Medicare Part D plans cut coverage more than commercial plans in key drug classes

New National Pharmaceutical Council research finds Medicare Part D plans were more likely than commercial plans to restrict coverage in competitive drug classes after the Inflation Reduction Act took effect. The analysis of 2024-2026 formulary data suggests millions of beneficiaries lost access to branded medicines, with the sharpest declines in standalone Part D plans.

Why it matters: - Medicare beneficiaries may face fewer covered drug options than people with commercial insurance in competitive therapeutic classes. - The coverage changes affect access to branded medicines and may influence out-of-pocket costs, formulary choices and treatment continuity. - The findings add to evidence that some IRA-related Part D changes could have unintended access consequences.

What happened: - The National Pharmaceutical Council published research in Health Affairs Scholar on coverage changes in competitive drug classes after the Inflation Reduction Act. - The analysis covered 2024-2026 formulary data for Medicare standalone prescription drug plans, Medicare Advantage Prescription Drug plans and commercial insurance. - Medicare Part D plans were more likely than commercial plans to restrict coverage for brand-only medicines in competitive classes. - The study defined competitive classes as those with at least three commercially available, eligible brand-only drugs.

The details: - The IRA changed Part D benefit design on Jan. 1, 2025, including a cap on patient out-of-pocket costs and higher catastrophic-phase liability for plans and manufacturers. - The study found that, on average, 4.5 million Medicare beneficiaries lost coverage for previously covered branded medicines across 16 competitive classes. - That total included 2.7 million beneficiaries in standalone Part D plans and 1.8 million in Medicare Advantage prescription drug plans. - Medicare coverage declined in both 2025 and 2026, with larger reductions in standalone Part D plans than in 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. - At the drug level, coverage declines from 2024-2026 affected more than 5% of beneficiaries for 50.9% of the included drugs, or 30 of 59, in PDP plans. - Those PDP declines represented at least 1.14 million beneficiaries lost per drug. - At the class level, average coverage fell by at least five percentage points from 2024-2026 in 10 of 16 classes in PDPs, seven of 16 in MA-PD and three classes in commercial plans. - The research says incentives to exclude drugs may be highest in therapeutic classes with multiple branded prescription medicines, where plans can use exclusions to negotiate higher rebates.

Between the lines: - The study suggests Part D plans may be responding to IRA-era financial pressures by tightening formularies rather than preserving broader brand coverage. - Dr. Campbell, 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. - The pattern is consistent with one theorized unintended consequence of the IRA, according to Dr. Campbell.

What's next: - The authors said more research is needed as IRA implementation continues. - They called for closer monitoring of Medicare patients' access to medicines, health outcomes and whether Part D formulary review processes are protecting access. - NPC directs readers to more information and says the organization follows on LinkedIn.

The bottom line: - Medicare Part D coverage has narrowed more than commercial coverage in several competitive drug classes, and the gap appears to have widened after the IRA changes took effect.