Viral disease biotech Antios Therapeutics shut down earlier this year after an FDA hold on its lead hepatitis B therapy due to a serious adverse event proved insurmountable.
Former Chief Medical Officer and co-founder Douglas Mayers, M.D., confirmed to Fierce Biotech Friday morning that the company shut down as of February.
Antios had planned to develop a curative hepatitis B therapy but progress was halted in May 2022 when the FDA placed a clinical hold over a safety report for the med, ATI-2173. The hold prompted Assembly Biosciences to terminate its clinical trial collaboration agreement as well.
The company later showcased results showing that ATI-2173 slowed rebound of the virus and allowed patients to continue treatment without having to go back on Gilead Sciences' Viread medicine during a phase 2a clinical trial. But ultimately, the FDA hold proved too difficult to overcome.
“The FDA hold was written in a way that there was no viable response,” Mayers told Fierce Biotech.
The company wound down and returned money to investors, with the doors closing officially in February.
Two other individuals formerly involved with Antios also confirmed the news, with a former scientific advisor saying that the FDA’s response to efforts to clear the hold was not favorable. The small, Atlanta-based biotech was founded in 2018 and employed between 11 and 50 people, according to its LinkedIn page.
Antios received $171 million in financing in 2021 to move ATI-2173 into the clinic. The safety event was flagged in a trial that was being conducted in Moldova when a patient experienced “a serious, unexpected, suspected adverse reaction of bradycardia and hypotension.” ATI-2173 was being combined with Assembly Biosciences' vebicorvir and a nucleotide reverse transcriptase inhibitor.
ATI-2173 was previously advanced into phase 3 study a decade ago, only to be sidelined due to cases of muscle weakness in long-term users.
Assembly also ended its quest for a functional cure of hepatitis B with vebicorvir in July 2022 after lackluster data showed the core inhibitor was unlikely to succeed. The company pivoted to earlier-stage candidates and laid off staff.
“The hepatitis B space has contracted dramatically over the past year. Hopefully, things will turn around soon,” Mayers said.
Max Bayer contributed to this article.