The Medicare Part D program has 6 protected drug classes to ensure access to medications for beneficiaries with certain diseases. Under this policy, Part D plans must cover “substantially all” of the drugs in these classes of medications, including: anticonvulsants, antiretrovirals, antidepressants, antipsychotics, antineoplastics, and immunosuppressants.

New research from Avalere finds that while only 35% of plan-covered drugs across all 6 protected classes were generic in 2016, the vast majority (91%) of all prescriptions filled were for generic products (Figure 1).

For example, Avalere’s analysis found that 50% of covered drugs in the anticonvulsant class were generic; however, 90% of all anticonvulsant prescriptions filled in Part D were for generic products. A similar relationship was observed for all other protected classes, except antiretrovirals, for which clinical guidelines drive physicians to prescribe therapies not yet available in generic form for the treatment of HIV/AIDS.

Funding for this research was provided by the National Council for Behavioral Health. Avalere maintained full editorial control.

Methodology

Avalere analyzed Medicare prescription drug event (PDE) data for 2016 under the terms of a CMS research data use agreement. PDE data were sampled to ensure that no more than 20% of Medicare beneficiaries were included in any particular protected class analysis. Avalere also used its PlanScape® proprietary database that combines and analyzes the CMS 2016 Public Use Files data, including Part D plan formulary design. We excluded Cost plans, Demo plans, and Programs of All-Inclusive Care for the Elderly plans from the analysis due to the unique benefit design of those plans that would not be representative of the Part D market. Drug coverage statistics were weighted by the plan enrollment. Avalere used publicly available and proprietary databases to identify comprehensive list of national drug codes for medications assigned into the Part D 6 protected drug classes and on the market in 2016.