The combined business entity with Boundless Bio, which will carry Serapha Bio’s name and fold in Boundless Bio, will focus on the development of a gene editor for alpha-1 antitrypsin deficiency.
Private biotech Serapha Bio is soaring onto the public markets through a reverse merger with California’s Boundless Bio, bringing with it $230 million in starting funds and a gene editing asset developed in China.
Serapha’s $230 million haul consists of a $138 million placement that had already been funded in a prior series A round, buffed up by $92 million in pre-closing private investments, which the biotech expects to close concurrently with the merger, according to a Tuesday news release. The companies expect to complete their business combination in the fourth quarter, after which Serapha will carry the ticker symbol AATD.
The resulting entity will largely belong to Serapha’s pre-merger stockholders, who will own around 96.3% of the combined company, while Boundless shareholders will own the remaining 3.7%. The boards of directors of Serapha and Boundless have unanimously approved and endorsed the merger.
Concurrently with the combination, Serapha entered into a licensing deal with Shanghai-based YolTech Therapeutics, handing over an undisclosed upfront sum and a minority equity stake in Serapha. In return, the California biotech will gain worldwide license to develop and commercialize the investigational gene editor SERP-01 outside Greater China.
SERP-01, designed to correct a mutation to the SERPINA1 gene, will be the main focus of the post-merger entity, according to the Tuesday announcement. Serapha will advance SERP-01 for severe alpha-1 antitrypsin deficiency (AATD). The disease is a hereditary condition that arises from a mutation in SERPINA1, which produces misfolded proteins that, in turn, result in disease-causing clumps across different organs.
Patients with AATD suffer from various symptoms linked to lung and liver dysfunction, such as shortness of breath, chronic coughs, respiratory infections, fatigue and swelling. Around 1 in 3,500 people in the U.S. have AATD.
Several biopharma players, including Beam Therapeutics and Wave Life Sciences, have been taking a gene editing approach to the disease.
The companies released respective readouts last month. Beam’s DNA editor BEAM-302 cut circulating levels of mutant AAT by approximately 80%, while also boosting production of the healthy protein. Wave, meanwhile, is advancing an RNA editor called WVE-006, a single dose of which decreased levels of the toxic protein by up to 59.1%. This effect improved to 70.5% for multiple doses.
Also playing in the editor arena is Regeneron, which late last year paid $150 million upfront—and earmarked up to $125 million in near- and mid-term milestones—to partner with Tessera Therapeutics and advance an in vivo gene editing therapy for AATD.
