Pharmaceutical giant Allergan Plc might want to think about patenting its method of eluding generic drug competition--transferring its Restasis patents to an Indian tribe.

Last year, Allergan paid the St. Regis Mohawk Tribe to take its patents on the dry eye drug Restasis to escape a legal challenge by generic drugmakers. The move checked off some key patentability requirements. It was creative (novel), no one had thought of it before (nonobvious), and it would achieve, if...