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Oral Ibrutinib (Imbruvica) Reduces Disease Progression Versus IV Temsirolimus in Lymphoma Patients
Ibrutinib (Imbruvica, Pharmacyclics/Janssen Biotech) significantly prolonged progression-free survival (PFS) and improved overall response rates (ORRs) compared with temsirolimus (Torisel, Pfizer) in a head-to-head phase III study of patients with relapsed or refractory mantle cell lymphoma (MCL). In a key finding, ibrutinib was associated with a significant reduction in the risk of disease progression or death. The new findings were published online in The Lancet.
MCL is an aggressive form of blood cancer that arises from B cells, a type of lymphocyte that originates in the bone marrow. MCL is more prevalent in men than in women. Most patients are in their mid-60s at diagnosis, and the median overall survival rate is 3 to 4 years.
In the open-label RAY trial, 280 patients with relapsed or refractory MCL were randomly assigned to receive either oral ibrutinib 560 mg in accordance with the approved product label (n = 139) or intravenous temsirolimus (175 mg on days 1, 8, and 15 of cycle 1, and 75 mg on days 1, 8, and 15 of all subsequent 21-day cycles; n = 141) until disease progression or unacceptable toxicity occurred.
Ibrutinib significantly improved PFS (the study’s primary endpoint) compared with temsirolimus, resulting in a 57% reduction in the risk of disease progression or death after a median follow-up period of 20 months (hazard ratio, 0.43; P < 0.0001). The median PFS for ibrutinib-treated patients was 14.6 months compared with 6.2 months for patients treated with temsirolimus. Ibrutinib was also associated with a significantly higher ORR compared with temsirolimus (72% vs. 40%, respectively; P < 0.0001). Twenty-six patients (19%) who received ibrutinib achieved a complete response (CR), whereas only two patients (1%) who received temsirolimus experienced a CR. The median treatment duration was four times longer in patients receiving ibrutinib than in those receiving temsirolimus (14.4 months vs. 3.0 months, respectively). Median overall survival was not reached with ibrutinib, compared with 21.3 months with temsirolimus (HR, 0.76).
The most common treatment-emergent adverse events (AEs) in ibrutinib-treated patients included diarrhea (29%), cough (22%), and fatigue (22%), and the most common AEs in the temsirolimus group included thrombocytopenia (56%), anemia (43%), diarrhea (31%), fatigue (29%), neutropenia (26%), epistaxis (24%), cough (22%), peripheral edema (22%) nausea (22%), pyrexia (21%), and stomatitis (21%). The most common hematological AEs included thrombocytopenia (18% for ibrutinib vs. 56% for temsirolimus), anemia (18% vs. 43%), and neutropenia (16% vs. 26%). Overall, 7% of the ibrutinib-treated patients and 26% of the temsirolimus-treated patients discontinued treatment because of AEs. After a median follow-up period of 20 months, 42% of the ibrutinib-treated patients had died compared with 45% of the temsirolimus-treated patients.
Source: AbbVie; December 7, 2015.