Cavallo, Federica

PURPOSE Patients with the activated B-cell-like (ABC) subtype of diffuse large B-cell lymphoma (DLBCL) historically showed inferior survival with standard rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). Phase II studies demonstrated that adding the immunomodulatory agent lenalidomide to R-CHOP improved outcomes in ABC-type DLBCL. The goal of the global, phase III ROBUST study was to compare lenalidomide plus R-CHOP (R2-CHOP) with placebo/R-CHOP in previously untreated, ABC-type DLBCL. METHODS Histology and cell-of-origin type were prospectively analyzed by central pathology prior to random assignment and study treatment. Patients with ABC-DLBCL received lenalidomide oral 15 mg/d, days 1-14/21 plus standard R-CHOP21 versus placebo/R-CHOP21 for six cycles. The primary end point was progression-free survival (PFS) per independent central radiology review. RESULTS A total of 570 patients with ABC-DLBCL (n = 285 per arm) were stratified by International Prognostic Index score, age, and bulky disease, and randomly assigned to R2-CHOP or placebo/R-CHOP. Baseline demographics were similar between arms. Most patients completed six cycles of treatment: 74% R2-CHOP and 84% placebo/R-CHOP. The most common grade 3/4 adverse events for R2-CHOP versus placebo/R-CHOP were neutropenia (60% v 48%), anemia (22% v 14%), thrombocytopenia (17% v 11%), and leukopenia (14% v 15%). The primary end point of PFS was not met, with a hazard ratio of 0.85 (95% CI, 0.63 to 1.14) and P = .29; median PFS has not been reached for either arm. PFS trends favoring R2-CHOP over placebo/R-CHOP were seen in patients with higher-risk disease. CONCLUSION ROBUST is the first DLBCL phase III study to integrate biomarker-driven identification of eligible ABC patients. Although the ROBUST trial did not meet the primary end point of PFS in all patients, the safety profile of R2-CHOP was consistent with individual treatments with no new safety signals.

Abstract Background Central nervous system (CNS) relapse of diffuse large B-cell lymphoma (DLBCL) is a devastating event occurring in approximately 5% of patients treated with standard R-CHOP (Thanarajasingam et al, ASH 2015, abs 1456). Isolated CNS relapse is associated with significant morbidity and mortality. New treatment regimens with agents that cross the blood-brain barrier (BBB) are needed. The combination of lenalidomide with R-CHOP (R2CHOP) has shown promising results in activated B-cell (ABC) type DLBCL in phase 2 studies and is currently being evaluated in randomized trials. Lenalidomide crosses the BBB and has been demonstrated to have single-agent activity in relapsed CNS lymphoma. Accordingly, the addition of lenalidomide to R-CHOP may decrease the risk of CNS relapse. Here we characterize the combined incidence of isolated CNS relapse in a population of DLBCL patients who received R2CHOP for induction therapy in two independent phase 2 studies. Methods We analyzed the incidence of isolated CNS relapse in patients with histologically-confirmed DLBCL enrolled in two R2CHOP phase 2 trials - one conducted by Mayo Clinic (MC) and the other by Italian Lymphoma Foundation (FIL) - in the context of clinical variables that included age, gender, disease stage, cell of origin, and administration of CNS prophylaxis. We assessed CNS-International Prognostic Index (CNS-IPI) factors (age, stage, lactate dehydrogenase level, ECOG performance status, extranodal sites, adrenal/kidney involvement) and classified patients into groups of low, intermediate, and high risk of CNS relapse. The risk of CNS relapse in R2CHOP-treated patients was then estimated and compared against published rates in RCHOP-treated patients based on CNS-IPI score. Results One hundred thirty-six patients with DLBCL from both cohorts (87 MC patients, 49 FIL patients) were included in this analysis. Mean age was 65 and median follow-up in 104 patients still alive was 48.2 months (range: 2.1-88.5). 61.8% of patients were male; 86.0% had stage III disease or higher; 44.1% had ECOG performance status of 0; cell of origin phenotype by immunohistochemistry according to Hans algorithm was germinal center B-cell (GCB), non-GCB (ABC), and not available in 43.4%, 36.8%, and 19.8%, respectively; 14.7% received intrathecal (IT) methotrexate for CNS prophylaxis per local practice. No patients received intravenous methotrexate. 10.3%, 71.3%, and 18.4% of patients were classified into low, intermediate, and high-risk CNS-IPI groups, respectively. Only one of 136 patients developed isolated CNS relapse, corresponding to an estimated incidence of CNS relapse of 0.007 (0.7%). Conclusions Despite a large proportion of patients with intermediate and high risk of CNS relapse treated in both phase 2 studies, induction therapy with R2CHOP in patients with DLBCL is associated with a lower-than-expected rate of isolated CNS relapse. The latter is unlikely to be explained by use of IT chemotherapy, which is considered to be marginally effective in this setting and was implemented only in a small proportion of patients. This suggests that addition of CNS-penetrating small molecules, such as lenalidomide, to R-CHOP may decrease the risk of CNS relapse. Disclosures Chiappella: Celgene: Speakers Bureau; Teva: Speakers Bureau; Roche: Speakers Bureau; Pfizer: Speakers Bureau; Janssen-Cilag: Speakers Bureau; Amgen: Speakers Bureau. Nowakowski:Morphosys: Research Funding; Celgene: Research Funding; Bayer: Consultancy, Research Funding. Cavallo:Janssen-Cilag: Honoraria; Onyx: Honoraria; Celgene: Honoraria. Gaidano:Roche: Consultancy, Honoraria, Speakers Bureau; Karyopharm: Consultancy, Honoraria; Morphosys: Consultancy, Honoraria; Gilead: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Novartis: Consultancy, Honoraria, Speakers Bureau. Spina:Mundipharma: Membership on an entity's Board of Directors or advisory committees, Other: Speaker Fee; Teva Pharmaceuticals Industries: Membership on an entity's Board of Directors or advisory committees, Other: Speaker Fee. Vitolo:Takeda: Other: Honoraria for lectures; Gilead: Other: Honoraria for lectures; Janssen: Membership on an entity's Board of Directors or advisory committees, Other: Honoraria for lectures; Roche: Membership on an entity's Board of Directors or advisory committees, Other: Honoraria for lectures.