Prognostic and Immune-Related Factors for Response to Duvelisib in the Phase 2 DYNAMOTM Clinical Trial in iNHL

Introduction: Indolent NHL (iNHL) remains largely incurable, with the majority of patients (pts) eventually becoming refractory to standard therapies, necessitating new effective and tolerable treatments. Duvelisib is an oral dual PI3K-δ,γ inhibitor being developed for the treatment of hematologic malignancies, including CLL/SLL and follicular lymphoma (FL). In the Phase 2 DYNAMO trial of duvelisib monotherapy for relapsed/refractory iNHL(NCT01882803), the FL subgroup (n=83) had a median progression-free survival (mPFS) of 8.3 months (mo) and an overall response rate (ORR) of 43%. Although adverse events (AEs) observed with other PI3K-inhibitors also occurred with duvelisib, they infrequently led to discontinuation of treatment. An understanding of prognostic factors that can inform duvelisib responsiveness would be valuable for guiding patient selection treatment options. This study presents updated data on prognostic factors potentially associated with duvelisib efficacy and safety. Methods: To identify FL risk subgroups, clinical parameters were assessed according to the FL Prognostic Index (FLIPI). Incidences of AEs (per combined preferred term: neutropenia, diarrhea, colitis, pneumonia, pneumonitis, transaminase elevation, rash, and infections) were also evaluated for associations with clinical responses. Blood collected at baseline (Cycle1 Day1) was analyzed by a central laboratory for a 7 gene expression signature to generate the combined M7-FLIPI, and biopsies were evaluated at screening for del(6q) cytogenetics. In addition, baseline immune cell counts (subgrouped low [L] or high [H] by flow cytometry), and levels of key chemokines, cytokines, and serum factors were centrally assessed. Multivariate regression models were developed via a stepwise procedure from a selection of these parameters identified by individual univariate analysis for the efficacy endpoints of mPFS and ORR. Results: In the DYNAMO study, there were no significant differences in mPFS, ORR, or lymph node response rate (LNRR) identified for FL pts between high and low risk subgroups stratified by prognostic indexes. Efficacy responses were similar using the FLIPI (FLIPI Prognostic factors selected via univariate analyses for mPFS or ORR were advanced into multivariate models. None of these factors reached significance in a multivariate mPFS model, and only CD3H was significant in a stepwise ORR model (odds ratio H/L=2.69, 95% CI [1.20,6.06]). The FL pt subgroups having AEs were evaluated for mPFS (mo [95% CI] as follows: neutropenia, 8.3 mo [3.5,11.8], n=25; diarrhea 11.0 mo [8.3,16.4], n=40; colitis 10.0 mo [8.3,24.0], n=5; rash 8.3 mo [1.9,28.0], n=26; transaminase elevation, 11.8 mo [1.4,24.0], n=12; pneumonitis 13.0 mo [9.5,16.4], n=4; pneumonia 12.0 [4.2,28.0], n=8; and infection 9.0 [3.7,12.0], n=38. Conclusion In the Phase 2 DYNAMO study, mPFS and ORR were similar for duvelisib-treated FL pts regardless of poor prognostic indicators, including FLIPI, M7-FLIPI, and chromosome 6q deletions. Elevated levels of CXCL11 and IL2RA correlated with shorter mPFS. This analysis also shows that AEs, when managed, allow continued treatment with duvelisib and increased benefit as demonstrated by mPFS. Overall, these data suggest that duvelisib as a single-agent is effective in FL patients, including pts with poor prognostic factors. Disclosures Zinzani: SERVIER: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Merck: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Gilead: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celltrion: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Merck: Honoraria, Membership on an entity's Board of Directors or advisory committees; TG Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Speakers Bureau; Takeda: Membership on an entity's Board of Directors or advisory committees; Bayer: Membership on an entity's Board of Directors or advisory committees; MSD: Honoraria, Speakers Bureau; PFIZER: Honoraria, Membership on an entity's Board of Directors or advisory committees; PFIZER: Honoraria, Membership on an entity's Board of Directors or advisory committees; TG Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees; Verastem: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Astra Zeneca: Speakers Bureau; BMS: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Flinn:Novartis: Research Funding; Infinity: Research Funding; Takeda: Research Funding; Gilead: Research Funding; Trillium: Research Funding; Constellation: Research Funding; Curis: Research Funding; Verastem: Research Funding; TG Therapeutics: Research Funding; Verastem: Consultancy, Research Funding; BeiGene: Research Funding; Calithera: Research Funding; Constellation: Research Funding; Celgene: Research Funding; Seattle Genetics: Research Funding; Forty Seven: Research Funding; Merck: Research Funding; Gilead: Research Funding; Takeda: Research Funding; Pharmacyclics: Research Funding; Verastem: Research Funding; Trillium: Research Funding; Portola: Research Funding; TG Therapeutics: Research Funding; Forma: Research Funding; Forma: Research Funding; Genentech: Research Funding; ArQule: Research Funding; Genentech: Research Funding; Incyte: Research Funding; Agios: Research Funding; ArQule: Research Funding; Pfizer: Research Funding; Portola: Research Funding; Novartis: Research Funding; BeiGene: Research Funding; Celgene: Research Funding; Kite: Research Funding; Kite: Research Funding; Merck: Research Funding; Forty Seven: Research Funding; Pfizer: Research Funding; Agios: Research Funding; Seattle Genetics: Research Funding; Verastem: Consultancy, Research Funding; Calithera: Research Funding; Infinity: Research Funding; Janssen: Research Funding; Curis: Research Funding; Incyte: Research Funding; Janssen: Research Funding; Pharmacyclics: Research Funding. Miller:CTI: Research Funding; Gilead: Honoraria, Research Funding; Incyte: Consultancy, Honoraria, Research Funding, Speakers Bureau; Novartis: Honoraria, Speakers Bureau. Ardeshna:Celgene: Membership on an entity's Board of Directors or advisory committees; ADC Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Conference expenses, Research Funding. Le:Verastem Oncology: Employment. Pachter:Verastem Inc: Employment, Other: Stockholder. Sprott:Verastem Oncology: Employment. Lustgarten:Verastem Oncology: Employment. Weaver:Verastem Oncology: Employment, Other: Stockholder; Agios Pharmaceuticals: Employment; Femto Dx: Equity Ownership. Wagner-Johnston:Novartis: Research Funding; ASTEX: Research Funding; Celgene: Research Funding; JUNO: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Merck: Research Funding; ADC Therapeutics: Honoraria, Membership on an entity's Board of Directors or advisory committees.