Breakthrough Treatments Could Relegate RSV Seasons Like 2023 To History Books

Posted on Mar 8, 2023

This winter the northern hemisphere has witnessed one of the worst seasons on record for respiratory diseases – the so-called ‘tripledemic’ of Covid-19, flu and RSV.

Cases of RSV (respiratory syncytial virus) were significantly higher this year than in pre-pandemic seasons, compounding pressure on healthcare systems. In the US 90,000 infants have been hospitalised since October, and 14,000 in the UK.

2023 is set to be a game changer in the battle against RSV, with this winter’s outbreak potentially becoming a thing of the past. There are six new vaccines and drugs in phase III development, with some that could be approved and rolled out as early as September. There are five phase III vaccine candidates targeting RSV in elderly adults, one paediatric maternal vaccine and a monoclonal antibody shot to protect newborn babies.

RSV is the leading cause of respiratory hospitalisation in all infants, the majority of whom are healthy and born at full term. Over half (55 percent) of global RSV cases are in infants under 1 years-old, with eight percent in people over the age of 65. The high number of cases in small infants indicates a need to focus prevention efforts in this group.

Sanofi and AstraZeneca have developed a one-shot prophylaxis antibody jab called Nirsevimab which efficacy results have shown it to be 80 percent effective against preventing lower respiratory tract infections in all infants under 1 years old. The drug offers protection for up to five months which would shield infants for their first winter.

It is estimated that the use of Nirsevimab for all infants would reduce hospitalisations by 50 percent in the western world, preventing hundreds of thousands of children becoming severely sick. By preventing severe illness the drug reduces pressure on healthcare systems over critical winter months. It is estimated the universal rollout of Nirsevimab in the US could save USD 630 million in healthcare costs and $30 million in Spain.

Potential healthcare savings can be offset by the treatment cost, which is reported to be $600 in the US and could be less in Europe. The cost effectiveness of the treatment will be a determining factor in how countries decide on introducing Nirsevimab. Airfinity estimates that the drug would need to be priced at £90 for it to be cost effective for all infants in the UK but combining usage with cheaper maternal vaccines could be the most cost effective strategy.

Babies are born throughout the year, but the RSV season occurs during the winter months, meaning a baby born in March could have protection from a maternal vaccine for 6 months but this would wane before the RSV season begins in the autumn. An antibody shot, such as Nirsevimab, could be used to boost protection as the winter months approach. If monoclonal antibodies and maternal vaccines are used strategically to cover the infant population, there could be additional cost savings.

While RSV cases predominantly impact infants, older people make up the greatest proportion of deaths. With over 10,000 deaths reported in the US in 2019 and 6,600 deaths reported in the UK. Five of the vaccines in the pipeline are primarily targeting RSV in elderly people. The candidates from GSK, Pfizer and Moderna all published positive phase III data in the last six months and we are expecting regulatory decisions from FDA on the GSK and Pfizer vaccines in the first half of 2023.

Pfizer and Moderna’s promising phase 3 results showed 67% and 84% efficacy, respectively, at preventing lower respiratory tract infections, and GSK showing 83% efficacy against lower respiratory tract disease, all in the over 60’s.

The approval and rollout of these new vaccines and treatments could prevent us from seeing another winter like this one, but regulatory approvals and equitable access are hurdles which need to be overcome before this may become a reality.

In the US, there is already concern that Sanofi and AstraZeneca’s antibody shot Nirsevimab will not be covered by the Vaccines for Children federal program as it isn’t technically a vaccine, it is an antibody drug. Its exclusion could see it denied to babies from poorer families which are under or uninsured.

Global equitable access is an even bigger hurdle. There is a stark need for preventative RSV treatment in poor countries. In 2019, RSV-attributable acute lower respiratory infections led to more than 100,000 deaths of children under five. 97 percent of these deaths occurred in low- and middle-income countries.

Price is not the only barrier to global access, monoclonal antibodies are harder and more expensive to make than vaccines. While vaccine production is a difficult process, antibody production is more complex, requiring multiple steps, particularly the downstream isolation and purification of them, making it difficult to create larger batches. This could make access more difficult in lower income countries. A silver lining here is that there are five more paediatric RSV vaccine candidates in phase II and III trials which may be easier to manufacture at scale.

2023 will undoubtedly be a groundbreaking year in the fight against RSV but for real progress in global health and outcomes, these new breakthroughs need to benefit everyone.

Read the full article in PharmaBoardroom.

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