• Richard Amissah

Background: The divergence between list and net prices for specialty pharmaceuticals—the "gross-to-net bubble"—reached an estimated $356 billion in 2024.¹ Current benefit designs often tie patient coinsurance to list prices while intermediaries retain negotiated rebates, a regressive structure that disproportionately burdens low-income enrollees and reduces adherence to essential biologic therapies.²,³ Objective: To model the actuarial, budgetary, and health equity impacts of a standardized Net-Price Coinsurance and Equity Guardrail (NPCEG) policy across commercial fully-insured and Medicaid Managed Care (MCO) markets. Methods: We developed a comparative static microsimulation using 2022-2024 data from CMS National Average Drug Acquisition Cost (NADAC) files,⁴ SSR Health net pricing estimates,⁵ and Medical Expenditure Panel Survey (MEPS) utilization baselines.⁶ The NPCEG model mandates point-of-sale rebate pass-through for coinsurance calculations and imposes a sliding-scale out-of-pocket (OOP) cap for enrollees <400% of the Federal Poverty Level (FPL). We estimated adherence elasticity using established demand curves for three high-spend therapeutic classes: immunology, oncology, and multiple sclerosis. Results: In base-case simulations representing 10 million covered lives, NPCEG reduced mean annual OOP costs for specialty tier users by 38% ($1,450) in commercial plans. While commercial premiums required a compensatory 2.1% increase to maintain actuarial value neutrality, the model predicted a 14% reduction in therapy abandonment among lowest-quartile income enrollees. In Medicaid MCOs, replacing spread pricing with transparent administrative fees generated sufficient savings (e.g., Ohio's reform saved $186.1 million in its first year⁷) to fully fund the Equity Guardrail without additional state general revenue outlays. Conclusions: Mandating net-price coinsurance is a technically feasible mechanism to de-escalate financial toxicity without requiring direct government price setting. We present a model legislative framework for state implementation that realigns intermediary incentives with patient access goals.

PBM Reform & Equity Disentangling the Gross-to-Net Bubble: A Microsimulation of Net-Price Coinsurance and Equity Guardrails in U.S. Pharmacy Benefits

"PBM Reform & Equity Disentangling the Gross-to-Net Bubble: A Microsimulation of Net-Price Coinsurance and Equity Guardrails in U.S. Pharmacy Benefits", International Journal of Emerging Technologies and Innovative Research (www.jetir.org), ISSN:2349-5162, Vol.11, Issue 2, page no.g999-g1006, February-2024, Available :http://www.jetir.org/papers/JETIR2402725.pdf

"PBM Reform & Equity Disentangling the Gross-to-Net Bubble: A Microsimulation of Net-Price Coinsurance and Equity Guardrails in U.S. Pharmacy Benefits", International Journal of Emerging Technologies and Innovative Research (www.jetir.org | UGC and issn Approved), ISSN:2349-5162, Vol.11, Issue 2, page no. ppg999-g1006, February-2024, Available at : http://www.jetir.org/papers/JETIR2402725.pdf