New COVID-19 Treatment Ratutrelvir Shows Promise Against Paxlovid

Traws Pharma, Inc. (NASDAQ: TRAW) announced promising results from an interim analysis of its experimental COVID-19 treatment, ratutrelvir, which may provide a viable alternative to Paxlovid. The findings indicate that ratutrelvir potentially has fewer side effects and no instances of viral rebound reported thus far. This information comes from a mid-stage clinical trial comparing ratutrelvir and Paxlovid in patients with mild-to-moderate COVID-19.

The ongoing Phase 2 study is randomized and open-label, involving a cohort of patients ineligible for ritonavir-boosted therapies, a group often facing limited treatment options due to potential drug interactions. Ratutrelvir is designed to inhibit the SARS-CoV-2 main protease independently, without the need for ritonavir.

In the interim analysis, data from 37 patients were evaluated, consisting of 25 individuals treated with ratutrelvir and 12 treated with Paxlovid. The trial has surpassed half of its planned enrollment of 90 patients. Patients receiving ratutrelvir took the medication once daily for 10 days, whereas those in the Paxlovid group followed the standard regimen of five days.

According to Traws Pharma, patient-reported symptom outcomes were numerically comparable between the two treatment groups, based on standardized symptom diaries. The analysis was descriptive, with no formal statistical tests performed. Importantly, no symptom or virologic rebound events were recorded among the ratutrelvir recipients, while one rebound event—representing 8.3 percent—occurred in the Paxlovid group. This viral rebound has been a significant concern among healthcare professionals and patients using current oral antiviral therapies.

The interim data also highlighted a more favorable tolerability profile for ratutrelvir. Mild dyspepsia was reported as the most common adverse event, affecting two patients. Notably, no treatment discontinuations were observed, and adverse effects typically associated with Paxlovid, such as taste disturbance and dizziness, were absent in the ratutrelvir group.

Some patients in the ratutrelvir cohort were ineligible for Paxlovid due to contraindications or risks of drug interactions. Their symptom improvement mirrored that of the wider ratutrelvir group, suggesting potential benefits for patients frequently excluded from antiviral treatments.

Traws Pharma executives stated that the absence of viral rebound, combined with the extended dosing schedule and improved tolerability, supports the need for further studies on ratutrelvir. This could include its role not only in treating acute COVID-19 but also in potentially mitigating the risk of long COVID.

Final results from the study are expected to be released in January 2026. Enrollment and follow-up are currently ongoing, with the company emphasizing that larger datasets will be necessary to establish definitive conclusions regarding efficacy and long-term outcomes.