April 2013 Update to Medicare ASP Files By Debra A. McCurdy on 12 March 2013 Print:Email this postLike this postShare this post on LinkedIn CMS has posted the April 2013 Medicare Part B ASP files. CMS observes that average drug prices in the market generally remain stable, with prices for the top Part B drugs decreasing by 0.5% from the first to second quarter of 2013.