The author is not precluded from doing so through the use of "cost/cure" or "cost/year of life gained". If efficacy and tolerability is demonstrated, however, then a simple comparison of "cost/course of treatment" can suffice for the purpose of comparing two or more therapeutically equivalent treatment alternatives.
The author is not prevented from utilizing "cost/cure" or "cost/year of life gained". However, if the efficacy and tolerability of treatments are confirmed, then a comparison focusing on "cost/treatment duration" can be employed to compare various therapeutic alternatives that are considered equivalent in effectiveness.