GSK hails respiratory virus jab after positive trial results

GSK trial results appeared to show that its potential blockbuster vaccine for respiratory syncytial virus is more effective than Pfizer’s, as the rivals compete for a new market protecting older adults against the common lung infection.

In data released on Thursday, GSK said its vaccine showed overall efficacy of 82.6 per cent in a clinical trial, above Pfizer’s previously announced 66.7 per cent, although trials are not always directly comparable.

GSK’s vaccine candidate, which it plans to submit for approval this year, reduced severe RSV disease by 94.1 per cent, above Pfizer’s 85.7 per cent for preventing severe disease. The definitions of severe disease vary slightly between the trials.

Tony Wood, GSK’s chief scientific officer, said RSV remained one of the major infectious diseases without a vaccine, despite 60 years of research.

The disease, which is often confused with cold or flu, affects 64mn people and kills 160,000 a year, hitting older people, especially with underlying conditions, and infants the hardest.

“We believe that with the high vaccine efficacy demonstrated in this pivotal trial, our vaccine candidate has the potential to help reduce the significant global burden of RSV-associated disease in older adults, including those at the greatest risk of severe outcomes,” he said.

The company said the vaccine was safe and well tolerated, with mainly mild and transient side effects.

The vaccine will boost GSK, which despite being one of the world’s largest vaccine makers lagged behind in the race for a Covid-19 jab. It provided its adjuvant, which can improve the immune system’s response to vaccine, to other companies including Sanofi that were far behind Pfizer, BioNTech, Moderna, and Oxford/AstraZeneca. 

Jo Walton, an analyst at Credit Suisse, forecasts that the RSV vaccine market could be worth $6bn at its peak, with GSK taking roughly a third of the market. When choosing a vaccine, she said, health authorities such as the US Centers for Disease Control and Prevention were likely to focus on how well it protects against hospitalisation.

GSK is hoping the RSV vaccine will prove that it can develop new blockbusters and rejuvenate its pipeline of drugs. The company released ambitious targets last year, including aiming to deliver sales of more than £33bn by 2031, after criticism from activist investors including US hedge fund Elliott Management.

Gareth Powell, head of healthcare at Polar Capital, said the RSV vaccine was an “exciting product” but not yet proof of a complete transformation. “I’d still argue that you need further evidence to show the research and development engine cranking,” he said.

GSK and Pfizer are the frontrunners in a race for an RSV vaccine, kicked off again by a breakthrough by Jason McLellan and Barney Graham, scientists at the US National Institutes of Health who showed how to stabilise a key protein. Johnson & Johnson, Bavarian Nordic and Moderna all developing their own candidates.

Emma Walmsley, GSK chief executive, told the Financial Times in July that she believed having more companies selling RSV vaccines would generate more demand.

“The awareness of adult vaccination has boomed meaningfully, for obvious reasons, over the last few years,” she said. “Every family, company, and country can now see the direct economic benefit of preventing disease rather than just treating it. I think the more companies that are involved sometimes can create a bigger market.” 

GSK’s vaccine only includes one strain of RSV, whereas Pfizer used two strains. However, GSK said its vaccine candidate proved highly effective across both the A and B strains. GSK also used its adjuvant to boost efficacy, which Pfizer did not use.

William Gruber, senior vice-president of Pfizer vaccine clinical research and development, said Pfizer did not include an adjuvant because it was one less thing to have to defend amid increasing vaccine hesitancy, particularly when the shot is being developed for pregnant women. GSK has stopped its trial in pregnant women but Pfizer expects to report data for its shot by the end of the year.

“We were obviously interested in not only adults but immunising pregnant women to protect their babies,” he said.