New Data from Enanta’s Phase 2a Human Challenge Study of EDP-938 for RSV Demonstrates Highly Statistically Significant Reductions (p<0.001) in Total Symptom Score, Mucus Weight and RSV Viral Load as Measured by RT-PCR Assay and by Plaque Assay

Enanta Pharmaceuticals, Inc. (NASDAQ:ENTA), a research and development-focused biotechnology company dedicated to creating small molecule drugs for viral infections and liver diseases, today announced that new data from its Phase 2a Human Challenge Study of EDP-938 is being presented as a late-breaker oral presentation today at IDWeek 2019 in Washington, D.C. EDP-938 is Enanta’s lead N-protein inhibitor being developed for the treatment of RSV infection.

Today’s late-breaking oral presentation will include data demonstrating that in the RSV Challenge study EDP-938 administered once or twice daily achieved highly statistically significant reductions (p<0.001) in RSV viral load by quantitative viral culture (plaque assay), as well as in mucus production. These data were consistent with the data for the primary efficacy endpoint of RSV viral load reduction by RT-PCR, as well as the secondary endpoint of reduction in RSV-associated total symptom score, both of which endpoints have been reported previously.

The results of the RSV quantitative viral culture assay (Log₁₀ plaque forming units/mL) demonstrated highly statistically significant (p<0.001) reductions in RSV viral load area under the curve (AUC) of 82.53% and 77.43%, in the QD and BID arms, respectively, compared to the placebo arm and without a significant difference between the dosing groups. These findings confirm the previously reported, highly statistically significant (p<0.001) reductions in RSV viral load AUC by quantitative RT-PCR in the QD and BID arms of 74.43% and 71.46%, respectively, compared to placebo and without a significant difference between the dosing groups. Additionally, highly statistically significant reductions (p<0.001) in RSV-associated nasal mucus production (mucus weight) of 72.06% and 77.67% in the QD and BID arms, respectively, compared to placebo and without a significant difference between the dosing groups.

These data support the further clinical evaluation of EDP-938. Enanta plans to initiate a Phase 2b clinical study of EDP-938 in adult out-patients with RSV by the end of 2019.

The double-blind, placebo-controlled, Phase 2a study being presented evaluated EDP-938 in adult volunteers inoculated with RSV-A Memphis 37b. EDP-938 was dosed for 5 days as 600mg once daily (QD arm) or a 500mg loading dose then 300mg twice daily (BID arm), or study subjects received placebo. A total of 115 subjects were randomized and inoculated; 86 were included in the analysis of the intent-to-treat-infected (ITT-I) population, which comprised all randomized and inoculated subjects who received at least one dose of study drug and who had confirmed RSV infection.