operated prescription drug plan defined For purposes of this part, the term Medicare operated prescription drug plan means a prescription drug plan that offers qualified prescription drug coverage and access to negotiated prices described in section 1860D–2(a)(1)(A). Such a plan may offer supplemental prescription drug coverage in the same manner as other qualified prescription drug coverage offered by other prescription drug plans. (d) Monthly beneficiary premium (1) Qualified prescription drug coverage The monthly beneficiary premium for qualified prescription drug coverage and access to negotiated prices described in section 1860D–2(a)(1)(A) to be charged under a Medicare operated prescription drug plan shall be uniform nationally. Such premium for months in 2019 and each succeeding year shall be based on the average monthly per capita actuarial cost of offering the Medicare operated prescription drug plan for the year involved, including administrative expenses. (2) Supplemental prescription drug coverage Insofar as a Medicare operated prescription drug plan offers supplemental prescription drug coverage, the Secretary may adjust the amount of the premium charged under paragraph (1). (e) Use of a formulary and formulary incentives (1) In general With respect to the operation of a Medicare operated prescription drug plan, the Secretary shall establish and apply a formulary (and may include formulary incentives described in paragraph (2)(C)(ii)) in accordance with this subsection in order to— (A) increase patient safety