Is ibrutinib effective in relapsed or refractory mantle cell lymphoma?

This study examined the use of ibrutinib (Imbruvica) in patients with relapsed or refractory (did not respond to prior treatment) mantle cell lymphoma. The authors concluded that ibrutinib was a safe and effective treatment in these patients.

Mantle cell lymphoma is an aggressive form on non-Hodgkin lymphoma. Therapies such as chemotherapy, immunotherapies (those that stimulate the immune system to fight cancer cells) and stem cell (immature blood cell) transplantation have all improved outcomes. Most patients, however, will eventually relapse. New treatments are therefore needed.

Mantle cell lymphoma cells depend on a certain receptor (B cell) for growth. Ibrutinib is a Bruton’s tyrosine kinase inhibitor. The treatment inhibits (blocks) the B cell receptor. This can block cancer cell growth. The safety and effectiveness of ibrutinib in mantle cell lymphoma is still under investigation.

This study examined the use of ibrutinib in the treatment of relapsed and refractory mantle cell lymphoma. 111 patients were treated with at least one dose of ibrutinib, with an average of 9 doses. Patients were followed for an average of 15.3 months.

The overall response rate to treatment was 68%. A partial response (some decrease in cancer activity) was noted in 47%. A complete response (no sign of active disease) was seen 21%. In these patients, the average time to response was 1.9 months. The average time to complete response was 5.5 months. Overall, the average time to disease progression was 13.9 months.

Most side effects were minor. 50% of patients experienced diarrhea, 28% experienced swelling in the arms or legs, and 27% experienced shortness of breath. Other minor side effects that occurred in more than 20% of patients included constipation, upper respiratory tract infection, vomiting, and decreased appetite. The most common serious or severe side effect was pneumonia, in 6% of patients.

This study concluded that ibrutinib was a safe and effective treatment for patients with relapsed or refractory mantle cell lymphoma.

This study was funded in part by Pharmacyclics and Janssen Biotech, the manufacturers of ibrutinib.