The combination of ofatumumab and lenalidomide is well-tolerated and induced durable responses in most patients with relapsed/refractory chronic lymphocytic leukemia (CLL), a study published in the journal Clinical Cancer Research has shown.1
For the phase 2 study, researchers sought to evaluate the efficacy and tolerability of the chemoimmunotherapy combination in patients with relapsed/refractory disease and investigate whether characteristics of the immune systems could impact treatment response.
Researchers enrolled 34 patients. All participants received ofatumumab 300 mg IV on day 1; 1000 mg on days 8, 15, and 22 during cycle 1; 1000 mg on day 1 during cycles 3 to 6; and once every other course during cycles 7 to 24. Cycles were 28 days long. Patients also started receiving lenalidomide 10 mg orally on day 9 until disease progression or unacceptable toxicity.
Results showed that the overall response rate was 71%. A total of 8 patients (24%) achieved a complete remission or complete remission with incomplete recovery of blood counts. That included 9% of patients who had a minimal residual disease-negative complete remission.
Researchers found that the median progression-free survival was 16 months and the estimated 5-year survival was 53%.
In terms of safety, the most common treatment-emergent toxicity was neutropenia, which was higher than grade 2 in 18% of the 574 patient cycles. The most frequently reported infectious complications of treatment were pneumonia (24%) and neutropenic fever (9%).
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The study demonstrated that patients who had higher baseline numbers and a better preserved function of T cells and natural killer cells were more likely to achieve a complete remission as compared with non-responders. This suggested that a competent immune system may play a role in supporting the efficacy of this therapy.
- Vitale C, Falchi L, ten Hacken E, et al. Ofatumumab and lenalidomide for patients with relapsed or refractory chronic lymphocytic leukemia: correlation between responses and immune characteristics [published online ahead of print January 5, 2016]. Clin Cancer Res. doi: 10.1158/1078-0432.CCR-15-2476.