The pharmaceutical company Mylan is facing more political pressure to confront the price hike of EpiPen after 20 US senators, including Elizabeth Warren and Bernie Sanders, sent an open letter on Tuesday to the company criticising its “exorbitantly expensive” price hikes.

Reports emerged last week that the company had implemented a series of gradual price increases inflating the price of the drug from $56.64 to $317.82, a 461% increase in cost since Mylan acquired the rights to EpiPen in 2007. During that same time, Heather Bresch, chief executive officer of Mylan, saw her pay rise $2,453,456 to $18,931,068, a 671% increase. Last week, she sold 100,200 of her shares in the company for more than $5m.



“The EpiPen auto-injector delivers a life-saving dose of epinephrine to patients suffering from anaphylaxis. Anaphylactic shock can lead to serious injury or death if untreated; thus, making sure the EpiPen is readily available for use is a critical part of life for millions of Americans living with severe allergies,” the Democratic senators wrote in the eight-page letter addressed to Bresch.

“The EpiPen, however, has become so exorbitantly expensive that access to this life-saving combination product is in jeopardy for many Americans.

“Mylan’s near monopoly on the epinephrine auto-injector market has allowed you to increase prices well beyond those that are justified by any increase in the costs of manufacturing the EpiPen,” the senators wrote.

The senators gave Bresch a deadline of 12 September to address seven multi-part questions about the company’s “Savings Card” for customers with insurance, patient assistance program, school programs and plans to release a cheaper generic version of the EpiPen in several weeks. They were sceptical of the company’s attempts to defuse the row, noting that the price of the planned generic “is still three times higher than the cost of the branded EpiPen in 2007”.



Democratic senators Tammy Baldwin, Richard Blumenthal, Barbara Boxer, Sherrod Brown, Joe Donnelly, Richard J Durbin, Al Franken, Heidi Heitkamp, Mazie K Hirono, Amy Klobuchar, Patrick Leahy, Edward Markey, Chris Murphy, Jack Reed, Brian Schatz, Jon Tester, Tom Udall and Sheldon Whitehouse also signed the letter.

Last week, Hillary Clinton commented on the controversy, announcing a plan to reduce drug price increases. In it, the Democratic presidential nominee wrote that manufacturers “should be required to explain significant price increases, and prove that any additional costs are linked to additional patient benefits and better value”. She called on Mylan to reduce the price “immediately”.

Other lawmakers have already written open letters to both Bresch, who is the the daughter of West Virginia senator Joe Manchin, and the Food and Drug Administration. Senators Susan Collins and Claire McCaskill sent a request for information to Bresch from the Committee on Aging. Iowa senator Chuck Grassley and others asked the FDA for suggestions on “alternatives to the EpiPen”. Connecticut senator Richard Blumenthal sent his own letter in addition to the letter sent on Tuesday. “My office has been contacted by dozens of concerned Connecticut residents, families, and first responders who urgently require your life-saving product but fear that its skyrocketing price has put it out of reach,” Blumenthal wrote last week.

The Guardian has reached out to Mylan for comment.