Ibrutinib combined with ofatumumab is well-tolerated and active in patients with relapsed chronic lymphocytic leukemia (CLL), a new study published online ahead of print in the journal Blood has shown.

The combination also resulted in a quicker time to best response than single-agent ibrutinib and durable responses.

For the study, researchers sought to evaluate the safety and activity of the combination of ibrutinib and ofatumumab in three different administration sequences in patients with relapsed CLL/small lymphocytic leukemia (SLL), prolymphocytic leukemia, or Richter’s transformation who failed two or more prior therapies.

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Researchers enrolled 71 patients, most of which had high-risk disease. Participants received ibrutinib 420 mg orally daily and 12 doses of ofatumumab 300/2,000 mg intravenously in three schedules. Patients either received lead-in ibrutinib, a concurrent start, or ofatumumab lead-in.

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Results showed that the most common adverse events were diarrhea, infusion-related reaction, and peripheral sensory neuropathy.

In regard to activity, the overall response rates in patients with CLL/SLL were 100% in the ibrutinib lead-in group, 79% in the concurrent start group, and 71% in the ofatumumab lead-in group.

Researchers found that four patients in the ofatumumab lead-in arm experienced disease progression prior to ibrutinib initiation.


  1. Jaglowski SM, Jones JA, Nagar V, et al. Safety and activity of BTK inhibitor ibrutinib combined with ofatumumab in chronic lymphocytic leukemia: a phase 1b/2 study. Blood. 2015. [epub ahead of print]. doi: 10.1182/blood-2014-12-617522.