Advanced B-cell non-Hodgkin Lymphoma Research Articles

Abstract PO-010: Trial in Progress: Phase 1 Study of ARV-393, a PROTAC BCL6 Degrader, in Advanced Non-Hodgkin Lymphoma

Abstract Background: Non-Hodgkin lymphoma (NHL) represents a biologically and clinically diverse group of hematologic malignancies originating from B cells, T cells, and/or natural killer cells, with those of B-cell origin constituting ∼80–85% of all NHL cases. The BCL6 transcription factor is a key oncogenic driver of B-cell lymphomagenesis, and deregulated BCL6 expression is a common feature of diffuse large B-cell lymphoma (DLBCL), the most common type of NHL. BCL6 translocations have been observed in follicular lymphomas, the second most prevalent NHL, with studies suggesting that these translocations may portend a higher risk of transformation into aggressive lymphoma. BCL6 is also a lineage-defining transcription factor of T follicular helper cells, the cell of origin for angioimmunoblastic T-cell lymphoma (AITL). Moreover, BCL6 expression has been identified in biopsies of patients with AITL, and its continued expression was required for tumor growth in a mouse model of AITL, supporting BCL6 as a cancer driver in this type of NHL as well. ARV-393, an orally administered PROteolysis TArgeting Chimera (PROTAC) BCL6 degrader, is a bifunctional small molecule consisting of a BCL6-binding domain attached by a linker to a cereblon E3 ubiquitin ligase–binding domain. ARV-393 induces ubiquitination and subsequent degradation of BCL6 by the proteasome. In preclinical studies, ARV-393 induced rapid and robust degradation (>90%) of BCL6 in NHL cell lines and demonstrated dose-responsive tumor growth inhibition leading to tumor stasis or regression in xenograft models, supporting further investigation in patients with NHL. This multicenter, first-in-human, phase 1 study will evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics, and preliminary antitumor activity of ARV-393 in patients with advanced B-cell NHL or AITL. Methods: Eligible patients (aged ≥18 years) have relapsed/refractory mature B-cell NHL and ≥2 prior systemic therapies, or histologically confirmed AITL that has recurred or progressed following institutional standard-of-care therapy. Patients must also have ≥1 measurable lesion at study entry, Eastern Cooperative Oncology Group performance status of 0 or 1, freshly biopsied or archival tumor tissue available, adequate organ function, no active central nervous system involvement, and no prior allogeneic stem cell transplant or solid organ transplantation. Autologous stem cell transplant must not have occurred ≤100 days and previous CAR T-cell therapy ≤60 days prior to cycle 1 day 1 of ARV-393 treatment. ARV-393 will be administered orally in 28-day cycles with dose escalation according to a Bayesian optimal interval design. The primary objectives are to evaluate the safety and tolerability of ARV-393, determine maximum tolerated dose if necessary, and identify the recommended phase 2 dose(s) and dosing schedule. Secondary objectives are to characterize the pharmacokinetic profile of ARV-393 and evaluate its preliminary anti-tumor activity. Enrollment for this study will open in 2024. Citation Format: Paolo Caimi, Scott Huntington, Sean Landrette, Sheryl M Gough, Vivian Dai, Bryan Jackson, Juan Chavez, Sarah Tannenbaum-Dvir, Matthew Matasar. Trial in Progress: Phase 1 Study of ARV-393, a PROTAC BCL6 Degrader, in Advanced Non-Hodgkin Lymphoma [abstract]. In: Proceedings of the Fourth AACR International Meeting on Advances in Malignant Lymphoma: Maximizing the Basic-Translational Interface for Clinical Application; 2024 Jun 19-22; Philadelphia, PA. Philadelphia (PA): AACR; Blood Cancer Discov 2024;5(3_Suppl):Abstract nr PO-010.

Abstract CT146: AZD0466 in patients with advanced non-Hodgkin lymphoma: Efficacy and safety in an open-label phase 1 trial

