(Updates stock price, adds background)
Jan 16 (Reuters) - Celgene Corp is in talks to buy Juno Therapeutics Inc, which is working on an experimental gene therapy drug to treat cancer, the Wall Street Journal reported on Tuesday, citing sources familiar with the matter. (on.wsj.com/2EMlysO)
Shares of Juno, which has a market value of $5.57 billion, were up 42 percent at $64.59 in extended trading.
Chimeric antigen receptor T-cell therapy, or CAR T, harnesses the body's own immune cells to recognize and attack malignant cells. Novartis received the first U.S. Food and Drug Administration approval for a CAR T drug last year.
Juno does not yet have any FDA approvals for its CAR T drugs, but it released promising data from early trials for a blood cancer treatment in November.
It has had previous setbacks in developing the treatments, and shut down development of one leukemia treatment due to severe neurotoxicity that led to five patient deaths.
Still, CAR T treatments are expected to be blockbusters for drugmakers, costing up to $500,000 and generating billions of dollars in sales.
Gilead Sciences Inc bought Juno rival Kite Pharma Inc for nearly $12 billion late last year.
The WSJ report comes days after Celgene said it had agreed to acquire Impact Biomedicines for as much as $7 billion, subject to certain milestones associated with regulatory hurdles and sales performance.
Senior executives from some of the largest pharmaceutical manufacturers told Reuters last week that they expect the Trump administration's tax overhaul to accelerate major acquisitions by drugmakers in 2018 after a slow year for deals in 2017. (Reporting by Michael Erman in New York and Ankur Banerjee in Bengaluru; Editing by Susan Thomas)