Antios Therapeutics' ATI-2173 Demonstrates Suppression of Hepatitis B Virus in Phase 1b and 2a Studies

• ATI-2173 demonstrated potent hepatitis B virus (HBV) DNA suppression
• ATI-2173, in combination with tenofovir disoproxil fumarate (TDF), was generally well-tolerated with alanine aminotransferase (ALT) normalization and no safety signals

DOYLESTOWN, Pa., March 30, 2022 /PRNewswire/ -- Antios Therapeutics, Inc. (Antios), a clinical-stage biopharmaceutical company developing innovative therapies to treat and cure chronic hepatitis B virus (HBV), today announced new data from the Phase 1b and 2a clinical trials of ATI-2173, its investigational proprietary drug candidate and the only Active Site Polymerase Inhibitor Nucleotide (ASPIN) in clinical development for HBV. These data showed that ATI-2173 alone, or in combination with tenofovir disoproxil fumarate (TDF), was generally well-tolerated among the cohorts, and ATI-2173 and TDF suppressed HBV DNA and induced declines in biomarkers of cccDNA activity. Data from these trials will be presented in two poster sessions during the 31^st Conference of the Asian Pacific Association for the Study of Liver (APASL), taking place in Seoul, South Korea on March 30, 2022 – April 3, 2022. 

Highlights from the APASL Poster Presentations

• Combining ATI-2173 with TDF, a chain-terminating nucleos(t)ide analogue, potently suppressed HBV DNA and induced declines in biomarkers of cccDNA activity.
• ATI-2173, as a monotherapy and in combination with TDF, decreased circulating HBV RNA with similar kinetics to HBV DNA.
• Patients receiving ATI-2173 and TDF combination treatment had normal alanine aminotransferase (ALT) levels or ALT levels less than 1x the upper limit of normal at the end of treatment, demonstrating the ability to administer this compound for up to 90 days.
• Many of patients receiving ATI-2173 in combination with TDF were below the limit of quantification (BLQ) at the end of treatment.
• Successful targeting of ATI-2173 to the liver greatly decreased systemic exposure to clevudine in the blood, which may lead to enhanced safety and efficacy. 
• ATI-2173 showed tolerability at 25 mg and 50 mg once-daily doses. Preliminary pharmacokinetic data analyses showed no drug-drug interaction between ATI-2173 and TDF. All subjects completed dosing without serious adverse events or adverse events leading to study drug discontinuation.

"As we continue to understand potential treatment options for the hepatitis B virus, these data are important and augment our understanding of the full potential effects of combination on/off-treatment suppression," said Nancy Reau, M.D., Professor of Internal Medicine and Hepatology Section Head at Rush Medical College. "We are seeing potential clinical benefits in combination treatment. In the Phase 2a study, no patients receiving ATI-2173 in combination with TDF had an ALT flare off-treatment and every patient completed the combination treatment for up to 90 days."

Details of the presentations are below. Both posters and oral presentations of the posters can be found on the Antios website at https://www.antiostherapeutics.com/scientific-approach/publications-presentations/. 

Title: SAVE-1: Phase 2a Results of ATI-2173, A Novel Active Site Polymerase Inhibitor Nucleotide, Combined with TDF in Chronic Hepatitis B Patients (OP-0829)
Author/Presenter: Douglas Mayers, M.D. 
Presentation Type: Scientific Debrief Session and Poster Presentation

Title: Active Site Polymerase Inhibitor Nucleotides Induce Sustained HBV RNA Suppression Following Treatment Cessation (OP-0621) 
Author/Presenter: Katherine Squires, Ph.D. 
Presentation Type: Poster Presentation

About ATI-2173

ATI-2173, Antios Therapeutics' lead once-daily, oral drug candidate for treating HBV, is an investigational phosphoramidate prodrug of clevudine monophosphate. ATI-2173 has the potential, if approved, to become the cornerstone of a curative HBV regimen. It is the only Active Site Polymerase Inhibitor Nucleotide (ASPIN) for HBV in clinical development, and its mechanism of action is designed to be complementary to other approaches that also seek to achieve a functional cure. ATI-2173 is currently in Phase 2a clinical development. The SAVE-1 (Sustained Anti-Viral Efficacy) trial is an ongoing, double-blind, randomized, placebo-controlled study of 30 patients designed to assess the safety and efficacy of 25 and 50 mg doses of ATI-2173 daily for 90 days in combination with tenofovir disoproxil fumarate (TDF), compared with TDF plus ATI-placebo (control) in chronic HBV-infected subjects, with a cohort of HDV coinfected subjects.

About HBV

Hepatitis B is a potentially life-threatening liver infection caused by HBV. HBV can cause chronic infection which leads to a higher risk of death from cirrhosis and liver cancer. Chronic HBV infection (CHB) represents a significant unmet medical need. The World Health Organization estimates that up to 300 million people worldwide suffer from chronic HBV infection, while other estimates indicate that approximately 2 million people in the United States suffer from chronic HBV infection. Approximately 900,000 people die every year from complications related to chronic HBV infection despite the availability of effective vaccines and current treatment options.

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. Its lead drug candidate ATI-2173 – the only Active Site Polymerase Inhibitor Nucleotide (ASPIN) for HBV in clinical development – has the potential, if approved, to become the cornerstone of a curative therapeutic regimen for chronic HBV. Antios is also developing a novel series of fourth-generation capsid assembly modulators (CAMs) to further expand Antios' portfolio of differentiated molecules in the HBV space. HBV is a major unmet global health problem affecting up to 300 million people worldwide, more than hepatitis C and HIV combined. For more information, please visit www.antiostherapeutics.com.  

SOURCE Antios Therapeutics