change in non-Federal price
(1) The term “change in non-Federal price” means, with respect to a covered drug that is subject to an agreement under this section, an amount equal to— (A) the non-Federal average manufacturer price of the drug during the 3-month period that ends with the month preceding the month during which a contract goes into effect (or, in the case of a covered drug for which sufficient data for determining the non-Federal average manufacturer price during such period is not available, during such period as the Secretary considers appropriate); minus (B) the non-Federal average manufacturer price of the drug during the 3-month period that ends one year before the end of the period described in subparagraph (A) (or, in the case of a covered drug for which sufficient data for determining the non-Federal average manufacturer price during such period is not available, during such period preceding the period described in subparagraph (A) as the Secretary considers appropriate).