FDA okays Merck's would-be Prevnar rival Vaxneuvance

The FDA has approved a new pneumococcal vaccine from Merck & Co, just over a month after Pfizer got a green light for a new version of its market leading Prevnar shot.

Merck's Vaxneuvance – formerly known as V114 – is the first major competition to Pfizer's franchise in the big market for conjugate pneumococcal vaccines. It covers 15 different pneumococcal serotypes – two more than Pfizer's current Prevnar 13 shot – and has been approved for use in patients aged 18 or over.

Pfizer's updated 20-valent vaccine – Prevnar 20 – has raised the ante on protection however and it remains to be seen how Vaxneuvance will fare in the marketplace.

Prior to COVID-19, pneumococcal vaccines were the largest vaccine market worldwide – estimated at around $8 billion – with Prevnar 13 capturing almost $6 billion of that last year from its use in both the adult and paediatric categories.

In October, a  panel of experts from the Centers for Disease Control and Prevention (CDC) is scheduled to review both the two new vaccines and decide how they should be used in adults, according to Merck.

Prevnar 20 has now been launched at a list price of $232, roughly in line with Prevnar 13, but Merck hasn't yet revealed what it intends to charge for Vaxneuvance.

Merck already sells an older pneumococcal vaccine called Pneumovax 23, which protects against 23 strains but is a polysaccharide based shot, so doesn't stimulate as strong an immune response as the conjugate jabs. It is mainly oriented towards the adult market, which is smaller than the paediatric vaccine market.

The company's aim is to develop Vaxneuvance for childhood vaccinations as well, and the company's chief marketing officer Michael Nally told the Barclays Global Healthcare Conference earlier this year that this will likely be the "primary market" for the shot.

Vaxneuvance cleared two phase 3 trials in children earlier this year, setting up a possible marketing application for paediatric use later this year. That could give it a valuable lead over Prevnar 20, as Pfizer doesn't expect to have its phase 3 results in children until next year.

The vaccine has shown a comparable to Prevnar 13 immune response across all 13 shared serotypes with a greater impact on serotype 3 – arguably the most problematic variant in terms of clinical severity – and the two serotypes only covered by Merck's shot, namely 22F and 33F.

Prevnar 20 meanwhile covers 22F and 33F as well as serotypes 8, 10A, 11A, 12F and 15B, so can boast the broadest range of any conjugate pneumococcal vaccine on the market.

The new shot is however only the first shot across the bows of Pfizer's Prevnar franchise however, as Merck is also working on two follow up vaccines – V116 and V117 – that will extend its range.

V116 is a specifically targeting adult disease, and the most common serotypes that cause disease in older people based on epidemiological data, while V117 is taking the same approach for the paediatric population.

Meanwhile, another rival – Affinivax  – has just reported phase 2 data with a new pneumococcal vaccine that it thinks could five the established companies a run for their money, covering 24 serotypes and stimulating a stronger immune response against key serotypes shared with Prevnar 13. The vaccine is being developed with Astellas.

Also in the running is Vaxcyte, which has a 24-valent shot in early development and hopes to have initial clinical data from that programme in late 2022/early 2023.