X4 Secures up to $150 Million in Debt Financing as Chronic Neutropenia Trial Advances

Rare Daily Staff

X4 Pharmaceuticals said it has entered into a loan agreement with K2 HealthVentures worth up to $150 million, refinancing its existing debt as it prepares for key clinical milestones and a potential expansion of the use of its drug mavorixafor to treat chronic neutropenia.

The company said it received $80 million when the agreement closed. That initial funding went toward paying off its previous loan, including $75 million in principal, and covering related fees and closing costs.

X4 may request the remaining $70 million, but access to those funds depends on K2 HealthVentures’ approval and other conditions.

The new agreement gives X4 a larger borrowing facility, a longer interest-only payment period, and a four-year term before the loan matures. The company said the financing will support corporate and commercial activities, including a potential launch of mavorixafor for chronic neutropenia if the drug wins regulatory approval for that use.

“Our partnership with K2 HealthVentures strengthens our capital position and gives us a solid financial foundation as we advance mavorixafor toward potential FDA approval and a commercial launch in chronic neutropenia,” said David Kirske, X4’s CFO.

X4 expects to finish enrolling patients in its global phase 3 trial, called 4WARD, by the end of 2026 and report initial results in the first half of 2028. The study is evaluating mavorixafor in chronic neutropenic disorders.

Mavorixafor is already approved in the United States and European Union under the brand name Xolremdi for patients with WHIM syndrome, a rare disease. The company is seeking to broaden the drug’s use and has received FDA Fast Track designation for its development in chronic neutropenia.

The financing announcement does not mean that X4 has received $150 million in new cash for operations: the initial $80 million was used to refinance existing obligations and cover transaction costs, while the additional borrowing remains conditional.

X4 also cautioned that access to further funding depends on meeting loan requirements, including minimum cash and revenue conditions. An extension of the interest-only period depends on the timing of the first U.S. commercial sales of mavorixafor for chronic neutropenia. Changes in the prime rate could increase interest costs.