Leonard M. Klein

An open-label phase 2 trial of entospletinib (GS-9973), a selective spleen tyrosine kinase inhibitor, in chronic lymphocytic leukemia

Small-molecule inhibitors of kinases involved in B-cell receptor signaling are an important advance in managing lymphoid malignancies. Entospletinib (GS-9973) is an oral, selective inhibitor of spleen tyrosine kinase. This multicenter, phase 2 study enrolled subjects with relapsed or refractory chronic lymphocytic leukemia (CLL; n = 41) or non-Hodgkin lymphoma (n = 145). Participants received 800 mg entospletinib twice daily. We report efficacy outcomes in the CLL cohort (n = 41) and safety outcomes in all cohorts (N = 186). The primary end point was a progression-free survival (PFS) rate at 24 weeks in subjects with CLL. The PFS rate at 24 weeks was 70.1% (95% confidence interval [CI], 51.3%-82.7%); median PFS was 13.8 months (95% CI, 7.7 months to not reached). The objective response rate was 61.0% (95% CI, 44.5%-75.8%), including 3 subjects (7.3%) who achieved nodal response with persistent lymphocytosis. Fifty-four subjects (29.0%) had serious adverse events (SAEs). The most common treatment-emergent SAEs included dyspnea, pneumonia, febrile neutropenia, dehydration, and pyrexia. Common grade 3/4 laboratory abnormalities included neutropenia (14.5%) and reversible alanine aminotransferase/aspartate aminotransferase elevations (13.4%). Entospletinib demonstrates clinical activity in subjects with relapsed or refractory CLL with acceptable toxicity. This trial was registered at www.clinicaltrials.gov as #NCT01799889.

Ublituximab (TG-1101), a novel glycoengineered anti-CD20 antibody, in combination with ibrutinib is safe and highly active in patients with relapsed and/or refractory chronic lymphocytic leukaemia: results of a phase 2 trial.

Ibrutinib is effective in patients with chronic lymphocytic leukaemia (CLL); however, treatment resistance remains a problem. Ublituximab is a novel, glycoengineered anti‐CD20 monoclonal antibody with single‐agent activity in relapsed CLL. We report the results of a phase 2 study evaluating combination therapy with ibrutinib and ublituximab in patients with relapsed or refractory CLL. Patients received ibrutinib 420 mg once daily. Ublituximab was administered on days 1, 8 and 15 of cycle 1 followed by day 1 of cycles 2–6. Response assessments were completed at cycles 3 and 6; patients then continued on ibrutinib monotherapy per standard of care. Forty‐one of 45 enrolled patients were evaluable for efficacy. Safety was consistent with prior experience for each drug, with infusion reactions the most prevalent adverse event. Combination therapy resulted in an overall response rate (ORR) of 88% at 6 months. In the 20 patients with high‐risk features (17p or 11q deletions or TP53 mutation) and evaluable for efficacy, the ORR was 95%, with three patients (15%) achieving negative minimal residual disease. Median time to response was 8 weeks. Ublituximab in combination with ibrutinib resulted in rapid and high response rates. The long‐term clinical benefit of ublituximab will be defined by an ongoing phase 3 trial (NCT 02301156).

Safety and efficacy of pomalidomide, dexamethasone and pegylated liposomal doxorubicin for patients with relapsed or refractory multiple myeloma

Immunomodulatory drugs including thalidomide, lenalidomide (LEN) and pomalidomide (POM), are effective for treating multiple myeloma (MM). POM has shown enhanced efficacy with dexamethasone (DEX). Pegylated liposomal doxorubicin (PLD) with bortezomib is US Food and Drug Administration‐approved for treating MM. PLD with LEN or thalidomide has shown efficacy for MM patients. LEN with DEX, PLD and bortezomib achieves high response rates. We evaluated the combination of POM with DEX 40 mg and PLD 5 mg/m2 with the latter two drugs administered on days 1, 4, 8 and 11 on a 28‐day cycle for the treatment of relapsed/refractory MM patients. During Phase 1, the maximum tolerated dose of POM was 4 mg, and was used in Phase 2, which also required patients to be refractory to LEN. However, neutropenia ≥ grade 3 was observed in 10/17 (59%) patients, and the dose was lowered to 3 mg. Median PFS was 5·4 months (range, 0·3–29·0 + months). Overall response rates for patients in Phase 2 were 39% and 31% among subjects receiving POM at 3 mg and 4 mg, respectively, and clinical benefit rates were 51% and 44%, respectively. POM, PLD and DEX is a treatment option for relapsed/refractory MM patients including those who are refractory to LEN.

An open-label phase 2 trial of entospletinib in indolent non-Hodgkin lymphoma and mantle cell lymphoma

Spleen tyrosine kinase (Syk) mediates B‐cell receptor signalling in normal and malignant B cells. Entospletinib is an oral, selective Syk inhibitor. Entospletinib monotherapy was evaluated in a multicentre, phase 2 study of patients with relapsed or refractory indolent non‐Hodgkin lymphoma or mantle cell lymphoma (MCL). Subjects received 800 mg entospletinib twice daily. Forty‐one follicular lymphoma (FL), 17 lymphoplasmacytoid lymphoma/Waldenström macroglobulinaemia (LPL/WM), 17 marginal zone lymphoma (MZL) and 39 MCL patients were evaluated. The primary endpoint was a progression‐free survival (PFS) rate (defined as not experiencing progression or death) at 16 weeks for patients with MCL and at 24 weeks for patients with FL, LPL/WM and MZL. The most common treatment‐emergent adverse events were fatigue, nausea, diarrhoea, vomiting, headache and cough. Common laboratory abnormalities were anaemia, neutropenia and thrombocytopenia; aspartate transaminase, alanine transaminase, total bilirubin and serum creatinine were all increased. PFS at 16 weeks in the MCL cohort was 63·9% [95% confidence interval (CI) 45–77·8%]; PFS at 24 weeks in the FL, LPL/WM, MCL and MZL cohorts was 51·5% (95% CI 32·8–67·4%), 69·8% (95% CI 31·8–89·4%), 56·6% (95% CI 37·5–71·8%) and 46·2% (95% CI 18·5–70·2%), respectively. Entospletinib had limited single‐agent activity with manageable toxicity in these patient populations.