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Combination of ibrutinib with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) for treatment-naive patients with CD20-positive B-cell non-Hodgkin lymphoma: a non-randomised, phase 1b study
Anas Younes, Catherine Thieblemont, Franck Morschhauser, Ian Flinn, Jonathan W Friedberg, Sandy Amorim, Benedicte Hivert, Jason Westin, Jessica Vermeulen, Nibedita Bandyopadhyay, Ronald de Vries, Sriram Balasubramanian, Peter Hellemans, Johan W Smit
Original Research Article
The Lancet Oncology, Volume 15, Issue 9, August 2014, Pages 1019-1026
Targeting the B-cell receptor signaling represents one of the most promising approach for B-cell derived lymphoid neoplasms. The data so far published with the PI3K-delta inhibitor idelalisib and with the BTK-inhibitor ibrutinib as single agents are interesting although it is logic to combine them with conventional or other targeted compounds. Here, Younes and Coll. presents the phase 1 study of ibrutinib combined with the standard regimen R-CHOP in patients with untreated CD20+ B cell lymphomas. The regimen was well tolerated and active. Importantly, there were more responses in activated B cell-like A(BC) diffuse large B cell (DLBCL) lymphomas than among the germinal center B cell (GCB) type DLBCL, in accordance with the previous pre-clinical and clinical reports.
Present first-line therapy for diffuse large B-cell lymphoma, a subtype of non-Hodgkin lymphoma, is rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP). Ibrutinib, a novel oral Bruton's tyrosine kinase inhibitor, has shown single-drug activity in relapsed or refractory B-cell malignancies. We investigated the safety and efficacy of ibrutinib in combination with R-CHOP for patients with previously untreated CD20-positive B-cell non-Hodgkin lymphoma.
In this phase 1b, open-label, non-randomised study, patients were recruited across six centres in the USA and France. Eligibility was age 18 years or older and treatment-naive histopathologically confirmed CD20-positive B-cell non-Hodgkin lymphoma. In the dose-escalation phase (part 1), patients with diffuse large B-cell lymphoma, mantle-cell lymphoma, or follicular lymphoma were enrolled. The primary objective was to determine a recommended phase 2 dose of ibrutinib with a standard R-CHOP regimen, by assessing safety in all patients who received treatment. Patients received ibrutinib 280 mg, 420 mg, or 560 mg per day in combination with a standard R-CHOP regimen every 21 days. Safety of the recommended phase 2 dose was then assessed in a dose-expansion population, which consisted of patients with newly diagnosed diffuse large B-cell lymphoma (part 2). Secondary objectives included assessments of the proportion of patients who had an overall response, pharmacokinetics, and pharmacodynamics. This trial is registered with ClinicalTrials.gov, number NCT01569750.
From June 22, 2012, to March 25, 2013, 33 patients were enrolled (part 1: 17; part 2: 16) and 32 received ibrutinib plus R-CHOP treatment (one patient in the part 2 cohort withdrew). The maximum tolerated dose was not reached and the recommended phase 2 dose for ibrutinib was 560 mg per day. The most common grade 3 or greater adverse events included neutropenia (73% [24 of 33 patients]), thrombocytopenia (21% [seven patients]), and febrile neutropenia and anaemia (18% each [six patients]). The most frequently reported serious adverse events were febrile neutropenia (18% [six patients]) and hypotension (6% [two patients]). 30 (94%) of 32 patients who received one or more doses of combination treatment achieved an overall response. All 18 patients with diffuse large B-cell lymphoma who received the recommended phase 2 dose had an overall response. For those subtyped and treated at the recommended phase 2 dose, five (71%) of seven patients with the germinal centre B-cell-like subtype and two (100%) patients with the non-germinal centre B-cell-like subtype had a complete response. R-CHOP did not affect pharmacokinetics of ibrutinib, and ibrutinib did not alter the pharmacokinetics of vincristine. Pharmacodynamic data showed Bruton's tyrosine kinase was fully occupied (>90% occupancy) at the recommended phase 2 dose.
Ibrutinib is well tolerated when added to R-CHOP, and could improve responses in patients with B-cell non-Hodgkin lymphoma, but our findings need confirmation in a phase 3 trial.