Pharmaceutical company Mylan (MYL) has reduced the cost of EpiPens for some people after coming under fire from politicians — but at the end of the day, its CEO told CNBC on Thursday she has a business to run.

"I'm running a business," Mylan's chief executive officer, Heather Bresch, said on " Squawk Box ." "We have over 600 products here in the United States that we got mid-single-digit erosion — decreases. No one was talking about price decreases, but that does happen in the industry to keep medicine affordable."

The price of the EpiPen, a lifesaving medication and delivery system for people with severe allergies, has increased more than 400 percent in the past decade, outraging many parents and prompting senators and Democratic presidential nominee Hillary Clinton to question the pricing process.

Before Bresch appeared on CNBC, the company announced it is reducing the cost of EpiPens through the use of a savings card that will cover up to $300 for the EpiPen 2-Pak. Patients who were previously paying the full price for the EpiPen will have their out-of-pocket cost cut by 50 percent. Mylan also is doubling the eligibility for its patient assistance program.

"The fight on the $300 billion pharmaceutical market is real, and we need to fix it, because it's not sustainable," Bresch said. "We are going to continue to run a business, and we are going to continue to meet the supply and demand that's out there."

Bresch said Mylan subsidizes EpiPens in many parts of the world, but it has invested resources into a broken health-care system in the U.S. and in raising patient awareness.

"We've put hundreds of millions of dollars behind it," Bresch said.

Watch the full interview with Mylan CEO Heather Bresch here.