X4 Pharmaceuticals: Funding, Investors & Team (Oct 2026)
Leveraging our unparalleled expertise in diseases of the immune system and CXCR4 biology, we aim to bring innovative treatments to patients with chronic neutropenic disorders. Our lead product candidate, mavorixafor, is a first-in-class CXCR4 inhibitor being developed as a once-daily, oral therapy for people with chronic neutropenic disorders. Mavorixafor has demonstrated the ability to mobilize immune cells from the bone marrow into the bloodstream, creating what we believe to be broad commercial potential in the estimated 50,000 (U.S.) diagnosed chronic neutropenia patients who currently have few to no treatment options. We are currently evaluating the safety and efficacy of mavorixafor in a Phase 3 clinical trial for the treatment of people with WHIM syndrome; data from this Phase 3 study (4WHIM) are expected in the fourth quarter of 2022. We are also conducting a Phase 1b clinical trial of mavorixafor in people with idiopathic, cyclic, or congenital neutropenia. Based on positive data from the first part of this Phase 1b trial, we are currently amending and expanding the study to evaluate chronic use of daily oral mavorixafor with or without G-CSF in up to 50 participants with chronic neutropenic disorders. X4 is a public biopharmaceutical company (Nasdaq: XFOR) headquartered in Boston, Massachusetts, with a research center of excellence in Vienna, Austria.
X4 Pharmaceuticals has raised $420M across 4 funding rounds on record, the most recent an undisclosed round of $155M announced in Oct 2025.
That round is above the $8.4M median round size for Biotechnology companies tracked on FundedIQ over the last two years.
X4 Pharmaceuticals Company Profile and Key Stats
Latest funding round on record: Oct 2025.
X4 Pharmaceuticals Funding Rounds
X4 Pharmaceuticals raised $65.0M in an undisclosed round announced in Dec 2022.
8 months later, an undisclosed round of $115M was announced in Aug 2023.
2 years later, an undisclosed round of $85.0M was announced in Aug 2025.
2 months later, an undisclosed round of $155M was announced in Oct 2025.
X4 Pharmaceuticals Founders and Leadership Team
Contact details for the X4 Pharmaceuticals team: 1 of 1 has an email address on file.
Start 14-day free trial →X4 Pharmaceuticals Funding Compared to Other Biotechnology Startups
X4 Pharmaceuticals' latest round of $155M is above the median round in Biotechnology. Medians cover the last 24 months of disclosed rounds.
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X4 Pharmaceuticals Funding FAQs
What does X4 Pharmaceuticals do?
Leveraging our unparalleled expertise in diseases of the immune system and CXCR4 biology, we aim to bring innovative treatments to patients with chronic neutropenic disorders. Our lead product candidate, mavorixafor, is a first-in-class CXCR4 inhibitor being developed as a once-daily, oral therapy for people with chronic neutropenic disorders. Mavorixafor has demonstrated the ability to mobilize immune cells from the bone marrow into the bloodstream, creating what we believe to be broad commercial potential in the estimated 50,000 (U.S.) diagnosed chronic neutropenia patients who currently have few to no treatment options. We are currently evaluating the safety and efficacy of mavorixafor in a Phase 3 clinical trial for the treatment of people with WHIM syndrome; data from this Phase 3 study (4WHIM) are expected in the fourth quarter of 2022. We are also conducting a Phase 1b clinical trial of mavorixafor in people with idiopathic, cyclic, or congenital neutropenia. Based on positive data from the first part of this Phase 1b trial, we are currently amending and expanding the study to evaluate chronic use of daily oral mavorixafor with or without G-CSF in up to 50 participants with chronic neutropenic disorders. X4 is a public biopharmaceutical company (Nasdaq: XFOR) headquartered in Boston, Massachusetts, with a research center of excellence in Vienna, Austria.
How much funding has X4 Pharmaceuticals raised?
X4 Pharmaceuticals has raised $420M across 4 rounds on record. The most recent is an undisclosed round of $155M announced in Oct 2025.
When did X4 Pharmaceuticals last raise funding?
X4 Pharmaceuticals' most recent funding round on record is an undisclosed round of $155M, announced in Oct 2025.
Who is the CEO of X4 Pharmaceuticals?
Paula Ragan is listed as CEO at X4 Pharmaceuticals.
Where is X4 Pharmaceuticals headquartered?
X4 Pharmaceuticals is based in Cambridge, Massachusetts, United States.
How many employees does X4 Pharmaceuticals have?
X4 Pharmaceuticals is in the 51-100 employee band.
How does X4 Pharmaceuticals' funding compare to other Biotechnology startups?
X4 Pharmaceuticals' latest round of $155M is above the $8.4M median round size for Biotechnology companies on FundedIQ across 4,185 tracked companies over the last two years.
About FundedIQ's X4 Pharmaceuticals Funding Data
FundedIQ tracks announced funding rounds and refreshes this profile every week. Round dates, stages and amounts are normalised to a single format, converted to US dollars, and de-duplicated: two records of the same round announced days apart are merged, and two genuinely different rounds are kept apart on the amounts they disclose. Amounts shown are the disclosed figures only — a round announced without a number is listed and excluded from the total rather than estimated.
Employee counts are reported bands, not exact headcounts. Founder and executive names carry the job title on record. Anything we do not hold for X4 Pharmaceuticals is left off this page rather than filled in.
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