and ruzasvir,” continued Dr. Sommadossi. “The progress we are making today sets the stage for a number of important milestones over the next 18 months. Importantly, we remain well capitalized to advance the clinical development of these product candidates in our effort to provide new medicines to patients with severe viral diseases.”
Bemnifosbuvir (AT-527) Program Update for COVID-19
New Topline Efficacy Results from MORNINGSKY Trial: In a topline analysis of data from the MORNINGSKY trial, the primary endpoint, time to symptom alleviation, was not achieved. However, a 71% reduction in hospitalization (2.9% versus 10%) was observed (p=0.047, unadjusted, exploratory) in the bemnifosbuvir arm (n=137) versus placebo (n=70). There were no deaths in the trial. Hospitalization and death are study endpoints that are currently preferred by the U.S. Food and Drug Administration and other regulatory authorities.
The study enrolled a broad patient population of whom approximately 50% were high risk and 50% were standard risk; 28% of patients were vaccinated; and 56% were seropositive at baseline. Consistent with previous studies, bemnifosbuvir 550 mg twice-daily (BID) was generally safe and well tolerated. There were no drug-related serious adverse events. Adverse events leading to treatment discontinuation were 3% for bemnifosbuvir versus 7% for placebo and there were no gastrointestinal-related events leading to treatment discontinuation.
MORNINGSKY was a randomized, double-blind, multi-center, placebo-controlled Phase 3 trial evaluating the efficacy, safety, antiviral activity, and pharmacokinetics of bemnifosbuvir in up to 1,400 patients randomized 2:1 to receive bemnifosbuvir 550 mg BID or placebo in an outpatient setting. As previously announced, the study was closed out early in December 2021, having enrolled 216 patients of which 207 were evaluable for efficacy. Atea plans to present the full results of this study at an upcoming scientific meeting.
New Data from Final Analysis of Phase 2 Hospitalized Study in High-Risk Patients: Final clinical results from the Phase 2 hospitalized study in high-risk patients (n=83) suggest potential clinical benefits. The overall rate of disease progression was low, which had an impact on the ability to assess the primary endpoint of progression of respiratory insufficiency (PRI) rate. The results showed a 7.5% PRI rate for bemnifosbuvir 550 mg BID versus a 10% PRI rate for placebo (primary endpoint). The respiratory events associated with progression were less severe in the bemnifosbuvir treated patients as compared to those receiving placebo. There were 3 deaths in the study, no deaths were reported in patients treated with bemnifosbuvir versus 3 deaths reported with placebo.
Final virology results (secondary endpoint) were consistent with previously reported interim data from this study. Bemnifosbuvir was generally safe and well tolerated with no drug related serious adverse events and no adverse events leading to treatment discontinuation.
The global Phase 2 trial was a randomized, double-blind, placebo-controlled, multi-center study to evaluate bemnifosbuvir in patients with moderate COVID-19 in the hospital setting. The key inclusion criteria for this study were adult patients 18 years or older with risk factors such as obesity, diabetes, asthma and hypertension. Study objectives were to assess safety, tolerability, clinical and antiviral efficacy. Patients were randomized within five days of symptom onset to receive either bemnifosbuvir (550 mg BID in Part A; 1100 mg BID in Part B) or placebo for five days. In total, 81 patients were randomized in Part A (41 patients in the 550 mg BID arm; 40 patients in placebo arm) and 2 patients were randomized in Part B (0 patients in 1100 mg BID arm; 2 patients in placebo arm). The evolving nature of the standard of care resulted in the early close out of the study which limited the Part B enrollment. Atea plans to present the full results of this study at an upcoming scientific meeting.
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