Paolo Ghia, MD, PhD, Professor at the Università Vita-Salute San Raffaele, Milan, Italy, and Director of the Strategic Research Program on CLL, discusses the difference between disease-free survival (DFS) and progression-free survival (PFS) within the context of the phase 2 CAPTIVATE study. The CAPTIVATE study evaluated ibrutinib plus venetoclax as a first-line treatment for chronic lymphocytic leukemia (CLL); data from this trial was recently presented at the American Society of Hematology Meeting & Exposition (ASH 2021)

CLL is a rare blood cancer resulting in a build-up of lymphocytes in bone marrow, lymph nodes, and blood. The disease is treatable, but relapse is very common.

The CAPTIVATE study is a multicenter, double-blind, phase 2 study with previously untreated CLL patients under the age of 70 years. Patients were given 3 cycles of ibrutinib and an additional 12 cycles of ibrutinib plus venetoclax. Patients who had confirmed rates of undetectable minimal residual disease (uMRD) were then randomized to receive ibrutinib or placebo. Patients who did not meet the definition of undetectable MRD were randomized to receive ibrutinib alone or continued combination therapy. One of the study’s endpoints was 2-year DFS rate in patients with confirmed uMRD randomized to placebo vs ibrutinib.

As Dr. Ghia explains, DFS in the CAPTIVATE study was defined as a lack of progression and a lack of MRD relapse. This makes DFS much more stringent than PFS and allows researchers to assess deeper responses in this particular trial. 

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