CLL2-BIG: sequential treatment with bendamustine, ibrutinib and obinutuzumab (GA101) in chronic lymphocytic leukemia

Obinutuzumab (GA101) and ibrutinib show excellent efficacy for treatment of chronic lymphocytic leukemia (CLL). Preclinical investigations and a complementary safety profile were in support of testing their combined use. The exploratory CLL2-BIG-trial evaluated a sequential combination therapy following a recently proposed strategy. Two courses of bendamustine were used for debulking in patients with a high tumor load, followed by six courses of induction therapy with ibrutinib and GA101, followed by an MRD-triggered maintenance phase. The results of a pre-planned analysis at the end of the induction phase are presented. 61 patients were included, 30 previously untreated and 31 with relapsed/refractory CLL. 44 patients received bendamustine. During induction, neutropenia (14.8%) and thrombocytopenia (13.1%) were the most common CTC grade 3 and 4 events. One fatality (duodenitis) occurred. The overall response rate was 100%. 54.1% of patients achieved a partial remission, 41% a clinical complete remission (cCR) without confirmation by CT scan or bone marrow (BM) biopsy according to protocol and 4.9% a cCR with incomplete recovery of the BM. 29 patients (47.5%) had no detectable (<10^-4) minimal residual disease assessed by flow cytometry in peripheral blood. In conclusion, the BIG regimen is a safe and highly effective therapy for CLL.