Aug. 23 Quick Takes: Clinical hold sinks Foghorn

Additional suspected treatment-related patient deaths in the Phase I dose-escalation study of FHD-286 renewed concerns about the future of the BRG1/BRM inhibitor in its larger clinical indication, sending shares of Foghorn Therapeutics Inc. (NASDAQ:FHTX) down 25% to $11 on Tuesday. FDA placed a full clinical hold on the Phase I study to treat relapsed and/or refractory acute myelogenous leukemia (AML) and myelodysplastic syndrome (MDS) based on an undisclosed number of additional suspected cases of fatal differentiation syndrome — a known on-target adverse event for certain classes of AML/MDS therapies classes. In May, a partial clinical hold was placed on the study after one patient died of suspected differentiation syndrome. The hold does not affect a Phase I study of FHD-286 in uveal melanoma.

With its IPO filing late Tuesday, Third Harmonic Bio Inc. will soon see whether the market for new biotech listings has thawed sufficiently for the company to go public. The three-year-old company is advancing selective c-Kit inhibitor THB001 to treat allergic and mast cell-driven inflammatory indications; it is planning Phase Ib trials in chronic inducible urticaria and asthma. Morgan Stanley, Jefferies, Cowen and LifeSci Capital are underwriters; Atlas Venture is the biotech’s largest shareholder at 37.9%...