The company, which negotiates drug prices on behalf of insurers, is implementing the measure on plans to cover two new cholesterol drugs, made by Amgen and Regeneron, partnered with Sanofi. Miller said Tuesday Express Scripts is seeking to limit price increases on the other drugs it covers as well.
"We have told the companies exactly how much they can inflate the price over the course of the contract," Miller said. "If they go up any higher, dollar for dollar it comes back to the plan sponsors."
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In other words, Express Scripts will only pay for drugs up to a certain limit. Miller declined to specify what that limit is.
The strategy comes at a time when price increases on medicines are in the national spotlight, after private company Turing Pharmaceuticals raised the price of a 62-year-old drug by more than 5,000 percent, drawing protests from doctors and patient groups that said they could no longer access it.
Presidential candidate Hillary Clinton called the move price gouging, and has vowed to introduce measures to limit other such price increases if she takes office. Her focus on the issue has sent the biotech industry spiraling lower over concerns of price limits — even as most industry analysts say it's unlikely Congress would pass any such plans.
In recent weeks, serial acquirer Valeant Pharmaceuticals has taken a beating over price increases it's imposed on medicines after obtaining their rights, leading some to question its business model. Valeant's stock is down 28 percent in the last month. The company has defended itself from such criticism.