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X4 Pharmaceuticals Announces FDA Fast Track Designation Granted to Mavorixafor for the Treatment of WHIM Syndrome

Current TAP Partner


BOSTON, Oct. 08, 2020 (GLOBE NEWSWIRE) -- X4 Pharmaceuticals, Inc. (Nasdaq: XFOR), a leader in the discovery and development of novel therapies targeting diseases resulting from dysfunction of the CXCR4 pathway, today announced that the U.S. Food and Drug Administration (FDA) has granted Fast Track Designation to its lead asset, mavorixafor, for the treatment of adult patients with WHIM (Warts, Hypogammaglobulinemia, Infections, and Myelokathexis) syndrome, a rare, inherited, primary immunodeficiency disease caused by genetic mutations in the CXCR4 receptor gene.

Mavorixafor is a potential first-in-class, once-daily, oral, small molecule antagonist of chemokine receptor CXCR4, currently being investigated in a global pivotal Phase 3 clinical trial, 4WHIM, for the treatment of WHIM syndrome and in two Phase 1b clinical trials – in combination with ibrutinib in patients with Waldenstrom macroglobulinemia (WM), and as monotherapy in patients with severe congenital neutropenia (SCN).

The Fast Track Designation aims to facilitate the expedited development and review of new drugs that are intended to treat serious or life-threatening conditions and demonstrate the potential to address unmet medical needs. Through the Fast Track program, X4 will be eligible for more frequent meetings with the FDA to discuss the drug’s development plan, protocols and clinical data that would support mavorixafor’s potential approval for WHIM.

In addition to Fast Track Designation, mavorixafor was previously granted Breakthrough Therapy Designation by the FDA, as well as Orphan Drug status by the FDA and the European Commission for the treatment of WHIM syndrome.

The Leukemia & Lymphoma Society (LLS) partnered with X4 in March 2019 to accelerate the development of mavorixafor for the treatment of WM and a Phase 1b clinical trial was initiated in December 2019. Mavorixafor was selected for the LLS Therapy Acceleration Program® (TAP), a strategic initiative where LLS builds business alliances and collaborations with biotechnology companies and academic researchers to speed the development of new therapies for blood cancers.