RSV Vaccine Candidate Publishes Positive Phase 2 Challenge Results

Massachusetts-based Enanta Pharmaceuticals, Inc. today announced that data from its Phase 2 human challenge study of EDP-938 had been published in The New England Journal of Medicine (NEJM).

EDP-938 is Enanta’s lead N-protein inhibitor, being developed to treat Respiratory Syncytial Virus (RSV) infection.

The NEJM publication highlighted results from the Phase 2 human challenge study.

The primary efficacy endpoint was met with a highly statistically significant reduction (p<0.001) in viral load AUC was observed for each of the EDP-938 dosing groups as compared with placebo.

EDP-938 lowered viral load AUC to 203.95 ± 173.50 hours x Log10 copies/mL in the QD arm and 217.71 ± 217.55 hours x Log10 copies/mL in the BID arm, compared to 790.15 ± 408.80 hours x Log10 copies/mL in the placebo arm (p<0.001 for each of the EDP-938 groups compared to placebo).

And there was no statistically significant difference between the two EDP-938 dosing groups.

For the key secondary efficacy endpoint, a highly statistically significant reduction was observed in total symptom score for each of the EDP-938 dosing groups (124.47 hours x score ± 115.60 for the QD arm and 181.75 ± 248.42 hours x score for the BID arm, compared to 478.75 ± 422.29 hours x score in the placebo arm (p<0.001 for each of the EDP-938 groups compared to placebo).

EDP-938 demonstrated good pharmacokinetics, and mean trough levels of the drug were maintained at approximately 20-40x above the in vitro EC90 for RSV-infected human cells.

Overall, EDP-938 demonstrated a favorable safety profile over five days of dosing through Day 28 of follow-up, compared to placebo for both dosing groups.

Jay R. Luly, Ph.D., President and Chief Executive Officer of Enanta Pharmaceuticals, commented in a press statement issued on February 17, 2022, “EDP-938 is currently being evaluated in a broad clinical program across multiple patient populations, and we look forward to continuing the development of this important therapy to bring us closer to a treatment for RSV patients.”

The U.S. FDA previously granted EDP-938 Fast Track Designation.

It is differentiated from fusion inhibitors for RSV as this N-protein inhibitor targets the virus’ replication machinery and has demonstrated high barriers to resistance against the virus in vitro. 

Additionally, N-protein inhibitors may be effective treatments at later stages of infection.

RSV vaccine development news is found at PrecisinVaccinations.com/RSV.