In the single-dose vial form, Restasis is available as the generic drug cyclosporine. But Restasis Multidose only comes as a brand-name drug. It’s not currently available in a generic version.

Allergan has constructed a network of legal defences to protect Restasis, a blockbuster with sales of around $1.5 billion a year, from generic competitors. Bryson said a new formulation involving ...