In mantle cell lymphoma (MCL), ibrutinib plus venetoclax significantly improved the complete response rate, compared with what has been previously reported for ibrutinib alone, according to results of a phase 2 study.
Clinical outcomes with the combination seem superior to previously reported results for either treatment alone, said lead investigator, of the Peter MacCallum Cancer Centre, Melbourne, and his coinvestigators.
“The results of our study, which used a historical cohort as a control, are consistent with the notion that the combination of ibrutinib and venetoclax is highly effective in mantle-cell lymphoma,” the investigators wrote in the.
The BTK inhibitor ibrutinib and the BCL2 inhibitor venetoclax are two of the most active agents for this B-cell cancer, investigators reported. The rationale for combining the agents is “compelling” because they affect different critical pathways in the malignant B cell.
Both agents have demonstrated complete response rates of 21% in previous studies of relapsed or refractory MCL, and preclinical studies suggest the combination of ibrutinib and venetoclax would be synergistic.
In the present single-group, phase 2 study, 24 patients with MCL (23 relapsed or refractory, 1 previously untreated) started ibrutinib 560 mg daily; at 4 weeks, venetoclax was started at a low dose and increased to 400 mg daily.
The study primary end point – complete response rate at week 16 assessed by CT – was 42%, compared with 9% for ibrutinib monotherapy in the phase 2(P less than .001).