FDA approves Imbruvica for Waldenstrom's macroglobulinemia - Pharmacyclics

The FDA has approved an expanded indication of Imbruvica (ibrutinib), from Pharmacyclics, for the treatment of Waldenstrom's macroglobulinemia (WM). The drug was granted expanded approval under the breakthrough therapy designation.

The FDA based its approval of Imbruvica for WM on a clinical study of 63 previously treated participants. All study participants received a daily 420 milligram orally administered dose of the medication until disease progression or side effects became intolerable. Results showed 62 percent of participants had their cancer shrink after treatment (overall response rate). At the time of the study, the duration of response ranged from 2.8 months to approximately 18.8 months.

The most common side effects associated with the drug are low blood platelet counts (thrombocytopenia), a decrease in infection-fighting white blood cells (neutropenia), diarrhea, low red blood cell counts (anemia), lack of energy (fatigue), musculoskeletal pain, bruising, nausea, upper respiratory tract infection, and rash.