The political pressure on pharmaceutical company Mylan continued to grow Wednesday with another Senate committee demanding answers for why the cost of EpiPens has skyrocketed and Hillary Clinton denouncing the price hike on the presidential campaign trail.

Sens. Susan Collins (R-Maine) and Claire McCaskill (D-Mo.), the chair and ranking Democrat of the Senate Special Committee on Aging, sent a letter to Mylan chief executive Heather Bresch seeking information on the company’s pricing practices.

Since 2007, the price of EpiPen, a commonly used epinephrine auto-injector that treats severe allergic reactions, has shot up by 400 percent to $600. Last year, more than 3.6 million prescriptions for EpiPen were written.

“We are concerned that these drastic price increases could have a serious effect on the health and well-being of everyday Americans,” the letter says. “We are particularly concerned that seniors have access to EpiPen because, according to Mylan’s website, older Americans ‘may be at an increased risk of having a more severe anaphylactic reaction if they are exposed to biting and stinging insects.’ ”

The senators are asking Mylan to provide any analysis relating to pricing or market share of EpiPen dating back to 2007, the year Mylan acquired the rights to the device from Merck. It also asks Mylan to provide a briefing to the committee’s staff by Sept. 7.

A Mylan spokeswoman said Wednesday that the company has reached out to every lawmaker who has sent them a letter on the pricing issue and looks forward to meeting with them and responding to their questions.

The EpiPen is a huge moneymaker for Mylan. In 2014, it became the first Mylan product to reach $1 billion in net sales, according to the company’s 2015 SEC filing.

“There’s no denying they raised the price a lot and make more money on this product now than any other product they sell,” said Wells Fargo analyst David Maris.

Clinton, the Democratic presidential candidate, on Wednesday said the price increase is “outrageous” and called on Mylan to immediately reduce the price of EpiPens.

“It’s wrong when drug companies put profits ahead of patients, raising prices without justifying the value behind them,” Clinton said in a statement.

Bresch, Mylan’s CEO, is the daughter of Sen. Joe Manchin III (D-W.Va.), whose office has so far declined to comment.

Lawmakers leading the charge to investigate Mylan say Manchin’s family ties will have no bearing on how the Senate proceeds with potential hearings.

“The issue here is about Mylan’s morally bankrupt price-gouging strategy that has made this lifesaving drug unaffordable to families across America, not the identity of Mylan’s CEO,” said Sen. Richard Blumenthal (D-Conn.), who is calling on the Senate Judiciary Committee and the Federal Trade Commission to investigate potential antitrust violations and deceptive trade practices at Mylan. “If the Senate Judiciary Committee holds a hearing — as I believe it should — it should include consumers, patients, health insurers and appropriate Mylan officials, no matter what their position.”

A spokeswoman for Senate Judiciary Chairman Charles E. Grassley (R-Iowa) said Wednesday that who Mylan’s CEO is “has no bearing on Sen. Grassley’s interest in the issue.”

On Monday, Grassley sent Bresch a letter requesting information about how Mylan determined the price of EpiPens. In the letter, which asks the company to respond by Sept. 6, Grassley says he has heard concerns about the high cost of EpiPens from many constituents, including a man in Iowa who recently had to pay more than $500 to refill his daughter’s EpiPen prescription.

An FTC spokeswoman on Wednesday said the agency does not confirm the existence of, or comment on, investigations, but said it “takes seriously its obligation to take action where pharmaceutical companies have violated the antitrust laws, and it will continue to closely scrutinize drug market competition on consumers’ behalf.”