Poster: ABCL-412 Clinical Activity of CC-99282, a Novel, Oral, Small Molecule Cereblon E3 Ligase Modulator (CELMoD) Agent, in Patients With Relapsed/Refractory Non-Hodgkin Lymphoma (R/R NHL) –Results From CC-99282-NHL-001 (NCT03930953) a First-in-Human, Phase 1, Open-Label, Multicenter Study

CC-99282, a CELMoD® agent, co-opts cereblon to induce targeted degradation of Ikaros/Aiolos. In preclinical studies, CC-99282 exhibited stronger antiproliferative, apoptotic, and immunostimulatory activities compared with lenalidomide and other CELMoD agents. Here we present results of CC-99282 monotherapy in patients with R/R NHL. This 2-part study comprises CC-99282 monotherapy dose escalation (part A) and expansion ± combination partners (part B). Part A includes patients with R/R diffuse large B-cell lymphoma (DLBCL) or follicular lymphoma (FL) that progressed after ≥2 lines of therapy (LOTs) and patients with R/R DLBCL unfit for transplant who have received ≥1 standard LOT. CC-99282 at 0.2, 0.4, 0.6, or 0.8 mg is administered once daily in 3 intermittent, 28-day cycle dosing schedules, with ≥3 patients per cohort. By October 6, 2021, 50 patients received CC-99282 in part A (38 DLBCL, 12 FL; median age 66y; 58% male; 3 median prior LOTs [range 1-8]); 17 remain on treatment, 26 discontinued due to progressive disease. Treatment-related grade 3/4 adverse events were observed in 32 (64%) patients, primarily neutropenia (29 [58%] patients) which was managed with dose modifications and granulocyte colony-stimulating factors. Grade 4 neutropenia during the first month of CC-99282 treatment correlated with prior therapy with ≥4 lines of alkylating agents. All dose-limiting toxicities were hematologic. Maximal recommended doses on the 7/14- and 14/28-days schedules of interest were 0.6 mg and 0.4 mg, respectively. For doses ≥0.4 mg on schedules of interest, responses were durable, and overall response rate was 42% (15/36 evaluable patients; 6 complete and 9 partial responses; 6 FL, 9 DLBCL); responders included patients who progressed on/after cellular therapy and/or immunomodulatory/CELMoD agents. Responses also correlated with early reduction in circulating tumor DNA. CC-99282 was absorbed rapidly with a prolonged median terminal half-life (~50 hours [doses ≥0.4 mg]). Increase in CC-99282 plasma exposure and Ikaros/Aiolos degradation in peripheral T cells were dose-dependent (maximum degradation [>90%] by treatment day 4 [doses ≥0.4 mg]). CC-99282 monotherapy demonstrated a manageable safety profile, with promising efficacy in heavily pretreated patients with R/R NHL. Pharmacokinetic/pharmacodynamic data were consistent with robust/rapid CC-99282-mediated antitumor activity. This BMS-funded study is enrolling patients.