NEW YORK (TheStreet) -- Mylan (MYL) - Get Mylan N.V. (MYL) Report CEO Heather Bresch needs to answer the letter Iowa Senator Charles Grassley's sent her on Monday asking for an explanation about the pharmaceutical company's dramatic increase in EpiPen prices, the senator told CNBC's "Power Lunch" on Thursday afternoon. 

The interview comes after Bresch said she called Grassley two days ago asking to meet up, but he didn't return her phone call, according to a CNBC interview earlier today. 

Someone from Mylan talked with his Chief of Staff, but he's is still waiting for her to answer his letter, Grassley said. He gave her a deadline of September 6. 

"I'm going to wait until then and read on paper their justification for these increases, gigantic increases that they've had that I think are unjustified. And at that point, then we'll have the conversation that she wants to have. But I want my letter answered," he said. 

Mylan isn't the only one to blame because the whole healthcare system is broken, Bresch told CNBC earlier today. 

While the middlemen, such as those who distribute the drugs and insure patients, are important topics to consider when looking at the pricing of drugs as a whole, it doesn't matter so much in Mylan's case, Grassley said. 

"In this particular instance, we got one company with a monopoly on the product going up more than 400%," he explained.

Some company's have tried to release a competing drug, which would drag Mylan's EpiPen prices back down, but the FDA didn't approve them, noted Grassley. He wrote a letter to the FDA asking for an explanation on its rejection of the competing drugs.  

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"Because I think one of the reasons Mylan had the guts to move this price up so rapidly is because they do have a monopoly," Grassley said. 

Separately, TheStreet Ratings objectively rated this stock according to its "risk-adjusted" total return prospect over a 12-month investment horizon. Not based on the news in any given day, the rating may differ from Jim Cramer's view or that of this articles's author.

TheStreet Ratings team rates Mylan as a Buy with a ratings score of B. This is driven by several positive factors, which the team believes should have a greater impact than any weaknesses, and should give investors a better performance opportunity than most stocks the team covers.

You can view the full analysis from the report here: MYL

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