Eli Lilly’s stock was set to suffer its worst day in four years after sales of diabetes and obesity drugs Mounjaro and Zepbound missed expectations.

Eli Lilly (LLY) agreed to acquire an experimental treatment for breast cancer and other advanced solid tumors from Scorpion Therapeutics for up to $2.5 billion. The purchase price includes an upfront payment and subsequent amounts that Scorpion's shareholders would receive as certain regulatory and sales milestones are achieved.