New Data on Bemnifosbuvir’s Progress in COVID-19 and HCV Trials

Atea Pharmaceuticals, Inc. announced the publication of additional data on bemnifosbuvir, a drug in development for treating COVID-19 and hepatitis C virus (HCV). It is an oral nucleotide RNA-dependent RNA polymerase (RdRp) inhibitor, currently in Phase 3 trials for COVID-19 and Phase 2 trials in combination with ruzasvir, an oral NS5A inhibitor, for HCV.¹

In March 2024, Atea Pharmaceuticals completed patient enrollment for the global phase 3 SUNRISE-3 trial evaluating bemnifosbuvir for COVID-19. The announcement highlighted the need for effective treatments for high-risk COVID-19 patients and provided an update on the trial’s progress and regulatory status.²

Study Details

JP Sommadossi, PhD founder, CEO, and chairman at Atea Pharmaceuticals discussed their two late-stage clinical programs: a direct-acting antiviral for COVID-19 and a combination therapy for Hepatitis C.

The SUNRISE-3 trial included more than 2,200 high-risk patients. Its goal was to evaluate the effect of bemnifosbuvir on patient outcomes using a range of primary and secondary endpoints. The completion of enrollment for the SUNRISE-3 trial was a key milestone in evaluating bemnifosbuvir’s potential as a treatment for high-risk COVID-19 patients.³

“For COVID-19, we have already reported clinical efficacy with good safety and tolerability,” according to Sommadossi. “The study, involved 230 patients and demonstrated a reduction in hospitalization rates of over 70%. For patients over 40 years old, this reduction was as high as 80% or more.”

The trial randomized patients to receive either bemnifosbuvir or a placebo to assess the drug’s effectiveness relative to standard treatment. Bemnifosbuvir was given according to the trial protocol, and the study encompassed supportive care and combination therapy groups.³

“Regarding hepatitis C, the situation is more straightforward. The primary endpoint here is what we call a cure, or a sustained viral response 12 weeks after the treatment duration. We’ve demonstrated up to 90% efficacy with good safety and tolerability. It’s important to note that the only two failures in the study were due to non-adherence by patients,” satted Sommadossi.

About Bemnifosbuvir

Bemnifosbuvir targets the SARS-CoV-2 RNA polymerase, showing efficacy against various COVID-19 variants, and has received Fast Track designation from the US FDA for COVID-19 treatment. In HCV treatment, bemnifosbuvir demonstrates significantly greater potency than sofosbuvir and maintains activity against resistance-associated strains.¹

According to Bruno Canard, AFMB, principal investigator in an academic lab in Marseille where the focus is on viral enzymes and their interaction with antiviral drugs, the drug’s mechanism, targeting key viral enzymes, “Bemnifosbuvir disrupts viral replication by binding to the polymerase enzyme, which is crucial for multiplying viral genomes. It has a notable feature of targeting two different sites on the same enzyme, which enhances its efficacy and helps in preventing the development of resistant viral strains.”

“Our goal is to determine how broadly this molecule can be applied to various viruses and how we can enhance its potency through additional chemical modifications and a deeper understanding of its mechanisms,” states Canard.

According to Atea and Sommadossi, the next step for the COVID-19 drug is to file a New Drug Application (NDA) in the United States. Given that the study was global, involving patients from various continents including Europe, South America, and Japan, the company will also seek regulatory approvals in these regions. For hepatitis C, the company is preparing for phase three studies. They plan to have an end-of-phase-two meeting with the FDA, EMA, and other regulatory agencies to finalize the phase three clinical program, with hopes to initiate it in early 2025.

References

1. Atea Pharmaceuticals Announces Publication of Additional Data Further Highlighting Bemnifosbuvir’s Metabolic Activation Pathway. News Release. August 28, 2024. Accessed August 28, 2024. https://ir.ateapharma.com/news-releases/news-release-details/atea-pharmaceuticals-announces-publication-additional-data

2. Atea Pharmaceuticals Completes Patient Enrollment in Global Phase 3 SUNRISE-3 Trial Evaluating Oral Antiviral Bemnifosbuvir for COVID-19 in High-Risk Patients. News Release. Published March 27, 2024. Accessed August 28, 2024. https://ir.ateapharma.com/news-releases/news-release-details/atea-pharmaceuticals-completes-patient-enrollment-global-phase-3

3. The activation cascade of the broad-spectrum antiviral bemnifosbuvir characterized at atomic resolution. PLOS BIO. August 27, 2024. Accessed August 28, 2024. https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3002743