Without revealing specific details, GSK announced that it is terminating the development of its investigational herpes simplex virus vaccine after failing to meet the study’s primary efficacy objective.
GSK on Wednesday announced that it is discontinuing the development of its early-stage herpes simplex virus vaccine, which will not advance to Phase III studies after failing the TH HSV REC-003 proof-of-concept study.
The pharma did not say what specific efficacy metric the vaccine candidate failed to satisfy, only revealing that it “did not meet the study’s primary efficacy objective.” The study found no safety concerns with the investigational shot, which was dubbed GSK3943104.
Highlighting the “unmet medical need and burden” in patients suffering from herpes simplex virus (HSV), GSK said that it will continue to collect safety and other follow-up data from TH HSV REC-003, which could “offer valuable insights into recurrent genital herpes.” The company’s findings will help the pharma “progress future research and development” of its HSV program.
According to GSK’s pipeline page on its website, it has no more candidates for HSV.
TH HSV REC-003 was a randomized and observer-blinded study that was conducted in two parts: the first enrolled healthy volunteers between the ages of 18 to 40 years, while the second recruited patients with recurrent genital herpes, aged 18 to 60 years. According to its clinicaltrials.gov page, the study tested three formulations of the vaccine candidate, with or without an adjuvant, against placebo. A total of 342 patients were enrolled in the trial.
The study’s primary outcome was the proportion of patients that hit a “solicited administration site event,” which include pain, redness and swelling, within seven days after the first vaccine dose, and then again after the second dose given at day 29. The study also evaluated systemic effects, such as fever, fatigue, headaches and muscle pain.
Aside from safety outcomes, TH HSV REC-003 also looked for signals of efficacy for the vaccine candidate, particularly in terms of confirmed HSV-2-related recurrent genital herpes episodes.
HSV is a common infection that often has no signs or causes only mild symptoms. In more severe cases, it can lead to painful and recurring blisters, while newly contracted infections can manifest as fevers, body aches and swollen lymph nodes. There are currently no cures or vaccines for HSV.
Moderna is advancing an HSV vaccine with its mRNA-based shot mRNA-1608, which is currently in a Phase I/II study in the U.S., according to a company announcement in March 2024. BioNTech is also developing an HSV vaccine, dubbed BNT163, which in December 2022 entered its first-in-human Phase I trial.
