(Bloomberg) -- Novartis AG’s plan to link the payment for a new heart-failure treatment to the medicine’s performance is meeting skepticism from the largest manager of drug insurance benefits in the U.S.

Novartis said Wednesday that it plans to offer an outcomes- based plan for its newly approved drug Entresto. Insurers would initially pay a lower price, followed by an additional payment if Entresto succeeds in keeping patients out of the hospital and reducing associated costs. The drug could cost as much as $4,500 a year and would be taken daily for a patient’s lifetime.

The problem is that performance-linked prices are difficult to manage because so many things can affect a patient’s outcome, said Steven Miller, chief medical officer of Express Scripts Holding Co., which helps companies and insurance plans manage their prescription benefits.