Potential Impact of the Medicare Prescription Payment Plan for Medicare Part D Beneficiaries With a Cancer Diagnosis

PURPOSE To address high out-of-pocket (OOP) medication costs among Medicare Part D beneficiaries, the 2022 Inflation Reduction Act introduced the Medicare Prescription Payment Plan (M3P), a voluntary program that allows beneficiaries to spread OOP costs over the calendar year. We examined M3P's potential impact among beneficiaries with cancer, who frequently incur substantial early-year Part D medication costs. MATERIALS AND METHODS We evaluated a 2022 5% random sample of Medicare beneficiaries with a cancer diagnosis and ≥1 fill for a cancer-indicated Part D medication. We estimated 2025-adjusted annual true OOP spending and median monthly beneficiary OOP payment obligations with and without M3P enrollment. Subgroup analyses were performed by demographics, nonadherence status in 2022, and Part D benefit phase. RESULTS Among 168,480 beneficiaries with cancer, most were diagnosed with breast (47.6%), dermatologic (17.6%), or prostate (13.3%) cancers. Overall, 46.7% were projected to reach catastrophic coverage in 2025, with 32.4% doing so in January. Breast (29.7%), prostate (21.20%), and hematologic (20.0%) cancers were most common among those reaching catastrophic coverage. Overall, 43.0% were nonadherent to cancer-indicated Part D medications, with 31.5% reaching catastrophic coverage in January 2025. M3P reduced beneficiary payment obligation variability, especially among those reaching the catastrophic phase in January (IQR, $1,798 US dollars [USD] no M3P v $118 USD M3P). Of those reaching catastrophic coverage with a cancer-indicated drug (58.6% overall), 89.2% did so in January. CONCLUSION Early-year entry into catastrophic coverage is common among beneficiaries with certain high-cost cancers. M3P may most effectively reduce financial burden when enrollment occurs before January. Targeted outreach from cancer care teams and Part D plans to nonadherent patients and those considering costly therapies could maximize program impact and improve treatment outcomes.