Glaxo needs a quick recovery from its RSV vaccine stumble

After the spin-out of its consumer business Glaxosmithkline will be all about R&D, so news of a halt on one of its most valuable pipeline projects is a blow. An “observation from a routine safety assessment” prompted recruitment and vaccination to be voluntarily paused across three studies testing Glaxo's maternal RSV candidate GSK3888550A. Exactly what was seen is not being disclosed, but the tolerance of risk in this population must be extremely low. The pivotal Grace trial was due to read out in the second half of this year, so the 10,000-participant study must be close to full enrollment. Encouragingly, a second RSV project is unaffected: GSK3844766A is being developed for older adults – considered a much larger market than maternal – and remains on track to generate pivotal data before mid-year. The two recombinant protein vaccines contain the same RSV antigen, although ‘766A is adjuvanted. Several developers are racing to bring the first vaccine against the respiratory virus to market, so Glaxo needs a quick resumption. The delay cements Astrazeneca and Sanofi’s lead with their long-acting antibody nirsevimab, which was granted a speedy review by EU regulators this week.