At the 2012 ASH Annual Meeting, researchers also reported preliminary results for ibrutinib in diffuse large B-cell lymphoma, follicular lymphoma, and multiple myeloma.
A multicenter phase II study in 70 heavily pretreated patients with relapsed or refractory diffuse large B-cell lymphoma in two genetically distinct subtypes—the activated B-cell subtype and the germinal center subtype—found an overall response rate of 23%.1 Responses were primarily in the activated B-cell subtype (41%), including five complete responses and seven partial responses. Investigators suggested that the use of the acivated B-cell molecular subtype could serve as a biomarker for enrichment of patients in future trials.
In relapsed follicular lymphoma, a phase I study in 16 heavily pretreated patients showed the overall response rate to be 44%, including three complete responses.2 In optimally dosed patients, response rates rose to 55% and median progression-free survival was 13.4 months.
In relapsed/refractory multiple myeloma, signals of biologic and clinical activity were observed for ibrutinib.2 Reductions in paraprotein ≥ 50% were seen in three patients, and one patient responded when dexamethasone was added. Decreases in several biomarkers of bone metabolism, angiogenesis, and chemotaxis were associated with treatment. ■
1. Wilson WH, Gerecitano J, Goy A, et al: The Bruton’s tyrosine kinase inhibitor, ibrutinib (PCI-32765), has preferential activity in the ABC subtype of relapsed/refractory de novo diffuse large B-cell lymphoma: Interim results of a multicenter, open-label, phase 2 study. 2012 ASH Annual Meeting. Abstract 686. Presented December 10, 2012.
2. Fowler N, Advani R, Sharman J, et al: The Bruton’s tyrosine kinase inhibitor ibrutinib (PCI-32765) is active and tolerated in relapsed follicular lymphoma. 2012 ASH Annual Meeting. Abstract 156. Presented December 9, 2012.