Drug developers Retension Pharmaceuticals and TRex Bio filed paperwork Friday for U.S. initial public offerings, adding to a biotech IPO pipeline that analysts say has benefited from acquisitions by large drugmakers. The offerings would expand a fall IPO slate that has started unevenly as higher bond yields and the Federal Reserve’s monetary policy tightening cycle weigh on investor sentiment. South San Francisco-based TRex Bio is developing treatments intended to restore immune balance and support tissue repair for autoimmune and inflammatory diseases. Its leading candidate, TRB-061, is in an early-stage clinical trial across several such diseases, with data expected in mid-2027. Eli Lilly plans to invest in TRex’s IPO, its prospectus says. Retension Pharmaceuticals, based in Falls Church, Virginia, is developing treatments for hypertension and other cardiovascular conditions. Its sole hypertension candidate, RTN-001, produced significant blood-pressure reductions in two mid-stage trials. TRex plans to list on Nasdaq under the symbol TRXB, while Retension plans to use RTSN. Electra Therapeutics, another late-stage drug developer, began trading in New York on Friday after raising $350 million in an upsized U.S. IPO.