Study of mechanism of ibrutinib action in mantle cell lymphoma

A study that investigated the mechanism of ibrutinib's anti-tumor effect in patients with mantle cell lymphoma (MCL) has been published in Blood, the most cited peer-reviewed journal in the field of hematology. The drug is under development by USA-based Pharmacyclics (Nasdaq: PCYC) and partner Janssen Pharmaceuticals, a unit of Johnson & Johnson (NYSE: JNJ).

Response of MCL patients to ibrutinib was noted during early clinical trials to be accompanied by increases in absolute lymphocyte count (ALC) in the peripheral blood. MCL cells typically grow in the lymph nodes and tissues where they receive signals and support that are essential for their survival and growth.

In the current paper, Pharmacyclics vice president of research, Betty Chang, along with colleagues and collaborators, showed that the lymphocytes, which increase in the peripheral blood during ibrutinib treatment, are MCL cells rather than normal cells. Moreover, the data indicate ibrutinib may directly and potently inhibit MCL cell adhesion and migration in the residing lymph nodes or tissues. This publication illustrates these cells show decreases of markers of activation and growth as treatment continued and nodal responses were observed.