Traws Pharma, Inc. (NASDAQ: TRAW) has announced promising interim results from a mid-stage clinical trial of its experimental COVID-19 treatment, ratutrelvir. The findings suggest that ratutrelvir may provide a viable alternative to Paxlovid, with fewer side effects and no observed viral rebound in patients to date. This data comes from a pre-specified interim analysis of an ongoing Phase 2, randomized, open-label study that compares ratutrelvir with Paxlovid in patients suffering from mild-to-moderate COVID-19.
The trial includes a distinct cohort of patients who are ineligible for ritonavir-boosted therapies. This group often faces limited treatment options due to potential drug interactions or contraindications. Ratutrelvir functions as an oral antiviral that targets the SARS-CoV-2 main protease without requiring ritonavir for boosting.
In the interim analysis, researchers evaluated data from 37 participants, comprising 25 treated with ratutrelvir and 12 receiving Paxlovid. Enrollment has surpassed half of the planned total of 90 participants. Patients taking ratutrelvir were administered the drug once daily for ten days, while the Paxlovid group followed the standard five-day regimen.
According to Traws Pharma, patient-reported symptom outcomes were comparable between the two groups, based on standardized symptom diaries. Notably, the analysis was descriptive, lacking formal statistical testing. Importantly, no symptom or virologic rebound events were reported among patients treated with ratutrelvir. In contrast, one rebound event occurred in the Paxlovid group, affecting 8.3 percent of that cohort. The issue of viral rebound has raised concerns among clinicians and patients using existing oral antiviral treatments.
Safety Profile and Patient Eligibility
The interim data underscored a more favorable tolerability profile for ratutrelvir. The most commonly reported adverse event was mild dyspepsia, occurring in two patients. The study reported no treatment discontinuations, and adverse effects often associated with Paxlovid—such as taste disturbance and dizziness—were absent in the ratutrelvir group.
Among the ratutrelvir participants, six individuals were deemed ineligible for Paxlovid due to contraindications or risks of drug-drug interactions. These patients exhibited symptom improvement patterns similar to the broader ratutrelvir-treated population, indicating potential utility in a demographic frequently excluded from antiviral therapies.
According to Traws Pharma executives, the lack of viral rebound, combined with extended dosing and improved tolerability, warrants further investigation of ratutrelvir. The company is particularly interested in exploring its potential role in addressing both acute COVID-19 and the risk of long COVID.
Final data from the study are anticipated to be released in January 2026. Traws Pharma has confirmed that enrollment and follow-up are ongoing, emphasizing that larger datasets will be necessary to draw definitive conclusions about the drug’s efficacy and long-term outcomes.
