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Antios Therapeutics Doses First Patients in SAVE 1, a Phase 2a Study of ATI-2173 in Patients with Chronic Hepatitis B Virus (HBV)

SAVE 1 to evaluate ATI-2173 in combination with tenofovir (TDF) vs. TDF plus placebo
SAVE 1 to include cohort of Hepatitis Delta Virus (HDV) co-infected subjects to assess ATI-2173 activity against HDV

MENDHAM, N.J., April 21, 2021 (GLOBE NEWSWIRE) – Antios Therapeutics, Inc. (“Antios”) today announced that it has dosed the first patients in its Sustained Anti-Viral Efficacy (SAVE) clinical trial, a Phase 2a study of ATI-2173, an Active Site Polymerase Inhibitor Nucleotide (ASPIN) in clinical development as a backbone of a potentially curative regimen for chronic HBV.

The double-blind randomized controlled trial plans to enroll 30 patients and will assess the safety and efficacy of 25mg and 50mg doses of ATI-2173 in combination with tenofovir (TDF) compared with TDF plus ATI-placebo (control) in chronic HBV-infected subjects. A third cohort will evaluate 50mg of ATI-2173 and TDF against the control arm in HBV/HDV co-infected subjects. Efficacy will be assessed by both on-treatment maximum HBV DNA level responses and by off-treatment sustained virologic responses (SVR)s for the treatment arms in HBV-mono-infected subjects and by HDV RNA treatment responses in the HBV/HDV-coinfected subjects.

Following a screening period of up to eight weeks, subjects will be randomized to receive either once-daily, oral ATI-2173 plus TDF arm or control for 12 weeks, after which they will be evaluated off therapy during a 24-week follow-up period. Subjects’ HBV DNA will be measured regularly during both the treatment and follow-up periods. Subjects whose HBV DNA remains undetectable at six months post-treatment will be followed for up to an additional 18 months. Additional details of the clinical trial are available on clinicaltrials.gov (NCT04847440).

“We saw evidence of durable on- and off-treatment viral suppression in the Phase 1b study where ATI-2173 monotherapy was given for only 28 days,” said Gregory Mayes, chief executive officer of Antios. “We believe that the unique ability of ATI-2173 to inhibit all stages of HBV DNA synthesis could generate additional SVRs following three months of finite treatment in combination with the standard of care, TDF, potentially turning HBV from a chronic disease to a curable one for some patients.”

Douglas Mayers, chief medical officer of Antios added, “In addition to determining the ability of ATI-2173 to generate increased levels of SVR, this will be an extremely important study, as it may also provide proof-of-concept for the drug to be used as a treatment for HDV. Preclinical work in woodchuck models of HBV/HDV coinfection has demonstrated the ability of ATI-2173’s active metabolite to significantly reduce HDV RNA levels. This would be a tremendously promising finding if replicated in humans, as effective treatment of HDV remains a high unmet need. We anticipate completing dosing for SAVE 1 before the end of 2021 and presenting the results at a future scientific conference.”

About ATI-2173

ATI-2173 is a novel, orally administered, liver-targeted Active Site Polymerase Inhibitor Nucleotide (ASPIN) molecule designed to deliver the 5’-monophosphate of clevudine to the liver where it is metabolized to the active 5’-triphosphate. This L-nucleoside’s active 5’-triphosphate has unique antiviral properties as a non-competitive, non-chain terminating HBV polymerase inhibitor that distorts the active site of HBV polymerase resulting in potent HBV antiviral activity and extended off-treatment suppression of HBV DNA. ATI-2173 targets the liver, delivering high levels of the unique 5’- triphosphate while limiting systemic exposure to the parent L-nucleoside. ATI-2173 has the potential to become an integral part of a curative combination regimen for chronic hepatitis B.

About Antios Therapeutics Inc.

Antios Therapeutics is a clinical-stage biopharmaceutical company focused on the development of innovative therapies to treat and cure viral diseases. Antios is currently developing ATI-2173, aiming to provide chronic hepatitis B infected patients with a curative combination regimen.