The nation’s biggest pharmacy benefits manager has decided to cover two new drugs that lower artery-clogging cholesterol but raise concern over prices that can top $14,000 a year.

Express Scripts said Tuesday that it will pay for prescriptions of Amgen’s Repatha as well as Praluent from Sanofi and Regeneron Pharmaceuticals under a few conditions designed to control costs.

The decision comes as soaring drug prices draw criticism from patients, doctors and politicians, as well as insurers and employers that generally pay most of the prescription bill. Praluent and Repatha both stirred worry, in particular, because of their potential to be used by millions of patients.

The biologically-engineered drugs are considered the first major advance in managing cholesterol since the introduction of statin drugs more than 20 years ago. They aim to lower bad, or LDL, cholesterol, and analysts expect them to generate billions in sales. More than 73 million U.S. adults, or nearly one-third, have high LDL cholesterol, according to the Centers for Disease Control and Prevention.

The Food and Drug Administration approved Repatha and Praluent earlier this summer for patients with the highest risk of developing heart problems.

Express Scripts said Tuesday that it negotiated a discount it declined to detail on the prices of those drugs. It will require prior approval from one of its pharmacists before any prescriptions are filled.

A spokesman for insurer UnitedHealth Group, which runs a big pharmacy benefits management business, said it had yet to decide on coverage. CVS Health said in August it would not cover the new drugs under its formulary until they have been reviewed by an expert committee.