GSK plc (LSE/NYSE: GSK) today announced that it has completed the primary objective data analysis from the phase II part of the TH HSV REC-003 trial. This trial is a combined phase I/II proof-of-concept study to assess potential clinical efficacy of GSK3943104, an early-stage therapeutic herpes simplex virus (HSV) vaccine candidate, before progressing it for further clinical development.

Results show that GSK3943104 did not meet the study's primary efficacy objective. This vaccine candidate, therefore, will not progress to phase III studies. No safety concern was observed. The TH HSV REC-003 study will continue for routine safety monitoring and to generate follow-up data that could offer valuable insights into recurrent genital herpes. GSK is working closely with investigators to inform trial participants.

Given the unmet medical need and burden associated with genital herpes, innovation in this area is still needed. GSK intends to evaluate the totality of all these data and other studies to progress future research and development of its HSV programme.

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Cautionary statement regarding forward-looking statements

GSK cautions investors that any forward-looking statements or projections made by GSK, including those made in this announcement, are subject to risks and uncertainties that may cause actual results to differ materially from those projected. Such factors include, but are not limited to, those described under Item 3.D "Risk factors" in GSK's Annual Report on Form 20-F for 2023, and GSK's Q2 Results for 2024.