"In 2013, Sanofi began selling Auvi-Q, which works to quell life-threatening allergic reactions, just as EpiPen does. Sanofi priced Auvi-Q on equal footing with EpiPen. And, initially, Sanofi claims it showed promise of gaining market share and providing real competition to EpiPen, which at the time had more than 99 percent of the market, according to Mylan. But that all changed when Mylan began using dirty tactics, Sanofi alleges."
Looks like Sanofi sold the product to another company - the $4500 number is a price from the company Kaléo.
"In 2015, Sanofi pulled Auvi-Q following quality control issues. The device has since been put back on the market by another pharmaceutical company, Kaléo. The list price of the newly released Auvi-Q is set at $4,500."