Abstract CT174: A phase 1 study of JBH492, an anti C-C chemokine receptor 7 antibody-drug conjugate (anti-CCR7 ADC), assessing safety and efficacy in lymphoid malignancies

Abstract Background: CCR7 is overexpressed in lymphoid malignancies. JBH492 is a first-in-class CCR7-targeting ADC, comprising a humanized, Fc-silenced anti-CCR7 IgG1 antibody conjugated to maytansinoid microtubule inhibitor DM4 via a cleavable linker. Preclinical studies support avidity-driven differential binding in CCR7-high tumor cells compared to CCR7-low healthy immune cells, and in vivo animal studies demonstrated robust and durable efficacy in multiple clinically relevant lymphoma models (Dang et al. 2022). Methods: This is an ongoing first-in-human, open-label, phase I/Ib, multi-center study in patients (pts) with relapsed/refractory (r/r) chronic lymphocytic leukemia (CLL) and non-Hodgkin’s lymphoma (NHL) (NCT04240704), which completed enrollment for dose-escalation phase. Five dose levels of JBH492 monotherapy ranging from 0.4 to 3.6 mg/kg (intravenous administration every 3 weeks [q3W]) were tested with 3 - 7 pts enrolled per dose level. Preclinical data from xenografts predicted tumor stasis at 1.6 mg/kg q3W. The objective of dose escalation was to assess safety, tolerability, pharmacokinetics (PK), immunogenicity, and preliminary efficacy of JBH492 and to determine maximum tolerated and recommended doses. Pts with r/r CLL and NHL, who failed standard of care therapy (at least 2 prior regimens) and who were intolerant/ineligible to approved therapies, were included; CCR7 expression confirmation was not required prior enrollment. Results: Total 25 pts with r/r stage II-IV NHL (n = 24, [adult T cell leukemia-lymphoma, 3; cutaneous T cell lymphoma, 4; diffuse large B cell lymphoma, 7; follicular lymphoma, 1; Mantle cell lymphoma, 1; marginal zone lymphoma, 2; peripheral T cell lymphoma, 3; others, 3]) and CLL (n = 1) with median age 69.0 y (43 - 85) were enrolled. Mean duration of exposure was 13.5 wks. One pt had dose-limiting toxicity — grade (G) 3 thrombocytopenia lasting for 13 d. Overall, 23 (92%) pts had at least 1 adverse event (AE) (G ≥ 3, n = 11). Treatment-related AEs (TRAEs) were reported in 15 (60%) pts (G ≥ 3, n = 3). Of 6 (24%) pts who had serious AEs (SAEs) (G ≥ 3, n = 3), 2 (8%) had TRSAE. The most frequent AEs (≥ 20%) included anemia (32%), thrombocytopenia (28%), neutropenia and dry eye (20% each). Two deaths due to underlying disease were reported. PK for total ADC was roughly dose proportional. Four NHL pts (2 T-NHL and 2 B-NHL) had partial response (PR) and 2 had stable disease, with PRs observed at doses between 2.4 and 3.6 mg/kg q3W. Post data-cut-off, 1 pt with T-NHL achieved CR following 4 cycles of treatment. No correlation between CCR7 expression and response could be drawn (CCR7 expression was observed in all samples from 14 pts). Conclusions: The data from this phase I study suggest that targeting CCR7 with JBH492 is a promising therapeutic strategy for lymphoid malignancies with manageable hematological and non-hematological safety profile. [K.I. and S.L. contributed equally to this study.] Citation Format: Pau Abrisqueta, Reinhard Marks, Irit Avivi, Martin Wermke, Francesca Lim, Tae Min Kim, Alba Cabirta Touzon, Kristiina Karihtala, Shinichi Makita, Lillian Werner, Chiaki Tanaka, Anhthu Dang, Anwesha Chaudhury, Seth Rice, Rowshan Chowdhury, Deborah Knee, Belén Gomezcarrillo, Elissa Furutani, Koji Izutsu, Sirpa Leppä. A phase 1 study of JBH492, an anti C-C chemokine receptor 7 antibody-drug conjugate (anti-CCR7 ADC), assessing safety and efficacy in lymphoid malignancies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT174.