Astria Therapeutics, Inc. (ATXS)

Astria Therapeutics, Inc. was a clinical-stage biopharmaceutical company based in Boston, Massachusetts, focused on allergic and immunological diseases, particularly hereditary angioedema (HAE). HAE is a rare genetic disorder that causes recurrent episodes of swelling. The company aimed to develop long-acting preventive treatments that patients could take less frequently than existing options.

Astria was founded in 2008 as Catabasis Pharmaceuticals, which listed on Nasdaq in 2015 and developed drug candidates for other conditions. After clinical setbacks, the company reoriented itself. In 2021 it acquired Quellis Biosciences, adding an HAE antibody program, and renamed itself Astria Therapeutics in September 2021.

Its lead program was navenibart, previously called STAR-0215, a long-acting monoclonal antibody that inhibits plasma kallikrein. The company designed it for dosing as infrequently as every three to six months. Astria advanced the drug through early-stage trials and into a late-stage study in HAE, and it also had a preclinical program for a different HAE target.

The company had no approved product and funded its operations through equity offerings and cash reserves. Its common stock traded on Nasdaq under the symbol ATXS. Competition in HAE included established prophylactic therapies and newer candidates from larger companies.

On October 14, 2025, BioCryst Pharmaceuticals, Inc. announced a definitive agreement to acquire Astria. Each Astria common share was to be converted into 0.59 of a share of BioCryst common stock plus $8.55 in cash, without interest. The companies noted that the deal would extend BioCryst's HAE franchise beyond its marketed oral therapy.

The merger closed on January 23, 2026, when Astria combined with a BioCryst subsidiary and became a wholly owned subsidiary of BioCryst. According to an SEC filing, Astria asked Nasdaq to suspend trading before the market opened that day and to file a Form 25 to delist its common stock and deregister it under Section 12(b). Astria then planned to file a Form 15 to suspend its reporting obligations.

The transaction gave Astria shareholders a combination of cash and stock in BioCryst, so part of their value after closing depended on the performance of BioCryst's shares, which continue to trade on Nasdaq under the symbol BCRX. For BioCryst, the deal added a late-stage HAE candidate to its portfolio. After the merger Astria's shares ceased to be quoted, and the former Astria operations became part of BioCryst, which is based in North Carolina. Hereditary angioedema remains a small but closely watched therapeutic area, and companies in it generally compete on dosing frequency, efficacy and convenience for patients. Astria's long-acting approach was designed around that last point, which is part of why the program attracted a strategic buyer.