Adds details on other board members in paragraph 3

By Svea Herbst-Bayliss

BEVERLY HILLS, May 7 (Reuters) - Pharmaceutical company Charles River Laboratories CRL.N has reached a settlement with activist investor Elliott Investment Management to add four new directors to its board and launch a strategic review of the business.

Elliott's Global Head of Engagement Steven Barg will join the board along with three other independent directors who have expertise in the pharmaceutical industry, the company said, confirming news Reuters reported earlier on Wednesday.

Rapport Therapeutics RAPP.O CEO Abe Ceesay, former ImmunoGen CEO Mark Enyedy and Rio Tinto Lithium CEO Paul Graves will also join the board.

Elliott has become the largest investor in Charles River, a top research contractor that helps drug makers with clinical trials and is currently valued at $5.7 billion, but its exact stake could not be determined. The firm's holding has not been previously reported.

As part of the settlement, Charles River will initiate a comprehensive strategic review of its business to help push the stock price higher, the sources said, noting this might include finding ways to make the business more efficient among other initiatives.

Charles River's stock fell last month after the U.S. Food and Drug Administration said it plans to phase out conventional animal testing for monoclonal antibodies and other drugs, focusing on more effective and human-relevant methods. Over the last 52 weeks, the stock price has slumped 51% and closed at $115.41 on Tuesday.

Industry analysts said the April sell-off may have been overdone as they see few changes from the FDA's plan for at least a few years. Over the last five years, Charles River supported more than 80% of FDA-approved novel drugs.

Elliott, one of the world's busiest and largest activist investors with roughly $73 billion in assets, has extensive experience investing in healthcare companies including Syneos Health, Cardinal Health CAH.N and Catalent. Barg also sat on the boards of Catalent and Cardinal Health.

Since Elliott's involvement, Cardinal’s stock price has more than doubled, Catalent was acquired by Novo Holdings - the investment firm and holding company managing the assets of the Novo Nordisk Foundation which owns Novo Nordisk NOVOb.CO - at a 40% premium, and Syneos was taken private by Elliott.

(Reporting by Svea Herbst-Bayliss; Editing by Kate Mayberry and Emelia Sithole-Matarise)

((svea.herbst@thomsonreuters.com; +617 233 2138; Reuters Messaging: svea.herbst.thomsonreuters.com@reuters.net))