Jan 12 (Reuters) - Shares in Abivax ABVX.PA soared 23%, exceeding 121 euros, on Monday after a media report said U.S. pharma giant Eli Lilly LLY.N was still interested in buying the French biotech company.

French media La Lettre reported on Monday that Eli Lilly was ready to buy Abivax for 15 billion euros ($17.5 billion), almost double its current market capitalisation.

Abivax and Eli Lilly did not immediately respond to a Reuters request for comment.

Abivax CEO Marc de Garidel, attending JPMorgan Healthcare Conference in San Francisco, told Bloomberg News that big pharma could no longer ignore the company's key drug obefazimod, which he said may become "one of the most-used products in the next decade".

The experimental drug is being developed for use in the treatment of ulcerative colitis.

"We are concentrating on developing this drug, bring it to the market," de Garidel told BiotechTV. "That's all that matters. The rumours, speculations, we have no control over those."

Brokerage Kepler Cheuvreux said in a note to clients that "Abivax has become a highly attractive late-stage M&A target" following positive phase 3 trial results on obefazimod, which drove Abivax's shares more than 500% higher on July 23.

The shares on Monday were tracking their biggest one-day rise since then, after peaking at record-high 130 euros per share earlier in the session.

Kepler analysts estimated that in a takeover scenario the stock could reasonably trade between 150 and 250 euros per share, reflecting "control premiums, synergies, and the strategic value of a late-stage oral IBD (inflammatory bowel disease) asset".

($1 = 0.8563 euros)