Electra Therapeutics is seeking to raise as much as $341.9 million in a U.S. initial public offering, offering 21.7 million shares at $14 to $16 apiece and targeting a valuation of up to $977.6 million. At the midpoint, the South San Francisco-based biotech expects net proceeds of about $296.6 million, rising to $341.9 million if underwriters buy an additional 3.2 million shares. Electra plans to list on Nasdaq under the ticker ETRA, with Jefferies, TD Cowen, Evercore ISI and Cantor leading the offering. The company develops antibody drugs targeting signal regulatory proteins, or SIRPs. Its lead candidate, ipsoprubart, is a pan-SIRP monoclonal antibody being tested in a registrational phase 2/3 trial for secondary hemophagocytic lymphohistiocytosis, a rare and potentially fatal hyperinflammatory syndrome. Electra expects to allocate $220 million to that program and a potential regulatory application, alongside funding for additional ipsoprubart and ELA822 studies. The IPO comes during a strong year for biotech listings, even as the broader fall IPO market has faced macroeconomic uncertainty and volatility.