ViroPharma Inc., of Exton, said it agreed to buy options that could total $90 million for the purchase of Meritage Pharma Inc., a private company based in San Diego that has focused on developing treatments for a chronic inflammatory disorder of the esophagus.

ViroPharma paid $7.5 million already. It will pay $12.5 million more for drug development and exclusive right to buy the company after successful completion of the second phase clinical trials of oral budesonide suspension.

At the next milestone, ViroPharma can buy Meritage for $69.9 million, plus other incentives.    - David Sell