(Bloomberg) — Activist investor Starboard Value has taken a stake of about $1 billion in Pfizer Inc. and is seeking to spur a turnaround of the struggling pharmaceuticals giant, according to a person familiar with the matter.

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Starboard has approached former Pfizer executives Ian Read and Frank D’Amelio to aid in its efforts, and they have expressed interest in helping, the person said, asking not to be identified discussing private information. It’s unclear in what capacity they would be involved. Read was Pfizer’s chief executive officer from 2010 to 2018 and chose current CEO Albert Bourla as his successor. D’Amelio was the New York-based company’s chief financial officer from 2007 to 2021.

Starboard’s exact plans and engagement with the company aren’t clear at this time. The activist has found that investors and research analysts are frustrated by the company’s sustained post-pandemic struggles, the person said.

Pfizer declined to comment. Starboard couldn’t immediately be reached for comment.

Shares in Pfizer rose as much as 2.8% Monday at the New York market, moving them into positive territory for the year. That compares with a 21% increase in 2024 for the S&P 500 index.

Pfizer has been struggling to find its next big hit. The company’s Covid-19 vaccine and treatment more than doubled its revenue to $100 billion in 2022 from $42 billion in 2020, but demand for those products has since declined dramatically.

Unconvinced

Wall Street has yet to be convinced Pfizer will be able to replace its pandemic riches. The company has seen its stock price more than halve from its high in December 2021.

Obesity pills were once hoped to be its next big hit, and in early 2023 Bourla himself promised that Pfizer could capture $10 billion of the burgeoning market for drugs related to the GLP-1 protein that Ozempic mimics. He later backtracked.

So far, the obesity push has delivered one drug that flopped entirely, and trials of another twice-daily pill were discontinued due to side effects. While a new once-daily formulation is now in tests, its prospects are uncertain amid fast-growing competition.

Numerous expensive deals under Bourla haven’t turned the stock around. Most recently, Pfizer abruptly announced the worldwide withdrawal of a drug for sickle cell anemia. That drug came through Pfizer’s 2022 acquisition of Global Blood Therapeutics for $5.4 billion. The September withdrawal came the day before European regulators suspended the approval of the drug, citing a higher rate of complications in people that took it.