X4 Pharmaceuticals, Inc. announced an update to its strategic priorities that includes streamlining resources to focus on advancing its lead clinical candidate, mavorixafor, in WHIM syndrome and other chronic neutropenic disorders, while progressing its clinical and pre-clinical oncology programs only via potential partnership(s). Sharpening corporate focus and prioritizing resources towards immunodeficiency-related clinical programs: WHIM Syndrome: Data readout from the pivotal Phase 3 4WHIM trial of once-daily, oral mavorixafor in individuals 12 and older with WHIM (Warts, Hypogammaglobulinemia, Infections, & Myelokathexis) syndrome expected in the fourth quarter of 2022; U.S. New Drug Application (NDA) submission now anticipated early in the second half of 2023. Chronic Neutropenic (CN) Disorders: Results from the Phase 1b study of mavorixafor in individuals with CN disorders anticipated in the third quarter of 2022; data expected to confirm broad potential of mavorixafor to treat CN disorders beyond WHIM, to support discussions with the U.S. Food & Drug Administration (FDA) on next steps, and to inform the regulatory path forward.

X4P-003: The candidate, a novel, small-molecule CXCR4 antagonist, has progressed to pre-clinical development and patent applications have been filed; further advancement dependent on the potential first approval of mavorixafor and lifecycle management of the company's product portfolio. Progressing oncology efforts only via potential partnership(s) for the company's clinical and pre-clinical programs: Waldenström's macroglobulinemia (WM): Additional Phase 1b clinical data anticipated in early August 2022 in patients with WM caused by both MYD88 and CXCR4 mutations; recently disclosed preclinical data highlight broad potential for treatment of leukemias and lymphomas in wild-type CXCR4; mavorixafor recently granted Orphan Drug Designation by the FDA for treatment of WM regardless of CXCR4 mutation status; new clinical trials in WM will now be subject to completing a strategic partnership. X4P-002: IND-enabling toxicology studies are being finalized for the pre-clinical candidate, a novel, small-molecule CXCR4 antagonist that has demonstrated potential across a number of leukemias and lymphomas and that has been shown to cross the blood-brain barrier; IND filing will now be subject to completing a strategic partnership.

Reducing operating expenses through discontinuation of further work on oncology programs and a workforce reduction of approximately 20%; measures are expected to result in an estimated $5 million reduction in expenditures in 2022 and a $20 million reduction in expenditures in 2023. Extending X4's cash runway into the third quarter of 2023 as a result of the company's recent $55 million capital raise, the recently completed amendment to X4's debt facility (which is expected to result in cash savings of up to $20 million over the interest-only period), and implementation of the announced cost reductions.