(Reuters) - Mylan NV, which has come under fire for its drug pricing, said on Friday it would start selling a generic version of its life-saving EpiPen allergy treatment for $300 per two-pack, a more than 50 percent discount.

The company has been under investigation by the U.S. government, and its chief executive was called before Congress to testify on raising the price of a pair of EpiPens to more than $600 from $100 in 2008.

Mylan, which first announced it would launch the generic version of its allergy auto-injector EpiPen for $300 in August, said the authorized generic would be available in pharmacies starting next week.

Mylan’s move comes a day after 20 U.S. states filed a lawsuit over pricing against generic drugmakers, including Mylan, Teva Pharmaceuticals and four other generic drugmakers.

The U.S. Department of Justice on Wednesday filed criminal charges against two generic drug industry executives, alleging that they colluded to fix prices and split up market share.

The cases are part of a broader generic drug pricing probe that is under way at the state and federal level, as well as in the U.S. Congress. In 2014, media reports of sharply rising drug prices led to Congressional hearings.

Mylan has been criticized for classifying EpiPen as a generic product, which led to its paying significantly smaller rebates to state Medicaid programs for the poor than if the drug were classified as branded.

The company said in October that it would pay $465 million to settle questions on the impact of the classification on U.S. government healthcare costs.

Mylan said earlier this month it expected to cut less than 10 percent of its workforce to integrate its acquisitions.

Mylan’s shares were up about 1 percent in early trading on Friday.