Drug maker Shire has rejected three takeover bids from Takeda Pharmaceutical that valued Shire at more than $60 billion, according to multiple reports, and now Allergan appears to be entering the sweepstakes, per Reuters.

The bottom line: Acquiring Shire, a large and profitable firm that makes hyperactivity drugs Adderall and Vyvanse among others, would easily catapult Takeda or Allegan into the ranks of the largest global drug manufacturers.