Serapha Bio announced on June 24 a reverse merger with California-based Boundless Bio, positioning the private biotech to enter the public markets with $230 million in starting funds and a gene editing asset developed in China.
The $230 million includes a previously funded $138 million Series A placement, supplemented by $92 million in pre-closing private investments that Serapha expects to close concurrently with the merger. According to a Tuesday news release, the companies anticipate completing their business combination in the fourth quarter. The merged entity will trade under the ticker symbol AATD.
Following completion of the deal, Serapha’s pre-merger stockholders are expected to own approximately 96.3% of the combined company, while Boundless shareholders will hold about 3.7%. Both companies’ boards of directors have unanimously approved and endorsed the transaction.
Alongside the merger, Serapha has entered into a licensing agreement with Shanghai-based YolTech Therapeutics. Under this arrangement, Serapha is providing an undisclosed upfront payment and a minority equity stake in exchange for worldwide rights—excluding Greater China—to develop and commercialize SERP-01, an investigational gene editor designed to correct mutations in the SERPINA1 gene.
SERP-01 will be advanced as a treatment for severe alpha-1 antitrypsin deficiency (AATD), which is caused by mutations that lead to misfolded proteins accumulating across different organs. Patients typically experience symptoms such as shortness of breath, chronic coughs, respiratory infections, fatigue, and swelling; around one in 3,500 people in the United States have AATD.
Other biopharmaceutical companies are also pursuing gene editing approaches for AATD. Beam Therapeutics recently reported that its DNA editor BEAM-302 reduced circulating levels of mutant AAT by about 80% while increasing healthy protein production. Wave Life Sciences is developing WVE-006—an RNA editor—which achieved up to 70.5% reduction of toxic protein after multiple doses. Regeneron has also entered this space through an agreement last year involving Tessera Therapeutics.
