Bemnifosbuvir/ruzasvir is an investigational once-daily oral, pan-genotypic fixed-dose combination for chronic hepatitis C, pairing a nucleotide polymerase inhibitor (bemnifosbuvir) with an NS5A inhibitor (ruzasvir). In Phase 2, an 8-week course achieved high cure rates, with SVR12 of 98% in treatment-adherent patients and 99% in non-cirrhotic patients, although lower at 88% in those with compensated cirrhosis, alongside a favourable safety profile, no food effect and a low risk of drug-drug interactions. Two open-label Phase 3 trials, C-BEYOND (North America) and C-FORWARD (outside North America), are comparing it against sofosbuvir/velpatasvir, with topline results expected in mid-2026 and December 2026 respectively. Its potential advantages are a shorter 8-week treatment duration and efficacy across HCV genotypes 1 to 4, but because effective and relatively affordable pan-genotypic cure regimens already exist, its incremental benefit over the current standard of care is uncertain, so it remains on the watchlist. Atea’s primary patents on bemnifosbuvir, expected to expire in 2036, have been granted in 35 LMICs and are pending in another 14 LMICs. Atea owns several secondary patents on salts and polymorphs that may provide exclusivity until 2038-2042. Ruzasvir was first developed by MSD and exclusively licensed to Atea in 2021. Primary patents, expected to expire between 2031 and 2033, have been widely withdrawn and kept in force only in a few European countries. Atea filed two combination patents for bemnifosbuvir + ruzasvir. The second combination patent, expiring in 2042, is pending in 17 LMICs.