COPANLISIB SYNERGIES WITH CONVENTIONAL AND TARGETED AGENTS INCLUDING VENETOCLAX IN PRECLINICAL MODELS OF B‐ AND T‐CELL LYMPHOMAS

Abstract

Introduction: Copanlisib has shown activity in lymphomas, but the number of patients achieving complete remission is relatively low, a problem shared by many targeted agents. We performed a pharmacological screening to identify active combinations. Methods: We tested copanlisib as single agent and in combination with other molecules in cell lines derived from mantle cell lymphoma (MCL), marginal zone lymphoma (MZL) and T cell lymphomas (T-NHLs). Synergism was evaluated with Chou-Talalay combination index, as previously done (Tarantelli et al, CCR 2018). Results: Copanlisib showed an in vitro dose-dependent antitumor activity in the vast majority of the models with a median IC50 of 75 nM (95% C.I., 21-160 nM). The drug was active both in B- (n = 17) and T-NHLs (n = 9), but the latter were less sensitive (285 vs 22 nM, P = 0.0002). The in vitro activity was confirmed using the human JeKo-1 MCL xenograft model. We evaluated 16 combination partners, including rituximab (B-NHL), crizotinib and brentuximab vedotin (T-NHLs), lenalidomide, bendamustine, agents targeting AKT1/2, BCL2, BET, BTK, CDKs (pan, CDK4/6, CDK9), HDAC, JAK1/2, MALT1, and the proteasome. In B-NHLs, copanlisib/venetoclax were the most beneficial (14 synergism, 2 additive), and the 4thbest in T-NHLs (5 synergism, 1 additive). The combination led to increased apoptosis, as shown by a dose-dependent increased PARP cleavage in 3 MZL, and 1 MCL cell lines and by a reduction of cell viability in 2 MCL primary cells. In MZL (SSK41) and MCL (Jeko1) 24h exposure to copanlisib determined a dose-dependent down-regulation of pAKT and anti-apoptotic proteins (BCL-XL in the MZL and of MCL1 in the MCL). These changes were maintained in cells exposed to the combination, but not after venetoclax alone. An in vivo experiment using the SSK41 MZL cell line validated the beneficial effect of this combination and also of copanlisib/lenalidomide (in vitro beneficial in 12/17 B- and 4/9 T-NHL). In T-NHLs, benefit was observed in all ALCL-ALK+ with copanlisib/crizotinib (3/4 synergisms). All but one of the non ALCL-ALK+ cell lines achieved a synergism with copanlisib/ruxolitinib. Copanlisib/brentuximab vedotin was synergistic in the non ALCL-ALK+ and Sezary Syndrome cell lines. Transcriptome analysis identified the PIM1 and PIM2 kinases and the anti-apoptotic gene MCL1 as up-regulated in the MZL cell line HAIR-M exposed to copanlisib (5nM, for 4, 8 and 12h). Thus, we tested combinations with the PIM inhibitor AZD1208 and the MCL1 inhibitor MIK665 (S63845) in 3 MCL and 3 MZL cell lines. Both combinations were synergistic in the HAIR-M and beneficial in additional 5/5 and 3/5 cell lines, respectively. Conclusions: Our study identified a series of active copanlisib-containing combinations and provided the rational for the design of the new SAKK 66/18 phase I study exploring copanlisib plus venetoclax in relapsed/refractory B-cell lymphomas. Keywords: marginal zone lymphoma (MZL); PI3K/AKT/mTOR; venetoclax. Disclosures: Lange, M: Employment Leadership Position: Bayer AG. Jourdan, T: Employment Leadership Position: Bayer AG. Berthold, M: Employment Leadership Position: Bayer AG. Rossi, D: Consultant Advisory Role: Gilead, AbbVie, Janssen, AstraZeneca; Honoraria: Gilead, AbbVie Janssen, Roche; Research Funding: Gilead, AbbVie, Janssen. Stathis, A: Research Funding: Bayer, Merck, Pfizer, Novartis, Roche; Other Remuneration: travel grant from AbbVie. Liu, N: Employment Leadership Position: Bayer AG. Zucca, E: Consultant Advisory Role: Roche, Mei Pharma, Astra Zeneca; Research Funding: Roche, Janssen; Other Remuneration: travel grants from Abbvie and Gilead; expert statements provided to Gilead. Politz, O: Employment Leadership Position: Bayer AG. Bertoni, F: Research Funding: Acerta, Bayer AG; Other Remuneration: travel grants from Astra Zeneca, PIQUR Therapeutics AG.