GlaxoSmithKline plc announced that it has voluntarily paused enrolment and vaccination in the GRACE phase III trial (NCT04605159), evaluating its potential respiratory syncytial virus (RSV) maternal vaccine candidate, as well as two other trials investigating this candidate in pregnant women (NCT04980391, NCT05229068).

The GRACE study was launched in 2020 and evaluates the safety of GSK's candidate vaccine (GSK38888660A) for pregnant mothers and infants and how it affects infants born to vaccinated mothers. The product contains a recombinant subunit pre-fusion RSV antigen that has shown positive safety and immunogenicity results in a Phase I/II trial presented at the ID Week Congress in October 2020.

This decision was made following a recommendation from the Independent Data Monitoring Committee based on an observation from a routine safety assessment. Monitoring safety signals is an integral part of the clinical development process for potential new vaccines.

This decision does not impact the ongoing AReSVi 006 phase III trial (NCT04886596) for RSV older adults (60 years and above). This trial remains on track with an anticipated data readout in the first half of 2022.

In its statement, GSK noted that monitoring safety signals is part of the Committee's routine task and is vital to the development process. The company added that the pause does not in any way impact the ongoing AReSVi 006 Phase III study for older adults aged 60 years and up and that it remains on schedule to deliver its first data readout in the first half of 2022.

GlaxoSmithKline will provide a further update on the respiratory syncytial virus (RSV) maternal vaccine candidate in due course.

Respiratory syncytial virus is an important indication for GlaxoSmithKline, with investment in the space contributing to a recent 34 per cent jump in spending on vaccine R&D, and 2022 is shaping up to be a key year for its attempt to claim a significant slice of a market targeted by rival companies including AstraZeneca, Sanofi and Pfizer.