X4 Pharma NDA Accepted for WHIM Syndrome

FDA has accepted for priority review an X4 Pharmaceuticals NDA for once-daily, oral mavorixafor to treat individuals aged 12 and older with WHIM (Warts, Hypogammaglobulinemia, Infections, and Myelokathexis) syndrome, a rare immunodeficiency. The agency has set a review action target date of 4/30/2024.

The NDA is based on data from the pivotal 4WHIM Phase 3 clinical trial, which met its primary endpoint of “time above threshold for absolute neutrophil count (TAT-ANC) vs. placebo (p<0.0001),” the company says. “The 4WHIM data also revealed that mavorixafor treatment resulted in reductions in the rate, severity, and duration of infections in trial participants versus placebo.”

Mavorixafor is described as an investigational small-molecule antagonist of the CXCR4 receptor. X4 Pharma says WHIM syndrome is caused by reduced mobilization and trafficking of white blood cells from the bone marrow due to over-signaling of the CXCR4/CXCL12 pathway.