공시 • Oct 21
Enanta Pharmaceuticals, Inc. Presents New Data for Zelicapavir, its N-Protein Inhibitor and EDP-323, L-Protein Inhibitor
Enanta Pharmaceuticals, Inc. announced that new data for zelicapavir, its oral, once-daily, N-protein inhibitor, and EDP-323, its oral, once- daily, N-protein inhibitor, both in development for the treatment of respiratory syncytial virus (RSV), will be presented at IDWeek™? 2025 being held October 19 - 22, 2025, virtually and in Atlanta, Georgia. A post hoc analysis of a Phase 2 study of zelicapavir in children 28 days to 36 months reported in December 2024, demonstrated that treatment with zelicapavir resulted in a shorter time to complete resolution of RSV-related symptoms, as measured by ReSViNET, a parent/guardian clinical scoring system. The randomized, double-blind, placebo-controlled trial was conducted in children 28 days to 36 months of age evaluating the safety, pharmacokinetics, and antiviral activity of zelicapavir given once daily for 5 days. Caregivers reported the severity of RSV-related symptoms daily from baseline through Day 14. In the study, 96 patients were randomized and dosed (n=69 zelicapavir, n=27 placebo). Although resolution of symptom severity to mild showed no difference, a post hoc analysis of time to complete resolution of symptoms (defined as absent and discharged from hospital), showed an estimated Kaplan-Meier median of 6.99 days for zelicapavir versus 8.60 days for placebo. Similarly, an analysis of sustained resolution (defined as absent and remaining absent at all subsequent time points and discharged from hospital) resulted in 6.99 days for zelicapavir versus 10.68 days for placebo. All zelicapavir recipients achieved model-predicted target drug exposures. Adverse events (AEs) were similar between treatment groups, with none leading to treatment discontinuation or study withdrawal. These data demonstrate that treatment with zelicapavir is associated with a shorter time to complete resolution of RSV symptoms in children, thereby supporting further evaluation of zelicapavir in pediatric clinical trials. A randomized, double-blind, placebo-controlled human viral challenge Phase 2a study evaluated the efficacy, antiviral activity, safety and pharmacokinetics of EDP-323. Healthy volunteers were inoculated with RSV-A on Day 0. After confirmed RSV infection or 5 days later, randomized participants received EDP-323 600mg (n=47), 200mg (with 600mg loading dose, n=47), or placebo (n=47) once daily for 5 days and were followed through 28 days. Clinical symptoms were assessed once-daily using the Respiratory Infection Intensity and Impact Questionnaire (RiiQ™) and viral loads were assessed by quantitative real-time PCR on nasal washes. Participants showed rapid (within the first 24 hours) and statistically significant improvements in RiiQ™ RSV symptoms and viral load after EDP-323 dosing. Compared to placebo, there were 73% (p=0.0012), 61% (p=0.0010), and 67% (p<0.0001) RiiQ™ total symptom score AUC reductions in the 200mg, 600mg, and EDP-323 pooled recipients, respectively. Lower respiratory tract disease scores AUC were reduced by 95% (p=0.0002), 73% (p=0.0088), and 85% (p=0.0002) respectively, in the 200mg, 600mg, and pooled EDP-323 recipients versus placebo. There were 87% and 85% viral load AUC reductions in 200mg and 600mg recipients, respectively versus placebo (all p<0.0001). EDP-323 dosing groups showed similar efficacies. Frequencies of treatment-emergent adverse events (TEAEs) were similar across EDP-323 and placebo groups. No serious TEAEs, severe AEs, or AEs leading to treatment discontinuation or study withdrawal occurred. These findings support the further development of EDP-323 as a once-daily, oral RSV treatment. A randomized, double-blind, placebo-controlled, human viral challenge Phase 2a study evaluated the efficacy, antiviral activity, safety and pharmacokinetics of EDP-323. Healthy volunteers were inoculated with RSV-A on Day 0. RSV real-time PCR was performed, and nasal washes were collected twice daily on Days 2-12. Study participants were randomized 1:1:1 and received either 600mg of EDP-323 orally for 5 days (high-dose group), 600mg loading dose for 1 day followed by 200mg once daily for 4 days (low-dose group), or placebo. A post exposure prophylaxis (PEP) analysis was performed in subjects who were not infected by Day 5 after RSV exposure. In this population, 68 RSV-exposed, susceptible subjects were randomized to receive EDP-323 (low dose n=24, high dose n=21) or placebo (n=23). Of these subjects, 26% (6/23) of those who received placebo became infected versus 0% (0/45) of EDP-323 recipients (p<0.001). Evaluated separately, the two EDP-323 dosing groups’ PEP effects were statistically significant (low dose p=0.009, high dose p=0.022) versus placebo. There were no serious TEAEs, severe AEs, or AEs leading to treatment discontinuation or study withdrawal occurred. The frequency of TEAEs were similar across EDP-323 and placebo groups. These data suggest that EDP-323 is highly effective in preventing RSV infection when initiated up to 5 days after RSV exposure and further support evaluating the drug for prophylaxis.