GSK goes back to its vaccine bread and butter

But breaking Pfizer and Merck’s duopoly will not be easy.

After several disappointing deals in cancer, GSK is going back to what it knows best: vaccines. The purchase of the private group Affinivax, for $2.1bn up front, will give GSK a contender in pneumococcal jabs.

But even if Affinivax’s lead project, AFX3772, makes it to market, GSK will have a tough time going up against Pfizer, which dominates this space. Merck & Co will be another fierce competitor, and various other players are also trying to get a piece of the action.

The rationale behind GSK’s buy is that bigger is better, in terms of vaccine valency. It has been shown that including more disease-causing serotypes decreases the incidence of invasive pneumococcal disease. To this end, Pfizer and Merck last year got the nod for 20-valent and 15-valent vaccines respectively. Affinivax’s AFX3772, meanwhile, is a 24-valent jab.

AFX3772 is set to go into phase 3 in adults “in the short term”, so it should become apparent fairly soon whether adding a handful more serotypes will make a difference in terms of clinical outcomes.

As well as allowing higher valency than conventional conjugated vaccines, Affinivax says its MAPS (multiple antigen presenting system) technology elicits broader T and B-cell responses. The group also has a 30-plus-valent candidate in preclinical development.

Investors in Vaxcyte might be wondering why that company was not selected by GSK: it also has a 24-valent vaccine in phase 2 and a preclinical >30-valent project, Vax-XP.

But perhaps Affinivax presented easier pickings. In early 2021 the group raised $226m in a series C that had the hallmarks of a crossover round, but it never managed to go public. And in February Astellas handed back rights to AFX3772, saying it was prioritising other projects. The Japanese group is eligible for milestones and royalties on the asset.

It will become clear in due course whether Astellas or GSK was right about AFX3772 and Affinivax’s platform more broadly.

Meanwhile, investors and young oncology players alike might be wondering if the impending departure of GSK’s chief science officer, Hal Barron, will herald another strategy shift for GSK. The group, which famously sold off its oncology drugs under Andrew Witty, has in recent years been desperately trying to become a cancer player.

One deal is not a trend, but all eyes will now be on new GSK’s next move.

The multivalent pneumococcal vaccine landscape
Product/project Company Description Note
Prevnar 13 Pfizer/Daewoong 13-valent conjugate vaccine First approved 2010
Prevnar 20 Pfizer 20-valent conjugate vaccine FDA approved in adults Jun 2021; ph3 data in infants due H2 2022
Vaxneuvance Merck & Co 15-valent conjugate vaccine FDA approved in adults Jul 2021; Pdufa in infants Jul 1, 2022 (date extended)
Pneumovax 23 Merck & Co 23-valent polysaccharide vaccine First approved in 1983
Synflorix GSK 10-valent conjugate vaccine Approved in Europe 2009; never launched in US
Phase 3
PCV13i Cansino Biologics 13-valent conjugate vaccine China study in children completes Aug 2022
V116 Merck & Co 21-valent conjugate vaccine Ph1/2 in adults completed, ph3 Stride-7 in HIV pts not yet recruiting
Phase 2
ASP3772 Affinivax (now GSK) 24-valent conjugate vaccine Ph1/2 in adults completed, ph3 to start "shortly"; ph1/2 in children to start 2022
VAX-24 Vaxcyte 24-valent conjugate vaccine Ph1/2 adult study, topline data due end 2022
SP0202 Sanofi/SK Bioscience "Next-generation conjugate vaccine" Infant study completes Sep 2023
Source: Evaluate Pharma &

This story has been updated to clarify the status of Vaxcyte's VAX-24.

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