The Janssen Pharmaceutical Companies of Johnson & Johnson has commenced the Phase III EVERGREEN clinical trial of its experimental adult vaccine against the respiratory syncytial virus (RSV), which reduces lower respiratory tract disease (LRTD) in elderly patients.

The randomised, double-blind, placebo-controlled Phase III efficacy trial will analyse the efficacy, safety and immunogenicity of the vaccine against placebo in nearly 23,000 adult subjects aged 60 years and above.

Participants will be enrolled in North America and some nations across Europe, Asia and the Southern Hemisphere.

In the trial, subjects will be randomised to receive either a single vaccine dose or a placebo. After one year, subjects who were given the active vaccine will be re-randomised to receive either the vaccine or placebo.

The participants will also be followed up for a minimum of two RSV seasons.

Janssen began the EVERGREEN trial based on positive data from the Phase IIb CYPRESS trial.

The CYPRESS study assessed the efficacy and safety of the RSV vaccine against LRTD in vaccinated adults aged 65 and above in the US.

Janssen Research and Development Vaccines global therapeutic area head Penny Heaton said: “Positive data from our first RSV vaccine efficacy study and the initiation of the Phase III EVERGREEN study are crucial milestones in the clinical development of our investigational RSV adult vaccine, which has the potential to safely and effectively prevent lower respiratory tract disease caused by RSV in older adults.

“With no vaccine or broadly-indicated antiviral treatment available, preventive solutions to address the significant morbidity and mortality in older adults caused by RSV have long been an unmet need.”

The US Food and Drug Administration granted Breakthrough Therapy status for the vaccine in September 2019 to prevent LRTD caused by RSV in adults aged 60 years or above.

Janssen reported positive data from the Phase III UNIVERSE trial, where the oral suspension formulation of Xarelto (rivaroxaban) was linked to reduced blood clots in paediatric Fontan procedure patients.