.5% of patients were younger than 65 years, 40.5% were 65 years or older). Among patients with SCCs, PD-L1 tumor proportion score (TPS) was the strongest predictor of ICI benefit (HR, 0.60 [95% CI, 0.53-0.68] for high TPS; and HR, 0.84 [95% CI, 0.75-0.95] for low TPS), yielding a predictive value of 41.0% favoring high TPS (vs ≤16.0% for other variables). Among patients with AC, PD-L1 combined positive score (CPS) was the strongest predictor (after microsatellite instability high status) of ICI benefit (HR, 0.73 [95% CI, 0.66-0.81] for high CPS; and HR, 0.95 [95% CI, 0.84-1.07] for low CPS), yielding a predictive value of 29.4% favoring CPS-high (vs ≤12.9% for other variables). Head-to-head analyses of trials containing both levels of a variable and/or having similar design generally yielded consistent results.Conclusions and RelevanceTissue-based PD-L1 expression, more than any variable other than microsatellite instability-high, identified varying degrees of benefit from ICI-containing therapy vs SOC among patients with aGEC in 17 RCTs.

Abstract Pivotal clinical trials of B-cell maturation antigen-targeted chimeric antigen receptor T (CART)-cell therapy in patients with relapsed/refractory multiple myeloma (MM) resulted in remarkable initial responses, which led to a recent US Food and Drug Administration approval. Despite the success of this therapy, durable remissions continue to be low, and the predominant mechanism of resistance is loss of CART cells and inhibition by the tumor microenvironment (TME). MM is characterized by an immunosuppressive TME with an abundance of cancer-associated fibroblasts (CAFs). Using MM models, we studied the impact of CAFs on CART-cell efficacy and developed strategies to overcome CART-cell inhibition. We showed that CAFs inhibit CART-cell antitumor activity and promote MM progression. CAFs express molecules such as fibroblast activation protein and signaling lymphocyte activation molecule family-7, which are attractive immunotherapy targets. To overcome CAF-induced CART-cell inhibition, CART cells were generated targeting both MM cells and CAFs. This dual-targeting CART-cell strategy significantly improved the effector functions of CART cells. We show for the first time that dual targeting of both malignant plasma cells and the CAFs within the TME is a novel strategy to overcome resistance to CART-cell therapy in MM.

Abstract With the development of various strategies of anti-CD19 immunotherapy for treatment of B cell malignancies, it remains to be elucidated whether CD19 targeting with a monoclonal antibody impairs subsequent CD19 targeted chimeric antigen receptor T cell (CART19) therapy. In this study, we evaluated the potential interference between the CD19 targeting monoclonal antibody tafasitamab and CART19 treatment (using a construct similar to the FDA approved therapy, FMC63-41BBζ, tisagenlecleucel) in preclinical lymphoma and leukemia models. For in vitro assays, the CD19 + cell lines JeKo-1 (mantle cell lymphoma), Nalm6 (acute lymphoblastic leukemia), and OCI-Ly7 (diffuse large B cell lymphoma) were used. When CART19 were co-cultured with CD19 + tumor cells in the presence of increasing concentrations of tafasitamab (10-400 µg/mL) or the isotype control, an impairment of CART19 functions at the highest concentration of tafasitamab was observed. However, when tafasitamab was cocultured with tumor cells overnight and removed from the culture by washing, there was no impairment of CART19 anti-tumor activity or effector functions compared to a pre-culture with isotype control. We then aimed to validate these findings in xenograft mouse models by determining whether prior tafasitamab treatment impairs subsequent CART cell function. First, a two-step JeKo-1 xenograft model was created through inoculation of 1x10 6 luciferase + JeKo-1 cells to immunocompromised NOD-SCID-γ -/- (NSG) mice via tail vein injection. One week later, tumor burden was assessed by bioluminescence imaging (BLI) and mice were randomized to receive either 1) PBS (Group 1) or 2) 10 mg/kg of tafasitamab (Group 2) (Fig. 1A). Treatment was performed until the mice reached the endpoint due to the high tumor load. When reaching the endpoint, mice were euthanized and spleen was harvested. Splenic cells were then injected to naïve NSG mice. Two weeks after the inoculation of splenic cells (PBS or tafasitamab treated), mice were imaged with BLI and randomized according to their tumor burden to receive 2x10 6 of 1) untransduced T cells (UTD) or 2) CART19 (i.v.) (Fig. 1B). Mice, treated with CART19 