Long-Term Results of Ibrutinib/Umbralisib Show Efficacy in CLL and MCL

This article was originally published by Targeted Oncology

Matthew S. Davids, MD, associate director of the Center for Chronic Lymphocytic Leukemia, director, Clinical Research for the Lymphoma Program at the Dana-Farber Cancer Institute, and associate professor of Medicine at Harvard Medical School, discusses the long-term follow-up of a phase 1/1b trial (NCT02268851) for patients with relapsed/refractory chronic lymphocytic leukemia (CLL) or mantle cell lymphoma (MCL) receiving ibrutinib (Imbruvica) and umbralisib.

The initial results were presented early in 2019 with about 2 years of follow-up, showing high rates of response in patients with CLL and MCL, according to Davids. There was good tolerability observed for these patients, and the investigators were able to identify the recommended phase 2 dose for umbralisib of 800 mg combined with the standard dose of ibrutinib.

The challenge with the initial report was that the follow-up for these patients was short, Davids says. The goal of the update at the 2020 European Hematology Association Congress was to present about 4 years of follow-up of the progression-free survival (PFS) and overall survival (OS) of the high-risk patients. The investigators also looked at the rates of complete remission, which increased over time.

For patients with MCL, the median PFS was around 11 months, and the median OS was about 2 and a half years. Davids thinks that this didn’t look much different than ibrutinib monotherapy, and it is hard to tell if there is a difference between monotherapy and this combination.

Davids says the investigators saw the bigger difference in the patients with CLL compared to historical control studies. There was about an 80% 4-year PFS in the high-risk CLL population and a 4-year OS of 90%. There are still many patients on the ibrutinib and umbralisib combination. The data set highlights the efficacy and safety of dual B-cell receptor blockade and warrants further study, he believes.