As a result, the company said it is ending the Mosaico study begun in 2019 with some 3,900 cisgender men and trans people who have sex with other cisgender men and/or trans people.

The selection of trial participants was based on 2016 data from the US Centers for Disease Control (CDC) that found gay and bisexual men to account for more than half of all HIV patients and the majority of new infections. Earlier data found that trans women were nearly 49 times more likely to have HIV compared to all adults of reproductive age.

This is the second setback for J&J on an HIV vaccine after a similar regimen ran aground in a Phase 2b trial in August 2021. The Imbokodo study tested the shot in about 2,600 women in sub-Saharan Africa. At best, the shot was found to be 25% effective, but in some cases it had no effect at all.

The Mosaico study, conducted as part of a private-public partnership that included the National Institute of Allergy and Infectious Diseases and the US Army Medical Research and Development Command, started in 2019 and ended in October 2022, In it, volunteers received four doses of the company’s adenovirus vector vaccine over the course of a year. A soluble protein was added in the third and fourth visit.

Commenting on the trial’s end, Penny Heaton, global therapeutic area head, Vaccines at Janssen Research & Development, said the company was “disappointed” but remains steadfast in its commitment to advancing innovation in HIV.

Pharma analysts are skeptical about the outlook for J&J vaccines altogether after the recent failures. As one noted, the company’s single-dose Covid-19 vaccine has been beset by problems and is now seldom used in vaccination campaigns.

What’s more, Moderna has pulled ahead in the race to develop a safe and effective respiratory syncytial virus (RSV) vaccine. In a report from its Phase 3 trial earlier this month, Moderna said its vaccine was 83.7% effective against RSV-associated lower respiratory tract disease defined by two or more symptoms among trial participants that were at least 60 years old.

Author: Dede Williams, Freelance Journalist