In November 2019, we announced the initiation of a
14-day, proof-of-concept Phase 1b clinical trial of mavorixafor in patients with severe congenital neutropenia, or SCN. We
currently expect that the reporting of initial data from the SCN trial will be delayed into 2021 due to delays in clinical site activation and the pace of enrollment caused by the COVID-19 pandemic. In
December 2019, we announced the initiation of a Phase 1b clinical trial of mavorixafor, in combination with ibrutinib, in patients with Waldenströms macroglobulinemia, or WM. We continue to expect to report initial data from the WM trial
by the end of 2020.
We are also advancing two early stage candidates towards the clinic: X4P-003,
a second-generation CXCR4 antagonist designed to have an enhanced pharmacokinetic profile relative to mavorixafor, potentially enabling improved patient compliance and ease of use; and X4P-002, a CXCR4
antagonist designed to cross blood-brain barrier and provide appropriate therapeutic exposures to treat brain cancers.
To date, we have
not generated revenue from product sales and do not expect to generate significant revenue from the sale of our products in the foreseeable future. If our development efforts for our product candidates are successful and result in regulatory
approval, we may generate revenue in the future from product sales. We cannot predict if, when, or to what extent we will generate revenue from the commercialization and sale of our product candidates. We may never succeed in obtaining regulatory
approval for any of our product candidates.
Corporate Information
Prior to March 13, 2019, we were a clinical-stage biopharmaceutical company known as Arsanis, Inc. that had historically been focused on
applying monoclonal antibody immunotherapies to address serious infectious diseases. Arsanis, Inc. was originally incorporated in the State of Delaware in August 2010.
On March 13, 2019, we completed our business combination with X4 Therapeutics, Inc. (formerly X4 Pharmaceuticals, Inc.) in accordance
with the terms of an Agreement and Plan of Merger, dated as of November 26, 2018, as amended on December 20, 2018 and March 8, 2019, or the Merger Agreement, that we entered into with X4 Therapeutics, Inc. and Artemis AC Corp., a
Delaware corporation and our wholly owned subsidiary, or Merger Sub. Pursuant to the terms of the Merger Agreement, Merger Sub merged with and into X4 Therapeutics, Inc., with X4 Therapeutics, Inc. continuing as our wholly owned subsidiary and the
surviving corporation of the merger, which transaction we refer to as the Merger. At the closing of the Merger, we issued shares of our common stock to X4 Therapeutics, Inc. stockholders based on an agreed upon exchange ratio, and each option or
warrant to purchase X4 Therapeutics, Inc. capital stock became an option or warrant, respectively, to purchase our common stock, subject to adjustment in accordance with the agreed upon exchange ratio. Following the closing of the Merger, we
effected a 1-for-6 reverse stock split of our common stock, or the Reverse Stock Split, our name was changed to X4 Pharmaceuticals, Inc., the business of X4
Therapeutics, Inc. became our business, and we became a clinical-stage biopharmaceutical company focused on the discovery, development and commercialization of novel therapeutics for the treatment of rare diseases. In connection with the closing of
the Merger, our stock began trading on the Nasdaq Capital Market under the symbol XFOR on March 14, 2019.
Our principal executive
offices are located at 955 Massachusetts Avenue, 4th Floor, Cambridge, Massachusetts 02139, and our telephone number is (857) 529-8300. Our website is
located at http://www.x4pharma.com. We do not incorporate by reference into this prospectus the information on, or accessible through, our website, and you should not consider it as part of this prospectus.
The Securities We May Offer
We may offer shares of our common stock and preferred stock, various series of debt securities and warrants to purchase any of such
securities, up to a total aggregate offering price of $150,000,000 from time to time in one