X4 Pharmaceuticals stock falls 9.33 percent to USD 3.11

X4 Pharmaceuticals stock was quoted at USD 3.11 after hours on Nasdaq on September 23, 2026, down 9.33 percent from the prior close. The latest clinical update dated September 8, 2026, reduced the planned 4WARD Phase 3 enrollment from 176 to 126 participants.

Trial plan cuts enrollment

According to Stock Titan, X4 Pharmaceuticals said on September 8, 2026, that the U.S. Food and Drug Administration agreed to the smaller patient group while maintaining statistical power for the trial's co-primary endpoints. The reduction equals 50 participants, or 28.4 percent of the former target.

The same update points to enrollment completion by the end of 2026 and top-line data in the first half of 2028. For investors, the smaller study design changes the development timetable's execution burden, while the 2028 data date keeps the main value driver tied to clinical progress rather than near-term earnings.

Q2 revenue jumps 225.1 percent

X4's Q2 2026 revenue reached USD 8.806 million, compared with USD 2.708 million in Q1 2026, an increase of 225.1 percent. Quartr also reported that the Q2 net loss improved to USD 16.157 million from USD 20.241 million in Q1 2026.

The revenue comparison is meaningful because X4 is commercializing XOLREMDI in the United States while advancing mavorixafor in chronic neutropenic disorders. The company's investor materials describe a global pivotal Phase 3 trial and identify mavorixafor as an orally available CXCR4 antagonist.

Stock trades near yearly floor

At USD 3.11 after hours on September 23, 2026, the stock stood USD 0.31 above its 52-week low of USD 2.80 and USD 1.72 below its 52-week high of USD 4.83. X4 Pharmaceuticals had a market capitalization of USD 293,334,255 on the same date.