Shares of Ariad Pharmaceuticals plunged as much as 15 percent after Sen. Bernie Sanders criticized the price of the company's leukemia drug on Twitter.
@SenSanders: Drug corporations' greed is unbelievable. Ariad has raised the price of a leukemia drug to almost $199,000 a year.
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The stock ended the day down about 14.8 percent at $11.14 a share.
In a statement, Ariad said, "our pricing reflects our significant investment in R&D, our commitment to the very small, ultra orphan cancer patient populations that we serve and the associated risk with research and development."
The company added that it spent 143 percent of its total revenue in 2015 in research and development for treatments of rare cancers.
The key biotech ETF has fallen 21 percent in 2016, as the sector faces renewed criticism on the campaign trail. Last month, Hillary Clinton proposed a consumer response team that would monitor drug prices and impose penalties for unjustified price increases.
"Over the past year, we've seen far too many examples of drug companies raising prices excessively for long-standing, life-saving treatments with little or no new innovation or R&D," Clinton said in a statement.
Even with Friday's decline, ARIAD shares have surged 78 percent so far this year.