Ibrutinib produces durable disease control for patients with high-risk hairy cell leukemia, a rare cancer, who have relapsed and for whom standard purine analogues are not a feasible therapeutic option, according to study results published in Blood.
In the phase II, multisite, open-label, single-agent clinical trial, researchers evaluated the effectiveness of ibrutinib, an oral Bruton’s tyrosine kinase (BTK) inhibitor, in 44 patients with relapsed classic or variant hairy cell leukemia.
After a median 3.5 years of follow-up (range = 0–5.9 years), overall response rate was 24% at 32 weeks, 36% at 48 weeks, and 54% at peak. The estimated 36-month progression-free survival was 73% and overall survival was 85%. The most frequent adverse events were diarrhea (59%), fatigue (54%), myalgia (54%), nausea (51%), and hematologic events such as anemia (43%), thrombocytopenia (41%), and neutropenia (35%).
“There is a critical unmet need for therapy options in this subset of patients to achieve long-term cancer control,” the authors said. “Our study shows that ibrutinib is a safe, effective, and well-tolerated option for patients with relapsed or variant forms of hairy cell leukemia. It is a very important discovery for patients facing this diagnosis. It’s a very exciting development that could transform survivorship for this subset of patients from months and years to years and decades.”