Traws Pharma Reports Final Phase 2a Results for Ratutrelvir: Symptom Resolution in 13.5 Days vs 14.5, No Viral Rebound Through Day 28
Traws Pharma, Inc. (Nasdaq: TRAW), a clinical-stage biopharmaceutical company based in Newtown, Pennsylvania, on November 12 announced the final results of its Phase 2a study of ratutrelvir, an investigational once-daily, ritonavir-free oral antiviral for COVID-19. In patients eligible to receive Pfizer's PAXLOVID, the median time to sustained symptom resolution was 13.5 days with ratutrelvir versus 14.5 days with PAXLOVID, with no viral rebound observed through Day 28.
The randomized, active-controlled study enrolled 92 subjects with mild-to-moderate COVID-19. Among 62 PAXLOVID-eligible subjects, ratutrelvir 600 mg once daily for 10 days was compared with PAXLOVID for 5 days; viral RNA declined at a similar rate in both arms, and treatment-related adverse events were reported in 1 of 32 ratutrelvir patients and 4 of 30 PAXLOVID patients. A separate cohort of 30 PAXLOVID-ineligible subjects, who were older and carried a high burden of cardiovascular and pulmonary comorbidities, saw symptoms resolve in 14.0 days on ratutrelvir, with no treatment-related adverse events reported.
Robert R. Redfield, MD, Chief Medical Officer of Traws Pharma, said the final results support the potential of ratutrelvir as a once-daily, ritonavir-free treatment option, including for patients who cannot take ritonavir-boosted therapy because of their other medications, and that its tolerability profile and the absence of viral rebound encourage further clinical evaluation. The company said ratutrelvir has shown in vitro activity against all 12 SARS-CoV-2 strains tested to date and acts on the viral main protease Mpro, an enzyme highly conserved across variants.
Traws intends to discuss a registration strategy with the U.S. Food and Drug Administration (FDA) focused on adults at high risk of progression to severe COVID-19 who are ineligible for PAXLOVID, including a potential adaptive Phase 2b or pivotal program and Fast Track designation. Ratutrelvir has not been approved by any regulatory authority.
The company also announced completion of a bridging study of a compressed tablet formulation of tivoxavir marboxil (TXM), its investigational once-monthly antiviral for seasonal and pandemic influenza prophylaxis. The tablet provided comparable exposure to the powder-in-capsule form and was well tolerated. In a toxicology retest, two independent rat Pig-a gene mutation studies showed no mutagenic effect at doses up to 500 mg/kg, a margin of about 125-fold over the planned clinical exposure, and the company expects to resubmit the updated package to regulators in the fourth quarter of 2026. (Source: Traws Pharma)
Source: Traws Pharma
Published by GSM · USA (original Chinese edition)
Photo: 图：新冠病毒 SARS-CoV-2 示意图。CDC 的 Alissa Eckert 与 Dan Higgins 制，Wikimedia Commons，公共领域。 / Image: Illustration of the SARS-CoV-2 virus. By Alissa Eckert and Dan Higgins, CDC, via Wikimedia Commons, public domain.
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