Enanta's EDP-938 misses goal of Phase IIb trial in RSV

US clinical-stage biotech Enanta Pharmaceuticals (Nasdaq: ENTA) saw its shares tumble yesterday, and fall 16% to $38.49 pre-market today, after it reported disappointing top-line results for RSVP, its Phase IIb study evaluating EDP-938, a potent N-protein inhibitor, in otherwise healthy adults with community-acquired respiratory syncytial virus (RSV).

In this low-risk patient population which had mild, self-resolving upper respiratory tract infection, EDP-938 did not meet the primary endpoint of reduction in total symptom score compared to placebo, or the secondary antiviral endpoints. However, a statistically-significant difference in the number of subjects achieving undetectable RSV RNA at the end of treatment at Day 5 was observed with EDP-938 compared to placebo (p=0.033). Further, EDP-938 demonstrated a favorable safety profile, consistent with that observed in approximately 500 subjects exposed to date.

Enanta continues to evaluate EDP-938 in high-risk populations in ongoing and planned clinical studies, including pediatric patients, adult hematopoietic cell transplant recipients, and a high-risk adult population, all of which have the most significant unmet need.