demonstrated potent anti-tumor effects and showed prolonged survival compared to UTD control mice. Interestingly, CART19-treated mice inoculated with Group 2 splenic cells (pretreated with tafasitamab) showed a significantly better tumor control and overall survival compared with mice engrafted Group 1 splenic cells (PBS pretreatment) (Fig. 1C). This finding led us to further investigate the effects of prior tafasitamab therapy on subsequent CART19 treatment. In this context, we studied the sequential treatment with tafasitamab and CART19 in an additional JeKo-1 xenograft model (Fig. 1D). In brief, NSG mice were inoculated with luciferase + JeKo-1 on day -14. On day -8, mice were imaged and randomized to the PBS (Group I) or tafasitamab (10 mg/kg) group. On day -1 tafasitamab treated mice were imaged again, randomized to the tafasitamab discontinuation (Group II) or continuation (Group III). Treatment with PBS was continued in Group I. All groups were administered with 1x10 6 of CART19 on day 0. Cotreatment of JeKo-1 xenografts with tafasitamab and CART19 led to impaired anti-tumor activity presumably as a result of CD19 binding competition between tafasitamab and CART19 (Group III). Mice treated with tafasitamab followed by CART19 had improved tumor control compared to mice treated with PBS followed by CART19 (Fig. 1E-F). Serial peripheral blood analysis demonstrated that mice from Group I showed the highest CART19 expansion on day 10. Strikingly, Group II exhibited weak CART19 expansion at day 10, but strongest expansion on day 23 (Fig. 1G). We therefore hypothesized that prior treatment with tafasitamab results in modulation of CART19 cell activation. To test this hypothesis, spleens of satellite mice were harvested 24 hours after CART19 administration. Flow cytometric analysis revealed that the mice from Group II showed significantly lower CD69 and HLA-DR expression on CART19 cells compared with Group I, and reduced apoptosis as measured by the Annexin assay (Fig. 1H-I). In summary, concomitant treatment of tafasitamab and CART19 led to impaired anti-tumor activity while, in contrast, sequential treatment of tafasitamab and CART19 did not inhibit CART19 anti-tumor activity but rather promoted anti-tumor effects in xenograft models. Figure 1 Figure 1. Disclosures Sakemura: Humanigen: Patents & Royalties. Augsberger: MorphoSys AG: Current Employment. Schanzer: MorphoSys AG: Current Employment. Patra-Kneuer: MorphoSys AG: Current Employment. Heitmüller: MorphoSys AG: Current Employment. Steidl: MorphoSys AG: Current Employment. Endell: MorphoSys AG: Current Employment. Ding: DTRM: Research Funding; Merck: Membership on an entity's Board of Directors or advisory committees, Research Funding; Octapharma: Membership on an entity's Board of Directors or advisory committees. Parikh: Pharmacyclics, MorphoSys, Janssen, AstraZeneca, TG Therapeutics, Bristol Myers Squibb, Merck, AbbVie, and Ascentage Pharma: Research Funding; Pharmacyclics, AstraZeneca, Genentech, Gilead, GlaxoSmithKline, Verastem Oncology, and AbbVie: Membership on an entity's Board of Directors or advisory committees. Kay: Acerta Pharma: Research Funding; Targeted Oncology: Membership on an entity's Board of Directors or advisory committees; Oncotracker: Membership on an entity's Board of Directors or advisory committees; Juno Therapeutics: Membership on an entity's Board of Directors or advisory committees; Morpho-sys: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Dava Oncology: Membership on an entity's Board of Directors or advisory committees; TG Therapeutics: Research Funding; Behring: Membership on an entity's Board of Directors or advisory committees; CytomX Therapeutics: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Rigel: Membership on an entity's Board of Directors or advisory committees; MEI Pharma: Research Funding; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol Meyer Squib: Membership on an entity's Board of Directors or advisory committees, Research Funding; Tolero Pharmaceuticals: Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees; Agios Pharm: Membership on an entity's Board of Directors or advisory committees; Genentech: Research Funding; Sunesis: Research Funding. Nowakowski: Celgene, NanoString Technologies, MorphoSys: Research Funding; Celgene, MorphoSys, Genentech, Selvita, Debiopharm Group, Kite/Gilead: Consultancy, Membership on an entity's Board of Directors or advisory committees. Cox: Humanigen: Patents & Royalties. Kenderian: Humanigen, Inc.: Consultancy, Honoraria, Research Funding.

