In Reply As the authors of the 2 letters point out, it was not possible for us to fully characterize net insulin costs to Medicaid programs because of the secrecy of data on the total amounts of manufacturer rebates to Medicaid or average manufacturer prices (AMP), which are protected as companies’ trade secrets by confidentiality agreements and federal statutes. Because of the importance of these measures, the Department of Justice recently initiated an inquiry into how Lilly’s service agreements with wholesalers affects the calculation and reporting of AMP as part of the Medicaid drug rebate program.1