A top Democrat has joined a growing chorus of lawmakers who are angry over a roughly 500 percent price hike for EpiPens and want to hold a hearing to find out why.

Rep. Elijah Cummings, D-Md., echoed calls for the House Oversight Committee to bring the CEO of Mylan to Congress to answer for the price increase for the allergy treatment, which in some cases shot up from $57 a dose in 2007 to $364 last year. Cummings is the top Democrat on the committee.

"It's unconscionable that Mylan is taking advantage of a group of people who desperately need their medication to prevent life-threatening allergic reactions, but I can't say that I am surprised," Cummings told the Washington Examiner.

Cummings noted that prior investigations he spearheaded into the drug industry found CEOs are more interested in "lining their pockets" than providing affordable drugs.

Cummings and Sen. Bernie Sanders, D-Vt., wrote to Mylan in 2014 asking the drug maker to explain price increases for certain generics as part of a larger investigation into higher generic prices. EpiPen was not among the drugs listed in the letter, but others included were the asthma treatment albuterol sulfate, whose price increased by 4,000 percent from 2013 to 2014.

The House Oversight Committee held a hearing in February on generic drug companies that are selling drugs for rare diseases at high prices. The committee featured limited testimony from infamous former pharmaceutical CEO Martin Shkreli, who once led the drug maker Turing that raised the price of an old anti-malarial drug by 5,000 percent.

The hearing also featured testimony from executives with Valeant Pharmaceuticals, which raised the price of two older generic heart drugs.

The Oversight Committee received the request for a hearing on Tuesday from Rep. Grace Meng, D-N.Y., and there have been discussions about it, according to a House aide. Republican committee staff have scheduled a call with Mylan, and Democrats are waiting to hear whether a hearing will be scheduled.

On the Senate side, Sens. Claire McCaskill, D-Mo., and Susan Collins, R-Maine, wrote to Mylan on Wednesday seeking answers about the spike.

The senators asked for a briefing from Mylan CEO Heather Bresch, who is the daughter of their colleague, Sen. Joe Manchin, D-W.Va.

Sens. Chuck Grassley, R-Iowa, and Richard Blumenthal, D-Conn., also have asked for answers.