Abstract CD19-targeted chimeric antigen receptor T cell (CART19) therapy has been remarkably successful in treating a subset of patients with hematological malignancies. However, it is associated with significant toxicities, including cytokine release syndrome (CRS) and neurotoxicity (NT). Furthermore, the rate of durable responses after CART19 therapy is low, and most patients develop resistance to the therapy. One of the predominant mechanisms for CART cell resistance is intrinsic T cell dysfunction which leads to a suboptimal CART product. The Bruton's tyrosine kinase (BTK) inhibitor ibrutinib has been shown to favorably modulate CART phenotype and function through downregulation of inhibitory receptors and enhancement of CART cell efficacy in preclinical models and early clinical studies. However, ibrutinib is an irreversible receptor tyrosine kinase (RTK) inhibitor, and thus there are concerns that it inhibits CART cell proliferation and expansion. In contrast to ibrutinib and other BTK inhibitors, vecabrutinib has recently emerged as a potent, reversible, non-covalent BTK inhibitor that can block the activity of both wild type and C481 mutant BTK as well as interleukin-2-inducible T-cell kinase (ITK). We hypothesized that treatment with vecabrutinib improves CART19 antitumor efficacy through the reversible inhibition of BTK/ITK, independent of its antitumor effect. To test this hypothesis, we assessed whether vecabrutinib potentiates CART19 cytotoxicity against CD19 + tumor cells. Killing of the CD19 + mantle cell lymphoma cell line, JeKo-1, was significantly increased when CART19 were combined with vecabrutinib (Fig. 1A). Of note, vecabrutinib did not induce antitumor activity in this model as a single agent (Fig. 1A). In addition, vecabrutinib (10 µM) treatment of CART19 resulted in enhanced antigen-specific proliferation (Fig. 1B). Next, we aimed to study the direct impact of vecabrutinib on CART19 cytokine production. We measured the levels of multiple pro-inflammatory cytokines in the supernatant of CART19 co-cultured for 3 days with JeKo-1 cells and vecabrutinib. Vecabrutinib did not impair CART19 degranulation, as measured by flow cytometric assessment of CD107a expression (Fig. 1C). Cytokines known to play a crucial part in the development of CRS, such as IL-6, IL-10, and MIP-1β were significantly downregulated in cocultures with vecabrutinib (Fig. 1D-F). We then investigated whether the addition of vecabrutinib to CART19 caused a synergistic antitumor effect in vivo. We used our established JeKo-1 lymphoma xenograft models. Here NSG mice were engrafted with CD19 + luciferase + JeKo-1 cells. Mice were then imaged for engraftment and randomized to treatment with 1) untransduced control T cells, 2) CART19 with vehicle, or 3) CART19 with vecabrutinib 50 mg/kg BID administered via oral gavage over a period of 4 weeks. Vecabrutinib combination with CART19 treatment led to sustained antitumor activity (Fig.1G) and increased CART19 proliferation (Fig.1H). Encouragingly, mice treated with vecabrutinib better maintained their body weight following CART19 infusion, suggesting possibly dampened toxicity (Fig.1I). We also measured serum cytokine levels from patients on a phase 1 clinical trial (NCT03037645) testing vecabrutinib in B cell malignancies at baseline and four weeks after treatment. We found that vecabrutinib significantly reduces the levels of multiple pro-inflammatory cytokines linked to CART cell toxicity, including MIP-1β, IP-10, and TNF-a (Fig. 1J-L), further validating our preclinical findings. Finally, we interrogated the transcriptome of CART19 co-cultured with JeKo-1 with or without vecabrutinib. Total RNA sequencing of activated CART19 highlighted a significant enhanced expression of multiple genes involved in the PI3K/AKT and Th1 pathways compared to antigen stimulated CART19 alone (Fig.1M, N). These results could explain the enhanced proliferation and cytotoxicity induced by vecabrutinib. In summary, we demonstrate for the first time that using the reversible BTK inhibitor, vecabrutinib, is a potent and a novel strategy to favorably modulate CART19 function by increasing their efficacy and decreasing toxicity. Further studies are currently underway to compare the effect of reversible versus irreversible BTK/ITK inhibition on CART functions and to further validate the mechanisms responsible for the observed effects. Figure 1 Figure 1. Disclosures Sakemura: Humanigen: Patents & Royalties. Cox: Humanigen: Patents & Royalties. Fox: Sunesis Pharmaceuticals: Current Employment. Ding: Merck: Membership on an entity's Board of Directors or advisory committees, Research Funding; Octapharma: Membership on an entity's Board of Directors or advisory committees; DTRM: Research Funding. Parikh: Pharmacyclics, MorphoSys, Janssen, AstraZeneca, TG Therapeutics, Bristol Myers Squibb, Merck, AbbVie, and Ascentage Pharma: Research Funding; Pharmacyclics, AstraZeneca, Genentech, Gilead, GlaxoSmithKline, Verastem Oncology, and AbbVie: Membership on an entity's Board of Directors or advisory committees. Kay: MEI Pharma: Research Funding; Sunesis: Research Funding; Rigel: Membership on an entity's Board of Directors or advisory committees; AstraZeneca: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; CytomX Therapeutics: Membership on an entity's Board of Directors or advisory committees; TG Therapeutics: Research Funding; Juno Therapeutics: Membership on an entity's Board of Directors or advisory committees; Bristol Meyer Squib: Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Behring: Membership on an entity's Board of Directors or advisory committees; Genentech: Research Funding; Morpho-sys: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees, Research Funding; Targeted Oncology: Membership on an entity's Board of Directors or advisory committees; Tolero Pharmaceuticals: Research Funding; Dava Oncology: Membership on an entity's Board of Directors or advisory committees; Acerta Pharma: Research Funding; Agios Pharm: Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Oncotracker: Membership on an entity's Board of Directors or advisory committees. Kenderian: Humanigen, Inc.: Consultancy, Honoraria, Research Funding.