Antios Therapeutics, a biotech company focused on viral diseases, ceased its operations earlier this year following an FDA-imposed hold on its lead hepatitis B therapy due to a serious adverse event that proved insurmountable. Former Chief Medical Officer and co-founder, Douglas Mayers, M.D., confirmed the company’s closure in February.
Antios had ambitious plans to develop a curative therapy for hepatitis B but faced a setback in May 2022 when the FDA issued a clinical hold in response to a safety report concerning its medication, ATI-2173. This development led to the termination of the clinical trial collaboration agreement with Assembly Biosciences, a former partner.
Subsequently, Antios presented data demonstrating that ATI-2173 had the potential to slow the resurgence of the hepatitis B virus, allowing patients to continue treatment without needing Gilead Sciences’ Viread medication during a phase 2a clinical trial. However, the FDA’s stringent hold made it exceedingly challenging to proceed. According to Mayers, “The FDA hold was written in a way that there was no viable response.”
The company decided to wind down its operations and return funds to investors, officially closing its doors in February.
Additional individuals previously associated with Antios corroborated the news, with a former scientific advisor noting that the FDA’s response to efforts to resolve the hold was unfavorable. Antios, a small biotech firm based in Atlanta, was founded in 2018 and employed between 11 and 50 people, according to its LinkedIn page.
In 2021, Antios secured $171 million in financing to advance ATI-2173 into clinical trials. The safety concern arose during a trial conducted in Moldova when a patient experienced a severe, unexpected, suspected adverse reaction involving bradycardia and hypotension. ATI-2173 had previously advanced to a phase 3 study a decade ago but was sidelined due to cases of muscle weakness in long-term users.
Assembly Biosciences also abandoned its pursuit of a functional hepatitis B cure with vebicorvir in July 2022 after lackluster data suggested that the core inhibitor was unlikely to succeed. The company shifted its focus to earlier-stage candidates and implemented staff layoffs.
“The hepatitis B space has contracted dramatically over the past year. Hopefully, things will turn around soon,” Mayers remarked, reflecting on the challenges faced in this therapeutic area.