X4 Pharmaceuticals to Host 2020 Analyst Day Webinar: A Deep Dive into WHIM Syndrome

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 it will host a virtual Analyst Day to discuss its strategic focus on WHIM (Warts, Hypogammaglobulinemia, Infections, and Myelokathexis) syndrome, a rare, inherited, primary immunodeficiency disease the Company is targeting with its Phase 3 clinical candidate mavorixafor.

The event will include an opportunity to hear directly from a WHIM patient, and a presentation and Q&A session with David C. Dale, M.D., a pioneer in the study and treatment of congenital neutropenia and Professor of Medicine at the University of Washington School of Medicine, who has substantial experience treating WHIM patients. The Company will also provide an update on results from its market research efforts supporting the estimated U.S. WHIM patient prevalence. There will be a live Q&A session to follow as part of the event.

The event will begin at 8:00 a.m. Eastern Time on Tuesday, April 7, 2020. The webcast and slides will be accessible live under "Events & Presentations" on the Investors page of the Company's website at www.x4pharma.com. Individuals can participate in the conference call by dialing (866) 721-7655 (domestic) or (409) 216-0009 (international), followed by the conference ID: 3097608. A replay of the webinar will be available on the X4 website approximately two hours after the webinar has concluded.

About X4 Pharmaceuticals

X4 Pharmaceuticals is a late-stage clinical biopharmaceutical company and a leader in the discovery and development of novel therapies for the treatment of diseases resulting from dysfunction of the CXCR4 pathway, with a focus on rare diseases and those with limited treatment options. The Company's lead candidate, mavorixafor, is a first-in-class, oral, small molecule antagonist of chemokine receptor CXCR4. X4 believes that inhibition of the CXCR4 receptor creates the potential for mavorixafor to provide therapeutic benefit across a wide variety of diseases, including primary immunodeficiencies and certain types of cancer. The efficacy and safety of mavorixafor, dosed once daily, is currently being evaluated in a global Phase 3 clinical trial in patients with WHIM syndrome, and in two Phase 1b clinical trials ? as monotherapy in patients with Severe Congenital Neutropenia (SCN) and in combination with ibrutinib in patients with Waldenström's macroglobulinemia. X4 is continuing to leverage its insights into CXCR4 biology at its corporate headquarters in Cambridge, Massachusetts and at its research facility in Vienna, Austria, and is discovering and developing additional product candidates. For more information, please visit www.x4pharma.com.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, as amended. These statements may be identified by the words "may," "will," "could," "would," "should," "expect," "plan," "anticipate," "intend," "believe," "estimate," "predict," "project," "potential," "continue," "target" or other similar terms or expressions that concern X4's expectations, strategy, plans or intentions. Forward-looking statements include, without limitation, statements regarding X4's clinical trials relating to WHIM, SCN and Waldenström's macroglobulinemia. These statements are subject to various risks and uncertainties including, without limitation, the risk that trials and studies may be delayed and may not have satisfactory outcomes, potential adverse effects arising from the testing or use of mavorixafor or other product candidates, and the risk that costs required to develop product candidates or to expand X4's operations will be higher than anticipated. Any forward-looking statements in this press release are based on management's current expectations and beliefs. Actual events or results may differ materially from those expressed or implied by any forward-looking statements contained herein, including, without limitation, the risks and uncertainties described in the section entitled "Risk Factors" in X4's Annual Report on Form 10-K filed with the Securities and Exchange Commission (SEC) on March 12, 2020, and in other filings X4 makes with the EC from time to time. X4 undertakes no obligation to update the information contained in this press release to reflect new events or circumstances, except as required by law.