Amgen, a California-based biopharmaceutical company, is offering a money-back guarantee to Harvard Pilgrim Health Care and any of its members who use the company’s expensive cholesterol-lowering drug Repatha and fail to obtain the desired results.

According to Harvard Pilgrim, Amgen will offer a full refund on the price of the drug and any copayments if a patient is hospitalized for a heart attack or stroke after taking Repatha for six months or more. The list price of Repatha is $14,100 a year; Harvard Pilgrim officials pay less, but their contract with Amgen does not allow them to disclose the price.

The unusual pricing arrangement, which Harvard Pilgrim described as the first of its kind, is an attempt to pay for drug performance, an approach that has been much talked-about as a way to reduce the rising cost of pharmaceutical drugs. “We hope to negotiate more contracts of this type, in which a pharmaceutical company truly has ‘skin in the game’ going forward,” said Michael Sherman, the chief medical officer of Harvard Pilgrim.

Repatha is given by injection every two or four weeks. It is targeted at patients who have an inherited disorder resulting in high levels of LDL cholesterol or have heart attack or stroke conditions that have been difficult to treat with existing drugs.

Sherman said in an email that several thousand of the health plan’s members meet the criteria for use of the drug. He said the decision about whether to prescribe the drug or not would be left to the treating physician and patient.

The Amgen-Harvard Pilgrim agreement has benefits for both sides. The deal sends a strong signal that Amgen has a lot of confidence in its drug, and Harvard Pilgrim sees its costs drop. Sherman said that even if Repatha is prescribed and used appropriately, some individuals will suffer heart attacks or strokes.  “We would pay for those hospitalizations in any event, with or without this agreement,” Sherman said. “So having the cost of the drug refunded reduces the overall cost.