The US Food and Drug Administration (FDA) has accepted for priority review a supplemental new drug application (sNDA) for ibrutinib (Imbruvica®) to be used in combination with rituximab in patients with Waldenström’s macroglobulinemia (WM).
The FDA intends to take action on a priority review application within 6 months of receiving it, rather than the standard 10 months.
The FDA grants priority review to applications for products that may provide significant improvements in the treatment, diagnosis, or prevention of serious conditions.
Ibrutinib is a first-in-class Bruton’s tyrosine kinase inhibitor jointly developed and commercialized by Pharmacyclics LLC, an AbbVie company, and Janssen Biotech, Inc.
Ibrutinib is already FDA-approved to treat chronic lymphocytic leukemia/small lymphocytic lymphoma, previously treated mantle cell lymphoma, previously treated marginal zone lymphoma, previously treated chronic graft-versus-host disease, and WM.
If the new sNDA is approved, the use of ibrutinib in WM will extend beyond its current approved use as a single agent.
Phase 3 trial
The sNDA for ibrutinib and rituximab in WM is supported by data from the phase 3 iNNOVATE study. Results from this trial were presented at the 2018 ASCO Annual Meeting (abstract 8003) and were simultaneously published in NEJM.
iNNOVATE is a placebo-controlled, double-blind, phase 3 study that enrolled 150 patients with relapsed/refractory and treatment-naïve WM.
All patients received rituximab at 375 mg/m2 with weekly infusions at weeks 1 to 4 and 17 to 20. They also received either ibrutinib (420 mg) or placebo once daily continuously until criteria for permanent discontinuation were met.
Overall response rates were significantly higher in the ibrutinib arm than the placebo arm—92% and 47%, respectively (P<0.0001). Complete response rates were 3% and 1%, respectively.
The median time to next treatment was not reached for the ibrutinib arm and was 18 months for the placebo arm (hazard ratio=0.096; P<0.0001). Of the patients randomized to ibrutinib plus rituximab, 75% continued on treatment at last follow-up.
The 30-month progression-free survival rates were 82% in the ibrutinib arm and 28% in the placebo arm. The median progression-free survival was not reached in the ibrutinib arm and was 20.3 months in the placebo arm (hazard ratio=0.20; P<0.0001).
The 30-month overall survival rates were 94% in the ibrutinib arm and 92% in the placebo arm.
Grade 3 or higher treatment-emergent adverse events (AEs) occurred in 60% of patients in the ibrutinib arm and 61% in the placebo arm.
Serious AEs occurred in 43% and 33% of patients, respectively. There were no fatal AEs in the ibrutinib arm and 3 in the rituximab arm.
Grade 3 or higher AEs that occurred more frequently in the ibrutinib arm than the placebo arm included atrial fibrillation (12% vs 1%) and hypertension (13% vs 4%).
AEs that occurred less frequently in the ibrutinib arm than the placebo arm included grade 3 or higher infusion reactions (1% vs 16%) and any-grade IgM flare (8% vs 47%).