Medicare Part D plans cut coverage more than commercial plans after IRA changes

New research from the National Pharmaceutical Council finds Medicare Part D plans were more likely than commercial plans to restrict coverage in competitive drug classes after implementation of the Inflation Reduction Act. The analysis says the trend may affect millions of beneficiaries and raise questions about access to branded medicines as Part D redesign continues.

Why it matters: - Medicare beneficiaries are losing coverage for some branded medicines at a faster rate than people with commercial insurance. - The coverage declines affect drugs in competitive classes, where plan design can directly shape access and patient out-of-pocket costs. - The findings add to concerns that Inflation Reduction Act changes may have side effects beyond lower drug spending.

What happened: - National Pharmaceutical Council research published in Health Affairs Scholar found Medicare Part D plans were more likely than commercial plans to restrict coverage in competitive drug classes after IRA implementation. - The study, "Changes in Medicare Part D Coverage in Competitive Classes in the Post-Inflation Reduction Act Landscape: 2024-2026," examined brand-only medicines across Medicare standalone prescription drug plans and Medicare Advantage Prescription Drug plans. - The analysis used commercial insurance as a comparison group. - Competitive classes were defined as classes with at least three commercially available, eligible brand-only drugs. - The IRA’s Part D changes took effect January 1, 2025 and included a cap on patient out-of-pocket costs and higher catastrophic phase liability for plans and manufacturers.

The details: - The study found an average of 4.5 million Medicare beneficiaries, including 2.7 million in PDPs and 1.8 million in MA-PD plans, lost insurance coverage for previously covered branded medicines across 16 competitive classes. - Medicare coverage declined in both 2025 and 2026. - Standalone PDPs saw larger reductions than MA-PD plans. - In 2024, the average share of beneficiaries with coverage was 71.4% in commercial plans, 52.3% in MA-PD plans, and 47.4% in PDP plans. - Coverage decreases from 2024 to 2026 affected more than 5% of beneficiaries for over half of the included drugs in PDP plans, or 30 of 59 drugs. - Those PDP drug-level declines represented at least 1.14 million fewer covered beneficiaries per drug. - At the class level, coverage fell by at least five percentage points on average from 2024 to 2026 in 10 of 16 classes in PDPs, seven of 16 in MA-PD plans, and three included classes in commercial plans. - The study says incentives to increase formulary exclusions may be highest in classes with multiple branded prescription drugs, where plans can use exclusions to negotiate higher rebates.

Between the lines: - The research points to a possible unintended consequence of the IRA: plans may be narrowing formularies to manage costs and leverage rebate negotiations. - The gap between Medicare and commercial coverage suggests Part D redesign may be affecting access differently than employer or other private coverage. - Dr. Campbell, a study co-author and NPC chief science officer, said beneficiaries are losing coverage for certain drugs at a higher rate than those with commercial insurance, and that the pattern is consistent with one theorized unintended consequence of the IRA. - The findings also align with other reported Part D changes, including increased deductibles, shifts to coinsurance and reduced coverage of therapeutic alternatives tied to drugs selected for the Drug Price Negotiation Program.

What's next: - The authors say more research is needed as IRA implementation continues. - The study calls for closer monitoring of Medicare patients’ access to medicines, health outcomes and whether Part D formulary review processes are protecting access. - Future coverage changes could show whether the current pattern persists as Part D rules continue to evolve.

The bottom line: - Medicare Part D beneficiaries appear to be absorbing more formulary restrictions than comparable commercial enrollees, and the coverage trend could shape access to branded drugs for millions of people.