OBJECTIVES: The Inflation Reduction Act (IRA) will have several downstream impacts on the cost of healthcare for the U.S. population. This study aimed to assess the potential evolution of the uptake and net sales of different drug classes in the next decade following passage of the IRA.

METHODS: To illustrate how the IRA may impact drug classes differently in the coming years, we selected Shingrix (Zoster Vaccine Recombinant, Adjuvanted) for the prevention of shingles (herpes zoster) and Imbruvica (Ibrutinib), a kinase inhibitor indicated for several blood cancers. We evaluated the impact of Medicare Part D benefit redesign, selection by HHS for Medicare price negotiation, increased Medicare rebates, and eligibility for or exemption from subsequent price re-negotiation triggered by “long monopoly” status (16+ years since approval) to estimate the impact on annualized Medicare Net Sales for each product through 2030 vs. a 2022 baseline.

RESULTS: Net sales trends diverge between the 2 products, with Shingrix Medicare net sales peaking at225% of 2022 levels by 2028, driven by elimination of copays for Part D vaccines leading to reduced abandonment rates or increased adherence rates, followed by a subsequent decrease to 167% in 2030. For Imbruvica, increased Medicare rebates and the introduction of a negotiated Maximum Fair Price in 2026 reduce Medicare net sales to 60% of 2022 levels by 2029 and 37% by 2030 following price re-negotiation.

CONCLUSIONS: The analysis illustrates how the IRA will have disparate impact on drugs depending on various factors including drug class, current adherence rates, and net price per patient, leading to either increased or decreased Medicare net sales. This impact is not limited to currently marketed drugs but may extend to novel drug development with industry possibly shifting away from development of the most at-risk drug classes in favor of classes with additional protections.