Abpro is taking a second run at the public markets. Five years after pulling out of a planned IPO, the antibody specialist is back with a special purpose acquisition company, agreeing to combine with Atlantic Coastal Acquisition Corp. II to secure a Nasdaq listing and cash for a pipeline dominated by preclinical immuno-oncology programs.
The press release gives Abpro an implied equity valuation of $725 million but makes no mention of how much the transaction will add to the biotech’s bank balance. Atlantic Coastal put $306 million in a trust account after it closed its IPO early last year but redemptions later decimated its holdings. In April, stockholders redeemed shares worth $276 million, leaving $36 million in the account at the end of June.
Abpro will use whatever proceeds it receives to fund a pipeline that is, with the notable exception of the addition of a midphase COVID-19 program, very similar to the set of candidates that were in development at the time of the failed IPO attempt in 2018.
Back then, Abpro listed a HER2xCD3 T-cell engager, ABP-100, as its lead program. The candidate was in IND-enabling studies then and seems to still be there now, according to Abpro’s website, but is nearing phase 1. Abpro had two other candidates at the IND-enabling stage at the time of its IPO filing. One asset, a ligand trap for eye diseases, is still at the same stage; the other is no longer part of the pipeline.\
Additions to the immuno-oncology pipeline include a candidate that targets CD3 and Claudin18.2, one of the hottest targets in cancer, and another HER2xCD3 bispecific that landed Abpro a deal with Celltrion. The Korean biotech invested in Abpro and offered up to $1.75 billion in milestones for the global rights.
The most advanced addition to the pipeline is a SARS-CoV-2 antibody, an approach that made waves early in the pandemic but was later nullified by the rise of new variants. Abpro began a phase 2/3 clinical trial of its lead COVID-19 candidate, ABP-300, late in 2020. One year later, the biotech touted the effect of its follow-up candidate, ABP-310, against omicron and targeted emergency use authorization in 2022.
Updates on the COVID-19 program dried up after the omicron statement. Abpro has filed to raise money twice in recent years, offering $40 million in 2020 and $80 million in 2022. At the time of the filings, the biotech had sold $18 million in the first offering and $2 million in the second offering.