Abstract Background Overexpression of pro-survival proteins Bcl-2 and Bcl-xL have been associated with poor prognosis in patients with non-Hodgkin lymphoma (NHL). AZD0466 is a drug-dendrimer conjugate consisting of the dual Bcl-2/Bcl-xL inhibitor AZD4320 covalently conjugated to a pegylated poly-L-lysine dendrimer, which allows for gradual release by hydrolysis. Preclinically, AZD0466 monotherapy has demonstrated efficacy in xenograft models of diffuse large B-cell lymphoma (DLBCL). Here, we report results from a Phase 1 trial (NCT05205161) of AZD0466 in relapsed/refractory (R/R) advanced B-cell NHL (B-NHL). Methods Eligible patients were ≥18 years old and had received 2-5 prior lines of therapy. AZD0466 was administered intravenously, with a dose ramp-up on days 1 and 4 of a 28-day cycle, and weekly administration of the target dose from day 8. The primary objective of the dose escalation phase was to assess the safety and tolerability of AZD0466 in patients with R/R B-NHL and to identify the maximum tolerated dose and recommended phase 2 dose. Preliminary efficacy was evaluated using Lugano 2014 criteria. Secondary objective was evaluation of pharmacokinetic (PK) parameters for the study drug. Results As of November 02, 2023, 7 patients (DLBCL n=5, follicular lymphoma n=1, marginal zone lymphoma (MZL) n=1; median age, 57 [26−79] years) had received AZD0466 at 600 mg (n=3), 1200 mg (n=3), or 2400 mg (n=1). All patients experienced adverse events (AEs). AEs possibly related to AZD0466 were reported in 6 patients, most common: platelet count decrease (57.1%), neutropenia/neutrophil count decrease (42.9%), and hypophosphatemia (28.6%). Grade ≥3 AEs possibly related to AZD0466 were reported in 4 patients: 2 Grade 3 and 1 Grade 4 neutropenia/neutrophil count decrease, and 2 AEs that led to treatment discontinuation (Grade 3 platelet count decrease and dose-limiting Grade 3 troponin increase). Among 6 evaluable patients across all dose levels, 1 patient with MZL treated at 1200 mg had an objective response (partial response). Another 3 patients had a best overall response of stable disease and 2 patients had progressive disease. One patient discontinued the study prior to disease assessment. AZD4320 exposure was dose-proportional, with PK profiles similar to studies with other hematologic malignancies. As a surrogate of Bcl-xL on-target activity, transient thrombocytopenia with moderate platelet count recovery prior to the next dose was observed in most patients, in line with preclinical modeling. Pharmacodynamic modulation based on cleaved caspase-3 induction by AZD0466 was observed at 1200 and 2400 mg. Conclusion AZD0466 ≤1200 mg was clinically well tolerated but evidence of asymptomatic myocardial injury was observed at 2400 mg. The study was terminated due to similar findings in a concurrent trial (D8241C00001; NIMBLE). With an objective response observed at the 1200 mg dose level, further development of agents targeting Bcl-2/xL in NHL is warranted with efforts to reduce the cardiotoxicity profile. Citation Format: Geoffrey Chong, Franck Morschhauser, Alex Herrera, Ki-Seong Eom, Tae Min Kim, Michael Wang, Connor Hall, Fathima Zumla Cader, Kaitlyn Beyfuss, Patricia Cheung, Wei Quan, Shringi Sharma, Yotvat Marmor, Jamal Saeh, Jose Mariz. AZD0466 in patients with advanced non-Hodgkin lymphoma: Efficacy and safety in an open-label phase 1 trial [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 CT146.

Safety and efficacy of a novel anti-CD19 chimeric antigen receptor T cell product targeting a membrane-proximal domain of CD19 with fast on- and off-rates against non-Hodgkin lymphoma: a first-in-human study

BackgroundCommercial anti-CD19 chimeric antigen receptor T-cell therapies (CART19) are efficacious against advanced B-cell non-Hodgkin lymphoma (NHL); however, most patients ultimately relapse. Several mechanisms contribute to this failure, including CD19-negative escape and CAR T dysfunction. All four commercial CART19 products utilize the FMC63 single-chain variable fragment (scFv) specific to a CD19 membrane-distal epitope and characterized by slow association (on) and dissociation (off) rates. We hypothesized that a novel anti-CD19 scFv that engages an alternative CD19 membrane-proximal epitope independent of FMC63 and that is characterized by faster on- and off-rates could mitigate CART19 failure and improve clinical efficacy.MethodsWe developed an autologous CART19 product with 4-1BB co-stimulation using a novel humanized chicken antibody (h1218). This antibody is specific to a membrane-proximal CD19 epitope and harbors faster on/off rates compared to FMC63. We tested h1218-CART19 in vitro and in vivo using FMC63-CART19-resistant models. We conducted a first-in-human multi-center phase I clinical trial to test AT101 (clinical-grade h1218-CART19) in patients with relapsed or refractory (r/r) NHL.ResultsPreclinically, h1218- but not FMC63-CART19 were able to effectively eradicate lymphomas expressing CD19 point mutations (L174V and R163L) or co-expressing FMC63-CAR19 as found in patients relapsing after FMC63-CART19. Furthermore, h1218-CART19 exhibited enhanced killing of B-cell malignancies in vitro and in vivo compared with FMC63-CART19. Mechanistically, we found that h1218-CART19 had reduced activation-induced cell death (AICD) and enhanced expansion compared to FMC63-CART19 owing to faster on- and off-rates. Based on these preclinical results, we performed a phase I dose-escalation trial, testing three dose levels (DL) of AT101 (the GMP version of h1218) using a 3 + 3 design. In 12 treated patients (7 DLBCL, 3 FL, 1 MCL, and 1 MZL), AT101 showed a promising safety profile with 8.3% grade 3 CRS (n = 1) and 8.3% grade 4 ICANS (n = 1). In the whole cohort, the overall response rate was 91.7%, with a complete response rate of 75.0%, which improved to 100% in DL-2 and -3. AT101 expansion correlates with CR and B-cell aplasia.ConclusionsWe developed a novel, safe, and potent CART19 product that recognizes a membrane-proximal domain of CD19 with fast on- and off-rates and showed significant efficacy and promising safety in patients with relapsed B-cell NHL.Trial registrationNCT05338931; Date: 2022–04-01.