Biotech Stocks Triple in Value Over One Year, Major Healthcare Fund Sells Partial Stake

Global biotech-focused investment firm OrbiMed recently sold approximately 510,000 shares of U.S.–listed cystic fibrosis drug developer Sionna Therapeutics, Inc. (NASDAQ: SION) on the open market under a prearranged Rule 10b5-1 trading plan, generating about $23 million in cash (roughly 30 billion Korean won). As a result, the indirect holdings of OrbiMed’s affiliated funds decreased from around 3.48 million shares to about 3.02 million shares. In an amended Schedule 13D filing, OrbiMed disclosed that it now holds roughly 2.967 million shares of Sionna common stock—about 6.6% of the company’s outstanding shares—and while it may buy or sell additional shares depending on market conditions, it confirmed it has no plans for activist actions related to management control, board representation, or capital structure.

Sionna’s stock reached an intraday all-time high of $45.17 in mid-April and has more than tripled over the past year. Earlier this month, the company continued its investor outreach to institutions, participating in the Raymond James 2026 Biotech Innovation Symposium and highlighting its full-year 2025 performance, announced in early March, as well as progress in its cystic fibrosis pipeline.

Sionna Therapeutics, Inc. (NASDAQ: SION) is a clinical-stage biotech developing small-molecule therapies to normalize the function of the cystic fibrosis transmembrane conductance regulator (CFTR) protein. Its lead candidates target the CFTR nucleotide-binding domain 1 (NBD1) and the F508del mutation, and are currently in early clinical trials. Since its founding in 2019, Sionna has expanded its pipeline with funding from global healthcare investors, including OrbiMed and RA Capital. According to recent disclosures, the company has secured sufficient financial resources to support the clinical advancement of its cystic fibrosis treatment candidates.