Under activist fire, GSK's CEO bet on an RSV vaccine first and kept her job
Elliott demanded GSK's CEO reapply for her job; she answered with an RSV shot that beat Pfizer to market, two-thirds of the US market, and a 22% stock gain.
What was changed
Emma Walmsley was at her most vulnerable when news of Elliott's stake emerged in 2021, four years into her tenure at the UK's second-largest drugmaker. GSK had failed to develop a timely Covid shot while AstraZeneca succeeded, share performance lagged, patents on a key medicine were expiring, and the acquisitions meant to bridge the gap were costly. Elliott — whose campaigns preceded at least five CEO exits — said in a letter to the board that GSK had 'lost its way', though it also called the vaccines business 'one of the crown jewels' of the industry.
The counterweight came from the division that had disappointed during the pandemic. GSK's scientists began a decisive RSV vaccine trial just as Elliott built its stake, started the final trial six months before Pfizer after data modelling showed the virus would resurface once lockdowns eased, and posted results showing almost 83% efficacy — far above the 50-60% benchmark typical for flu vaccines. GSK won the race to US approval in early May 2023. 'We came from being two years behind to being first out the gate,' Walmsley said.
The commercial fight was, in vaccine commercialization head Christi Kelsey's words, 'hand-to-hand combat': GSK became the sole supplier for older adults at CVS Health, the largest US pharmacy chain, and scooped up two-thirds of the market share, with the shot now outselling Pfizer's in the US. Behind the scenes, Walmsley had replaced 100 of GSK's 125 top managers, chief scientific officer Tony Wood reprioritized R&D funding (R&D ran at 14% of sales versus AstraZeneca's more-than-25%), and relations with Elliott warmed into regular meetings.
By May 2024 the stock was up 22% for the year, surpassing AstraZeneca and Pfizer, Elliott's stake was worth about 30% more, and four analysts had upgraded outlooks since January. The caveats remain: the stock trades at a 40% discount to AstraZeneca, US litigation over Zantac persists — GSK denies the cancer claims — and one top shareholder questions whether R&D processes have truly improved.
Why it worked
GSK's Covid vaccine failure and patent cliff left it visibly behind AstraZeneca when Elliott's stake surfaced.
Elliott's own letter called vaccines a crown jewel — making the RSV program the fastest credible proof of the strategy.
Walmsley chose engagement over battle, executing the investor's separation demand while keeping the CEO chair.
What can be applied
When an activist attacks leadership, the best defense is a product win only you could have shipped: listen to the demands, keep the conviction, and let a market-leading launch answer.
Aftermath
The RSV shot's launch and the management overhaul carried the 2024 share recovery; challenges that remain are the valuation discount to AstraZeneca, the Zantac litigation, and the open question of whether GSK's R&D engine now produces a steadier flow of new medicines.