John C. Byrd, MD, a professor of Medicine at The Ohio State University Comprehensive Cancer Center, discusses the promising findings from the phase III RESONATE trial that compared ibrutinib to ofatumumab in patients with relapsed or refractory chronic lymphocytic leukemia (CLL).
The phase III study randomized 391 patients with relapsed/refractory CLL in a 1:1 ratio to ibrutinib or ofatumumab. The primary endpoint was progression-free survival (PFS), with secondary endpoints looking at overall survival (OS), objective response rate (ORR), and safety.
PFS was significantly extended, with a phenomenal hazard ratio of 0.22, Byrd notes. At 6 months, 88% of patients treated with ibrutinib remained progression-free compared with 65% with ofatumumab. At one year, the OS rate was 90% versus 81%, for ibrutinib and ofatumumab, respectively. This advantage was demonstrated despite 57 patients crossing over from treatment with ofatumumab to ibrutinib, Byrd notes. Additionally, response was considerably higher with ibrutinib across all study populations, including high-risk groups.
In general, both arms of therapy were acceptably tolerated, Byrd notes. However, there were some side effects that were more closely associated with ibrutinib, such as low-grade infections, bruising, blurred vision, atrial fibrillation, and diarrhea. Interestingly, in the study, patients receiving ofatumumab experienced peripheral neuropathy, which is not generally associated with this therapy, Byrd points out.
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