Ibrutinib may prove useful in MM, research shows

Treatment-emergent non-hematologic AEs of any grade in cohort 4 occurring in more than 20% of patients included diarrhea (63%), fatigue (49%), cough (26%), nausea (23%), and muscle spasms (21%). Two percent of patients had grade 3/4 diarrhea. There were no other grade 3/4 adverse events in the cohort.

Eighty-six percent of patients in cohort 4 discontinued treatment, 60% due to progressive disease, 12% due to an AE, and 2% at the discretion of the investigator. Twelve percent withdrew, were noncompliant, or required concomitant medication that was not permitted by the protocol.

Overall, Dr Richardson said, the safety profile was manageable, similar across the dosing cohorts, and consistent with those seen in CLL and Waldenström’s macroglobulinemia. The 840-mg dose did not increase toxicity and demonstrated activity in this heavily pretreated population.

“The real signal that struck us,” Dr Richardson emphasized, “was the progression-free survival at 5.4 months . . . for a 92-patient, multicenter experience, this is obviously, I think, an encouraging start.”

Investigators continue to explore ibrutinib in 2 ongoing combination studies, one with carfilzomib and dexamethasone (PCYC-1119) and another with pomalidomide and dexamethasone (PCYC-1138). Another trial with lenalidomide and dexamethasone is planned.

Ibrutinib now has 4 FDA-approved indications: patients with CLL who have received at least 1 prior therapy, CLL patients with del 17p, patients with mantle cell lymphoma, and patients with Waldenström’s macroglobulinemia.

Ibrutinib is distributed and marketed as Imbruvica by Pharmacyclics and also marketed by Janssen Biotech, Inc.