Glaxo holds its breath

A late-stage hit with its respiratory syncytial virus jab would be a huge validation for the group’s new focus.

Though the separation of Glaxosmithkline's consumer care business Haleon is grabbing much of the attention, the group has another, strictly biotech, catalyst coming up. A pivotal trial of its respiratory syncytial virus (RSV) vaccine in the elderly is due to report by mid-year, and a great deal is riding on the results. 

The shot is Glaxo’s most valuable pipeline project, with some banks forecasting peak sales well into the billions despite the presence of jabs from Pfizer and Moderna in the late-stage pipeline. But Glaxo’s transition to pure-play biopharma raises the stakes: without the consumer care buffer, a negative readout could really hurt.

Project GSK3844766A 
Company Glaxosmithkline
Market cap $108bn
Product NPV $3.0bn
% of market cap 3%
Event type Phase 3 trial results
Indication Respiratory syncytial virus 
Date H1 2022

RSV is often thought of as a childhood disease, but in elderly people, especially those with asthma, heart disease or chronic obstructive pulmonary disease, the virus can be very severe and even fatal.

GSK3844766A is an adjuvanted vaccine containing a recombinant subunit pre-fusion RSV antigen (RSVPreF3). Its phase 3 efficacy study, Aresvi 006, has signed up 25,000 adults aged over 60.


The trial’s primary endpoint is RSV with lower respiratory tract disease (RSV LRTD), which is a proxy for more severe infection. Analysts from Berenberg believe that efficacy of 90% or above would make ’766A “a clear winner”. Above 70% efficacy is likely to be viewed positively by the market, they add. 

Below that would be a disappointment. A vaccine with less than 70% efficacy might still be approvable, but might well be superseded by a superior competitor jab, Berenberg points out. And there are several vaccines from big pharma and others on which late-stage data in this same setting are imminent. 

Currently Glaxo is leading in terms of forecast sales, with $765m pencilled in for 2026 according to Evaluate Pharma’s sellside consensus. This has come down recently, however; at the end of last year 2026 forecasts sat at $1bn. This pre-dates the toxicity worries raised with Glaxo’s similar maternal RSV vaccine, GSK3888550A. Still, Berenberg puts peak sales of the adult vaccine at £3.7bn ($4.9bn).

Pfizer’s candidate takes second place, with 2026 forecasts of $444m; Leerink analysts forecast 2030 sales of $1.3bn here, so ’766A does not have a monopoly on blockbuster expectations. 

But success with an adult RSV vaccine is nowhere near as crucial for Pfizer as it is for Glaxo. For the UK company, the Aresvi 006 readout will be the first event by which investors judge New Glaxo’s R&D fortunes, and a miss will not be taken lightly.

Late-stage pipeline of adult RSV vaccines
Product Company Description Details 
GSK3844766A Glaxosmithkline Protein subunit vaccine, adjuvanted Ph3 Aresvi 006 trial in adults ≥60, data due H1 2022
Pfizer Protein subunit vaccine Ph3 Renoir trial in adults ≥60, data due H1 2022
Ad26.RSV.preF Johnson & Johnson Adenovirus type 26 viral vector vaccine  Ph3 Evergreen trial in adults ≥60, data due H2 2022
MVA-BN RSV Bavarian Nordic Recombinant antigen vaccine Ph3 trial in adults ≥60, data due H2 2023
mRNA-1345 Moderna mRNA vaccine encoding RSV glycoprotein F Ph3 portion of ph2/3 ConquerRSV trial in adults ≥60 began Feb 2022
Source: Evaluate Pharma.

Share This Article