3 November, 2021, Shanghai—Abbisko Therapeutics Co., Ltd. (Stock Code: 2256.HK, “Abbisko” hereafter) today announces that its partner X4 Pharmaceuticals, Inc. has completed enrollment in the ongoing pivotal Phase 3 clinical trial of its lead candidate, mavorixafor, in the treatment of patients with genetically confirmed WHIM (warts, hypogammaglobulinemia, infections, and myelokathexis) syndrome, a primary immunodeficiency caused by gain-of-function mutations in the CXCR4 gene. Thirty-one adult and pediatric patients have enrolled in the 4WHIM trial, which compares a once-daily, oral dose of mavorixafor to placebo across primary and secondary endpoints that include clinically relevant counts of neutrophils and lymphocytes, the frequency and severity of both infections and warts, as well as certain quality of life measurements. The trial was originally designed to enroll 18-28 patients.

This was major milestone achievement for the thousands of WHIM patients with no disease-modifying treatment options. Top-line data from the 4WHIM trial is expected in the fourth quarter of 2022, and a regulatory filing likely will follow in the first quarter of 2023. In addition, we look forward to the availability of new long-term data from the ongoing Phase 2 open-label extension trial in WHIM as well as new research and clinical data later this year that may support broader market opportunities for mavorixafor across multiple indications.

Mavorixafor (ABSK081) is a first-in-class oral CXCR4 antagonist. Abbisko has obtained the exclusive rights in Greater China to develop and commercialize mavorixafor for oncology and WHIM indications. Abbisko will lead the clinical and commercial development of mavorixafor and has initiated the first of several planned clinical trials of mavorixafor in combination with other immuno-oncology or other therapeutic agents.

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