RSV vaccine meets primary endpoint in older adults

2nd February 2023

mRNA-1345 is a vaccine against respiratory syncytial virus (RSV) that showed a high level of efficacy against lower respiratory tract disease

Moderna has announced that mRNA-1345, its investigational vaccine, met its primary endpoint and demonstrated a high vaccine efficacy against RSV-associated lower respiratory tract disease and which was defined by two or more, as well as three or more, symptoms.

The press release relates to the ConquerRSV trial which was a randomised, double-blind trial, designed to evaluate the safety and tolerability of the mRNA-1345 vaccine. The study sought to demonstrate the efficacy of a single vaccine dose in the prevention of a first episode of RSV-associated lower respiratory tract disease when compared to placebo, 14 days after vaccination, through to 12 months. In a site dedicated to the study, individuals are invited to screen for inclusion, highlighting how in the US alone, the virus causes 14,000 annual deaths.

ConquerRSV was reported to have recruited more than 37,000 adults 60 years of age and older. The study’s primary efficacy endpoints were based on two definitions of RSV-lower respiratory tract disease with either two or three or more symptoms.

According the press release, the efficacy of the vaccine was 83.7% (95% CI 66.1 – 92.2%, p < 0.0001) against RVS-associated disease as defined by two or more symptoms. The reported interim analysis was based on a total of 64 cases, 55 of which occurred in those given placebo. In addition, there were 20 cases of RSV-associated lower respiratory tract infections where patients presented with 3 or more symptoms, of which only 3 occurred in patients given the vaccine. This gave a vaccine efficacy of 82.4% (95% CI 34.8 to 95.3%, p = 0.0078) against RSV-associated disease with 3 or more symptoms.

An analysis of safety data showed that mRNA-1345 was well tolerated and there were no safety concerns identified, although this will continue to be monitored as the trial progresses. Commonly reported adverse effects were generally mild to moderate in severity e.g., injection site pain, fatigue, headache, myalgia and arthralgia. In fact, only 4% of systemic adverse reactions reported for the vaccine were grade 3 or higher (i.e., severe) and overall, there were only 3.2% of localised adverse reactions, at grade 3 or above.

Moderna also announced that these findings will be submitted for publication and presented at an upcoming conference and hope to submit all the data for regulatory approval in the first half of 2023.

RSV vaccine shows high efficacy in older adults

19th October 2022

An RSV vaccine provided a high overall efficacy in older adults especially among patients with a severe lower respiratory tract infection

RSV vaccine candidate, RSVPreF3, manufactured by GSK provided a high overall efficacy in a phase 3 trial among older adults according to a press release by the manufacturer.

Respiratory syncytial virus (RSV) is one of the common viruses that cause coughs and colds and causes severe respiratory illnesses in infants and older adults who frequently require hospitalisation. The condition creates a severe disease burden upon sufferers and the global number of hospital admissions for RSV-acute respiratory infections (ARI) in older adults has been estimated at 336000 and which lead to an estimated 14 000 in-hospital-related deaths. Currently, not a single RSV vaccine has been approved although in September 2022, it was reported that Pfizer was ready to file for FDA approval of its candidate RVS vaccine.

The GSK press release relates to their randomised, placebo-controlled trial which was designed to evaluate the efficacy of the RSVPreF3 at preventing lower respiratory tract disease (LRTD) caused by RSV in adults ≥ 60 years of age following a single dose of the vaccine. GSK announced preliminary findings from the study in June 2022 although no data was presented in the release apart from the fact that the vaccine showed statistically significant and clinically meaningful efficacy in adults aged 60 years and above. While the current findings have yet to be published in a peer-reviewed article, the press release does provide plenty of data.

RSV vaccine results

The findings show that among those assigned to RSVPreF3 there were 7 lower respiratory tract RVS cases compared to 40 in the placebo group, giving an overall vaccine efficacy of 82.6% (96.95% CI, 57.9 – 94.1, p < 0.0001). The vaccine also demonstrated a high efficacy against both type A (84.6%) and type B (80.9%) RVS.

In addition, there was a consistently high vaccine efficacy across a range of pre-specified secondary endpoints. For example, among those with a severe lower respiratory tract infection, there was only 1 case in the RSV vaccine group compared to 17 in the placebo arm, giving an efficacy of 94.1% (95% CI, 62.4 – 99.9, p < 0.0001). Among patients with pre-existing comorbidities, such as underlying cardiorespiratory and endocrino-metabolic conditions, vaccine efficacy was 94.6% (95% CI, 65.9 – 99.9) and 93.8% (95% CI, 60.2-99.9) in adults aged 70-79 years.

Among patients with RSV confirmed acute respiratory infections, vaccine efficacy whilst lower, was still high with an overall efficacy of 71.7% and again, this was similar for type A (71.9%) and type B (70.6%).

The RSV vaccine was also well tolerated with observed solicited adverse events typically mild-to-moderate in severity and transient, with the most frequent being injection site pain, fatigue, myalgia, and headache.

The company expects to undertake regulatory submissions based on the phase III data in the second half of 2022.