Oct 6 (Reuters) - Activist investor Starboard Value has

taken a stake of about $1 billion in Pfizer and wants

the U.S. drug giant to make changes to turn its performance

around, sources familiar with the matter said on Sunday.

Starboard has also approached Ian Read, a former Pfizer CEO,

and Frank D'Amelio, who served as CFO until 2021, and both have

expressed interest in helping the activist investor, the sources

said.

Read served as CEO until Albert Bourla took the position in

2019. Bourla was instrumental in working with BioNTech to

develop a COVID-19 vaccine.

Pfizer declined to comment and Starboard did not immediately

respond to a Reuters request for comment.

Investors have punished the company as it navigates

sharply lower sales for its COVID vaccines and drugs, a

weaker-than-hoped launch of its respiratory syncytial virus

(RSV) vaccine and disappointing clinical data for an obesity

pill it was developing.

The company's stock price has fallen to $28.58 on Friday

from approximately $41.00 in 2019 when Bourla took over.

While the company was quick in developing the vaccine during

the pandemic, its fortunes have faded since the world

normalized.

Bourla has also invested significantly on acquisitions,

spending some $70 billion since 2020. It bought Seagen for $43

billion, Biohaven for $13 billion, Arena for $6 billion, Global

Blood Therapeutics (GBT) for $5 billion and Trillium for $2

billion.

Some investors have criticized the spree and expressed

particular concern about GBT where its main sickle cell disease

drug had to be pulled off the market and studies were

discontinued because of adverse side effects.

The Wall Street Journal first reported news of Starboard's

stake.

The investment firm has previously pushed for changes at

News Corp ( NWSA ), Salesforce ( CRM ) and Match Group ( MTCH ).