Sven de Vos

BACKGROUND: In patients with chronic lymphoid leukemia (CLL) or small lymphocytic lymphoma (SLL), a short duration of response to therapy or adverse cytogenetic abnormalities are associated with a poor outcome. We evaluated the efficacy of ibrutinib, a covalent inhibitor of Bruton's tyrosine kinase, in patients at risk for a poor outcome. METHODS: In this multicenter, open-label, phase 3 study, we randomly assigned 391 patients with relapsed or refractory CLL or SLL to receive daily ibrutinib or the anti-CD20 antibody ofatumumab. The primary end point was the duration of progression-free survival, with the duration of overall survival and the overall response rate as secondary end points. RESULTS: At a median follow-up of 9.4 months, ibrutinib significantly improved progression-free survival; the median duration was not reached in the ibrutinib group (with a rate of progression-free survival of 88% at 6 months), as compared with a median of 8.1 months in the ofatumumab group (hazard ratio for progression or death in the ibrutinib group, 0.22; P<0.001). Ibrutinib also significantly improved overall survival (hazard ratio for death, 0.43; P=0.005). At 12 months, the overall survival rate was 90% in the ibrutinib group and 81% in the ofatumumab group. The overall response rate was significantly higher in the ibrutinib group than in the ofatumumab group (42.6% vs. 4.1%, P<0.001). An additional 20% of ibrutinib-treated patients had a partial response with lymphocytosis. Similar effects were observed regardless of whether patients had a chromosome 17p13.1 deletion or resistance to purine analogues. The most frequent nonhematologic adverse events were diarrhea, fatigue, pyrexia, and nausea in the ibrutinib group and fatigue, infusion-related reactions, and cough in the ofatumumab group. CONCLUSIONS: Ibrutinib, as compared with ofatumumab, significantly improved progression-free survival, overall survival, and response rate among patients with previously treated CLL or SLL. (Funded by Pharmacyclics and Janssen; RESONATE ClinicalTrials.gov number, NCT01578707.).

PURPOSE: Brentuximab vedotin is an antibody-drug conjugate (ADC) that selectively delivers monomethyl auristatin E, an antimicrotubule agent, into CD30-expressing cells. In phase I studies, brentuximab vedotin demonstrated significant activity with a favorable safety profile in patients with relapsed or refractory CD30-positive lymphomas. PATIENTS AND METHODS: In this multinational, open-label, phase II study, the efficacy and safety of brentuximab vedotin were evaluated in patients with relapsed or refractory Hodgkin's lymphoma (HL) after autologous stem-cell transplantation (auto-SCT). Patients had histologically documented CD30-positive HL by central pathology review. A total of 102 patients were treated with brentuximab vedotin 1.8 mg/kg by intravenous infusion every 3 weeks. In the absence of disease progression or prohibitive toxicity, patients received a maximum of 16 cycles. The primary end point was the overall objective response rate (ORR) determined by an independent radiology review facility. RESULTS: The ORR was 75% with complete remission (CR) in 34% of patients. The median progression-free survival time for all patients was 5.6 months, and the median duration of response for those in CR was 20.5 months. After a median observation time of more than 1.5 years, 31 patients were alive and free of documented progressive disease. The most common treatment-related adverse events were peripheral sensory neuropathy, nausea, fatigue, neutropenia, and diarrhea. CONCLUSION: The ADC brentuximab vedotin was associated with manageable toxicity and induced objective responses in 75% of patients with relapsed or refractory HL after auto-SCT. Durable CRs approaching 2 years were observed, supporting study in earlier lines of therapy.

BACKGROUND: Phosphatidylinositol-3-kinase delta (PI3Kδ) mediates B-cell receptor signaling and microenvironmental support signals that promote the growth and survival of malignant B lymphocytes. In a phase 1 study, idelalisib, an orally active selective PI3Kδ inhibitor, showed antitumor activity in patients with previously treated indolent non-Hodgkin's lymphomas. METHODS: In this single-group, open-label, phase 2 study, 125 patients with indolent non-Hodgkin's lymphomas who had not had a response to rituximab and an alkylating agent or had had a relapse within 6 months after receipt of those therapies were administered idelalisib, 150 mg twice daily, until the disease progressed or the patient withdrew from the study. The primary end point was the overall rate of response; secondary end points included the duration of response, progression-free survival, and safety. RESULTS: The median age of the patients was 64 years (range, 33 to 87); patients had received a median of four prior therapies (range, 2 to 12). Subtypes of indolent non-Hodgkin's lymphoma included follicular lymphoma (72 patients), small lymphocytic lymphoma (28), marginal-zone lymphoma (15), and lymphoplasmacytic lymphoma with or without Waldenström's macroglobulinemia (10). The response rate was 57% (71 of 125 patients), with 6% meeting the criteria for a complete response. The median time to a response was 1.9 months, the median duration of response was 12.5 months, and the median progression-free survival was 11 months. Similar response rates were observed across all subtypes of indolent non-Hodgkin's lymphoma, though the numbers were small for some categories. The most common adverse events of grade 3 or higher were neutropenia (in 27% of the patients), elevations in aminotransferase levels (in 13%), diarrhea (in 13%), and pneumonia (in 7%). CONCLUSIONS: In this single-group study, idelalisib showed antitumor activity with an acceptable safety profile in patients with indolent non-Hodgkin's lymphoma who had received extensive prior treatment. (Funded by Gilead Sciences and others; ClinicalTrials.gov number, NCT01282424.).

Certain malignant B cells rely on B-cell receptor (BCR)-mediated survival signals. Spleen tyrosine kinase (Syk) initiates and amplifies the BCR signal. In in vivo analyses of B-cell lymphoma cell lines and primary tumors, Syk inhibition induces apoptosis. These data prompted a phase 1/2 clinical trial of fostamatinib disodium, the first clinically available oral Syk inhibitor, in patients with recurrent B-cell non-Hodgkin lymphoma (B-NHL). Dose-limiting toxicity in the phase 1 portion was neutropenia, diarrhea, and thrombocytopenia, and 200 mg twice daily was chosen for phase 2 testing. Sixty-eight patients with recurrent B-NHL were then enrolled in 3 cohorts: (1) diffuse large B-cell lymphoma (DLBCL), (2) follicular lymphoma (FL), and (3) other NHL, including mantle cell lymphoma (MCL), marginal zone lymphoma (MZL), mucosa-associated lymphoid tissue lymphoma, lymphoplasmacytic lymphomas, and small lymphocytic leukemia/chronic lymphocytic leukemia (SLL/CLL). Common toxicities included diarrhea, fatigue, cytopenias, hypertension, and nausea. Objective response rates were 22% (5 of 23) for DLBCL, 10% (2 of 21) for FL, 55% (6 of 11) for SLL/CLL, and 11% (1/9) for MCL. Median progression-free survival was 4.2 months. Disrupting BCR-induced signaling by inhibiting Syk represents a novel and active therapeutic approach for NHL and SLL/CLL. This trial was registered at www.clinicaltrials.gov as #NCT00446095.