X4 Pharmaceuticals shares surge 11.38% intraday after FDA approves Xolremdi for WHIM syndrome.

X4 Pharmaceuticals surged 11.38% intraday, as the FDA approved Xolremdi for WHIM syndrome on December 4, 2025. The company focuses on developing and commercializing novel therapies for rare immune system diseases, with core products including the approved XOLREMDI and mavorixafor in Phase 3 clinical trials.