GSK plc has announced the discontinuation of its Phase III development plans for its herpes simplex virus (HSV) vaccine candidate, GSK3943104, after it failed to meet the primary efficacy objective in the Phase II trial. The decision follows a comprehensive analysis of data from the Phase II segment of the TH HSV REC-003 trial.
The TH HSV REC-003 trial, a combined Phase I/II proof-of-concept study, aimed to assess the clinical efficacy of GSK3943104 before advancing it to further clinical development. The results indicated that the vaccine candidate did not achieve the anticipated efficacy, leading to the decision not to proceed with Phase III studies. GSK reported that no safety concerns were observed during the trial.
Unmet Needs in Genital Herpes Treatment
Genital herpes remains a significant public health issue with limited treatment options. GSK emphasized the continued need for innovative treatments for this condition, which is associated with substantial unmet medical needs. The company plans to thoroughly review the data from this and other studies to guide future research and development efforts within its HSV program.
The TH HSV REC-003 study will continue for routine safety monitoring and to collect follow-up data, which may provide valuable insights into the management of recurrent genital herpes. GSK is coordinating with investigators to communicate the trial's outcome to participants.
Trial Design and Endpoints
The TH HSV REC-003 trial (NCT05298254) was a Phase 1/2 study that evaluated the reactogenicity, safety, immune response, and efficacy of GSK3943104 in individuals aged 18 to 60 years with recurrent genital herpes (RGH). Participants were randomly assigned to receive two doses of the non-adjuvanted HSV vaccine or placebo intramuscularly on days 1 and 29. The primary efficacy endpoint was the time to the first confirmed HSV-2 RGH episode, defined as at least one of the lesional or anogenital swabs taken during the suspected episode being positive for HSV-2 as measured by polymerase chain reaction.
GSK's Broader Portfolio and Future Directions
Despite this setback, GSK reaffirms its commitment to addressing the challenges posed by genital herpes and advancing its research initiatives in the field. The company is known for uniting science, technology, and talent to combat diseases.
GSK's pipeline page indicates that it currently has no other candidates for HSV. However, the company intends to evaluate the totality of all data from the TH HSV REC-003 trial and other studies to inform future research and development of its HSV program.
Opportunities for Other Companies
With GSK's departure from the HSV vaccine race, companies such as Moderna and BioNTech, which are actively developing mRNA HSV vaccines, may have an opportunity to address this unmet medical need. Moderna’s therapeutic candidate mRNA-1608 is currently in Phase II development, while BioNTech’s prophylactic candidate, BNT-163, is in Phase I development.
