Shares of Ariad Pharmaceuticals Inc. jumped more than 12 percent on takeover fever Thursday after a British news website reported several global pharmaceutical giants had made overtures to the troubled Cambridge maker of a potent leukemia drug.

Ariad relaunched its drug, called Iclusig, last week after regulators pressed the company to halt US sales in October amid mounting safety concerns. Under an agreement with the Food and Drug Administration, chief executive Harvey Berger said the treatment would initially be sold to a smaller subset of leukemia patients for whom no other drugs are effective.

But eventually, Berger told investors at the J.P. Morgan Healthcare Conference, the company plans to “rebuild the confidence in Iclusig” through clinical studies aimed at using it to treat a broader group of leukemia patients and people suffering from other diseases.

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The website of the Mail, quoting unidentified “dealers [who] heard whispers from across the pond,” reported Thursday that at least three international drug makers — Indianapolis-based Eli Lilly and Co. as well as the British giant GlaxoSmithKline PLC, and Ireland’s Shire PLC, whose chief executive is based in Lexington — had made “friendly approaches” to Ariad’s board.

Lilly was prepared to pay $20 a share to gain control of Ariad, the report said.

Ariad’s stock vaulted 81 cents to $7.52 a share, a gain of 12.07 percent on the Nasdaq exchange Thursday, a day when the broader financial markets retreated on economic jitters.

Representatives from Ariad and its reported suitors would not discuss the market frenzy or the Mail’s report, citing longstanding company policies.

“We don’t comment on rumors and speculation,” said Ariad spokeswoman Liza Heapes.

“It is our policy at Lilly not to comment on market rumors or deal speculation,” said Mark Taylor, a spokesman for Eli Lilly.

Shire and GlaxoSmithKline similarly declined to talk about whether they were interested in Ariad.

Once seen as a rising star among Massachusetts biotechs, Ariad lost more than $2.5 billion in market value and was forced to lay off 160 employees last fall after it pulled Iclusig from the market.

Its executives have also been reassessing a plan to move into two buildings in a new corporate and research campus under construction in Kendall Square.