Dr. Jacobs on the Efficacy of Ibrutinib and Acalabrutinib in Patients With MCL

Ryan W. Jacobs, MD, physician, Levine Cancer Institute, discusses the efficacy of ibrutinib (Imbruvica) and acalabrutinib (Calquence) in patients with mantle cell lymphoma (MCL).

When looking at the numbers for acalabrutinib, the response rate data appear to be stronger than that of ibrutinib, says Jacobs. However, when you look at the patient populations, the study of ibrutinib was a refractory group who had a median of 3 prior treatments. The paper on acalabrutinib had a median of 2 prior treatments, so the patients in the ibrutinib paper were significantly more refractory than those in the acalabrutinib paper.

It is questionable whether 1 agent is better than the other, says Jacobs. There is no indication that a patient who has progressed on ibrutinib would respond to acalabrutinib, as the agents hit the same binding spot on the BTK (C481S). However, acalabrutinib may be a good option for a patient who becomes intolerant to ibrutinib.

Physicians will get an answer, at least on the chronic lymphocytic leukemia (CLL) side because there is a large phase III trial which has completed accrual. This trial will be a head-to-head comparison of ibrutinib and acalabrutinib in patients with relapsed CLL, says Jacobs.