Eli Lilly ( LLY -6.59%) is the most valuable healthcare stock in the world, with a market capitalization of around $720 billion. For a while, it looked like it might be on track to be the first healthcare company to top a $1 trillion valuation, perhaps as early as this year.

Eli Lilly agreed to acquire Scorpion Therapeutics’ breast cancer treatment program for up to $2.5 billion in cash.

Shares of Eli Lilly & Co. LLY slipped 6.59% to $744.91 Tuesday, on what proved to be an all-around great trading session for the stock market, with the S&P 500 Index SPX rising 0.11% to 5,842.91 and the Dow Jones Industrial Average DJIA rising 0.