ABT-199: Interim Phase Ib data

Interim data from 18 evaluable patients who completed combination therapy or discontinued treatment prior to completion in an open-label, U.S. and Australian Phase Ib trial showed that once-daily ABT-199 plus Rituxan rituximab led to 7 complete remissions (CRs) or CRs with incomplete hematologic recovery (CRi) and 7 partial remissions (PRs). In 19 patients yet to complete combination therapy, ABT-199 plus Rituxan led to 4 confirmed PRs and 9 unconfirmed PRs, with 6 patients not yet evaluable. The initial starting dose of ABT-199 was 50 mg, but was reduced to 20 mg due to a fatal case of tumor lysis syndrome. The most common grade 3/4 adverse events were neutropenia, thrombocytopenia and anemia. There were 2 dose-limiting toxicities (DLTs), 1 case each of thrombocytopenia and hemophagocytic syndrome at the 300 mg dose of ABT-199. Data were presented at the American Society of Clinical Oncology meeting in Chicago. ...