(Reuters) - U.S. representatives Jason Chaffetz and Elijah Cummings of the House Committee on Oversight and Government Reform sent a letter to Mylan NV Chief Executive Heather Bresch on Monday asking for documents and communications related to the fast-increasing price of allergy auto-injector EpiPens. Mylan said earlier it would launch the first generic version of EpiPen for $300, half the price of the branded product, in the drugmaker’s second step in less than a week to counter a backlash over the product’s steep price. Chaffetz and Cummings, the committee’s chairman and ranking member respectively, requested documents related to Mylan’s revenue from sales of EpiPens since 2007, manufacturing costs and the amount the company receives from federal health care programs.  