X4 Pharmaceuticals develops mavorixafor, a therapy for rare immune-system diseases that is already marketed in the U.S. as XOLREMDI for its first indication. The company is conducting a global phase 3 trial (4WARD) evaluating mavorixafor for chronic neutropenia and reported positive phase 2 data from a 23‑patient study presented at EHA. The FDA has granted Fast Track designation for mavorixafor in chronic neutropenia, and full recruitment for the phase 3 trial is expected later this year. X4 plans to use proceeds from the financing to pursue additional potential approvals of mavorixafor and to support commercialization efforts. Financially, InvestingPro data show a negative free cash flow of -6.75% and a forecasted EPS of -13.11 for the year, while the company maintains a current ratio of 3.19. The stock has traded near a 52‑week low of $1.35 after falling more than 90% over the past six months. X4 Pharmaceuticals is a clinical-stage biotechnology company developing oral small-molecule CXCR4 inhibitors to improve immune cell trafficking and immune surveillance in cancer and rare diseases. Its two lead candidates are X4P-001-IO (immuno-oncology) and X4P-001-RD (rare disease for WHIM syndrome). X4P-001-IO has shown encouraging Phase 1/2 results in refractory clear cell renal cell carcinoma and signals of immune activation in melanoma, while X4P-001-RD has demonstrated initial proof-of-concept in the Phase 2 portion of an ongoing Phase 2/3 study in WHIM syndrome. The company plans to advance X4P-001-RD into a pivotal study in WHIM syndrome in 2018 and to continue proof-of-concept studies in oncology. Founded in 2015 and based in Cambridge, MA, X4 entered clinical studies rapidly within two years of launching. Proceeds from its completed $27 million Series B will be used to fund these clinical efficacy and pivotal studies. X4 is developing oral small‑molecule inhibitors of the CXCR4 receptor aimed at improving immune cell trafficking and restoring T‑cell surveillance in cancer. Its lead candidate, X4P‑001, was slated to enter Phase 1/2 testing in refractory clear cell renal cell carcinoma (ccRCC) and other solid tumors in 2016. A second program, X4P‑002, is in preclinical development targeting brain cancers and was expected to enter the clinic in 2017. The company’s drug compounds are exclusively licensed from Sanofi. X4 closed a $37.5 million Series A to initially fund development of its CXCR4 pipeline. The company is led by CEO Paula Ragan and a leadership team with multiple former Genzyme executives and is located in Cambridge, MA.

Total raised

$125M

Funding rounds

3

Latest round

Equity

Latest activity

Aug 2025