Top-line Phase 2 trial data for hepatitis C combo therapy expected soon
Results from Phase 3 study testing same treatment due by end of 2026
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A large clinical trial evaluating Atea Pharmaceuticals’ fixed-dose oral combination of bemnifosbuvir and ruzasvir in adults with chronic hepatitis C remains on track, with top-line results expected in mid-2026.
Dubbed C-BEYOND (NCT06868264), the North American study has enrolled more than 880 adults with chronic hepatitis C virus (HCV) infection who have not previously received standard antiviral treatment. Participant dosing started last year.
The trial is running in parallel with the global Phase 3 C-FORWARD trial (NCT07037277), which is testing the combination therapy in the same patient population but outside North America. Enrollment in this trial, ongoing in more than 100 sites in Europe, Asia, and Africa, is expected to wrap up midyear, with top-line data anticipated by year’s end.
Both trials are comparing the bemnifosbuvir/ruzasvir combination with Epclusa (sofosbuvir/velpatasvir), an approved therapy for hepatitis C.
“With two pivotal Phase 3 readouts for our HCV program on the horizon, 2026 will be a catalyst-rich year for Atea,” Jean-Pierre Sommadossi, PhD, Atea’s CEO and founder, said in a company press release. “By simplifying HCV treatment for both patients and providers, our regimen preferentially aligns with the expanding ‘test-and-treat’ model of care, which we believe will result in more patients treated and an opportunity to accelerate HCV elimination efforts.”
The “test-and-treat” model of care enables rapid hepatitis C diagnosis and treatment initiation at the point of care.
Drug combo aims to block HCV replication in liver cells
The HCV, spread via contact with infected blood or other bodily fluids, causes inflammation of the liver. If left untreated, it can lead to liver damage, irreversible scarring (cirrhosis), liver failure, and cancer. An estimated 50 million people worldwide are chronically infected with HCV, and as many as four million of those are in the U.S.
Taken once daily as tablets, the bemnifosbuvir/ruzasvir combination is designed to block HCV replication in liver cells. While it works similarly to existing antiviral treatments for hepatitis C, Atea believes the combo has the potential to clear the virus from the body more quickly and be more convenient for patients.
A previous Phase 2 trial (NCT05904470) tested the combination therapy in patients with chronic hepatitis C for 8 weeks. Data showed that 98% of treatment-adherent participants achieved 12-week sustained virologic responses (SVR12), defined as reaching an HCV level below the lower limit of quantification 12 weeks (three months) after treatment completion.
SVR12 is generally considered a functional cure for HCV, meaning the infection has been contained to the point that the body’s natural immune defenses can handle it without the need for treatment.
The data generated to date for the regimen of bemnifosbuvir and ruzasvir support a differentiated, potentially best-in-class profile, combining high efficacy, short treatment duration with low risk of drug-drug interactions, and dosing convenience.
Additional studies have shown the combo can be taken with or without food and does not require dose adjustments for those with liver or kidney problems. In addition, it has a low risk of drug-drug interactions, meaning it’s unlikely to interfere with other medications. Atea notes that this is particularly relevant, as its market research indicates that up to 80% of HCV-infected patients take at least one additional medication.
“The data generated to date for the regimen of bemnifosbuvir and ruzasvir support a differentiated, potentially best-in-class profile, combining high efficacy, short treatment duration with low risk of drug-drug interactions, and dosing convenience,” Sommadossi said.
In C-FORWARD and C-BEYOND, participants are randomly assigned to receive either bemnifosbuvir/ruzasvir or Epclusa once daily. Those without cirrhosis will receive about two months of the combination, while those with compensated cirrhosis (irreversible scarring in a still-working liver) will be treated for about three months. Participants assigned Epclusa will receive about three months of treatment, regardless of cirrhosis status.
The studies’ primary goal is to assess the proportion of participants with undetectable HCV in the blood after about six months, which also captures SVR12.
Atea chooses lead hepatitis E virus treatment candidate
Atea is also developing potential treatments for hepatitis E virus (HEV) infection, for which no therapies are currently approved. In most cases, the viral infection resolves on its own. Still, it can cause chronic hepatitis in certain groups, including pregnant women and immunocompromised patients, such as organ transplant recipients.
“HEV represents a critical gap in care with no approved therapies, leaving vulnerable populations, including transplant recipients and other immunocompromised patients, at risk for rapid disease progression,” Sommadossi said.
In March, Atea presented preclinical data showing that two of its drug candidates, AT-587 and AT-2490, were 30 to 150 times more potent against HEV than antiviral therapies used off-label for hepatitis E, including sofosbuvir (sold as Sovaldi) or ribavirin (sold as Virazole, with generics available). The compounds were also active against a range of other viruses, including HCV.
Atea has selected AT-587 as its lead candidate and plans to move it to Phase 1 clinical trial testing, the first stage of human testing, by midyear.
“In parallel, our HEV program underscores our continued commitment to developing antiviral therapeutics for serious viral diseases where significant unmet needs persist,” Sommadossi said. “Following encouraging preclinical data, we look forward to advancing our potential first-in-class candidate, AT-587, into the clinic.”
