Most Favored Nation Model

CMS published a final rule in the Federal Register on December 27, 2021, that rescinds the November 27, 2020, MFN Model interim final rule with comment period and removes the associated regulatory text at 42 CFR part 513 (these actions withdrew the MFN Model), effective February 28, 2022. See CMS-5528-F at: We will continue to carefully consider the stakeholder feedback we received as we explore all options to incorporate value into payments for Medicare Part B drugs, improve access to evidence-based care, and reduce drug spending for consumers and throughout the health care system.

The proposed Most Favored Nation (MFN) Model would have tested an innovative way to lower prescription drug costs by paying no more for high-cost Medicare Part B drugs and biologicals (hereinafter called “drugs”) than the lowest price that drug manufacturers receive in other similar countries. The MFN Model would have tested paying comparable amounts to the lowest price, adjusted for purchasing power, paid by any country in the Organisation for Economic Co-operation and Development (OECD) that has a Gross Domestic Product (GDP) per capita that is at least 60 percent of the U.S. GDP per capita. The model also would have tested a single add-on payment per dose and waive beneficiary cost sharing for this payment. The model would have operated for seven years, from January 1, 2021, to December 31, 2027.

The public comment period for the MFN Model Interim Final Rule with Comment Period (IFC) ended January 26, 2021.

Update on Status of MFN Model Implementation

On December 28, 2020, the U.S. District Court for the Northern District of California issued a nationwide preliminary injunction in Biotechnology Innovation Organization v. Azar, No. 3:20-cv-08603, which preliminarily enjoins HHS from implementing the Most Favored Nation Rule. Given this preliminary injunction, the MFN Model was not implemented on January 1, 2021 and will not be implemented without further rulemaking.

The order may be found below:

Other Court Orders

On December 23, 2020, the U.S. District Court for the District of Maryland issued a temporary restraining order in Association of Community Cancer Centers v. Azar, No. 8:20-cv-03531, which temporarily restrains HHS from implementing, enforcing, or otherwise effecting the Most Favored Nation Rule for a period of fourteen days. On January 6, 2021, the Court extended the temporary restraining order through January 20, 2021.

The order and accompanying memorandum may be found below:

On December 31, 2020, the U.S. District Court for the Southern District of New York issued a preliminary injunction in Regeneron Pharmaceuticals v. United States Department of Health and Human Services, No. 7:20-cv-10488, which preliminarily enjoins HHS from applying the Most Favored Nation Rule to Regeneron's drug EYLEA.

The order may be found below:

August 6, 2021 MFN Model Notice of Proposed Rulemaking (NPRM) (CMS-5528-P)

CMS is proposing to rescind the November 2020 MFN Model interim final rule with comment period in a notice of proposed rulemaking published in the Federal Register on August 10, 2021. See CMS-5528-P at: We will continue to carefully consider the comments we received on the November 2020 interim final rule as we explore all options to incorporate value into payments for Medicare Part B drugs and improve beneficiaries’ access to evidence-based care.  

The public comment period for the MFN Model NPRM (CMS-5528-P) ends October 12, 2021.


High drug prices are impacting the wallets of Medicare beneficiaries through increased drug coverage premiums and increased out-of-pocket costs. Increases in drug spending are accelerating at a rate that significantly outpaces the growth in spending on other Medicare Part B services, and prices in the U.S. for most Medicare Part B drugs with the highest Medicare spending far exceed prices in other countries. According to a November 20, 2020 Issue Brief from the Department of Health and Human Services, Office of the Assistant Secretary for Planning and Evaluation (ASPE), between 2006 and 2017, Medicare Part B FFS drug spending per enrollee grew at 8.1 percent, more than twice as high as per capita spending on Medicare Part D (3.4 percent) and nearly three times as high as overall retail prescription per capita drug spending (2.9 percent). Spending and enrollment projections by the CMS Office of the Actuary (OACT) for the 2021 President’s Budget suggest that per capita spending on Medicare Part B physician-administered drugs and separately-payable hospital outpatient drugs will grow at a very similar annual rate of 8 percent between 2020 and 2027, before consideration of any COVID-19 pandemic impacts. Overall, Medicare beneficiaries and the Medicare program are bearing unnecessary, potentially avoidable costs for Medicare Part B drugs.

Model Design

The MFN Model was a mandatory, nationwide model that would test whether more closely aligning payment for Medicare Part B drugs with international prices and removing incentives to use higher-cost drugs can control unsustainable growth in Medicare Part B spending without adversely affecting quality of care for beneficiaries. The design of the MFN Model included several key elements:

1. Model Drug Payment:

  • MFN Price: Instead of paying solely based on manufacturers’ average sales price (ASP), Medicare would have paid based on a blending formula that includes the lowest adjusted international price, (the “MFN Price”) for the drug, which would be based on the lowest GDP-adjusted price paid by an OECD member country with a GDP per capita (based on purchasing power parity) that is at least 60 percent of the U.S. GDP per capita, and the ASP.
  • Phase-in over 4 years: The MFN Price would have been phased-in over the first 4 years of the 7-year model, phasing in 25 percent per year for years 1-4, and would have been 100 percent of the MFN Price for years 4-7. For example, for the first year the phase-in calculation would use 75 percent of the ASP and 25 percent of the MFN Price. In years 4-7, the MFN Price would be fully phased-in. However, CMS would have accelerated the blending formula for a drug in years 1-4, if U.S. prices rose faster than inflation and the MFN Price.
  • Will not exceed ASP: To lower what beneficiaries pay, the formula would not allow the model payment amount for a drug (before the per-dose add-on) to exceed the ASP.

2. Alternative to ASP Add-on Payments: The current add-on payment based on 6 percent of ASP for the individual drug would be replaced with a flat payment per dose that is uniform for all included drugs in the MFN Model. The per-dose add-on was calculated using 6.1224 percent of 2019 historic spending for the cohort of drugs included in the first year of the model. CMS bumped up the 6 percent add-on from 2019, to equal 6 percent post-sequestration prior to calculating the per-dose add-on and applying an inflationary factor for the model start and quarterly thereafter.

3. MFN Participants in a Mandatory, Nationwide Model: The MFN Model was a mandatory, nationwide model that required participation from Medicare-participating providers and suppliers that receive separate Medicare Part B fee-for-service payment for the model’s included drugs, with certain exceptions.

MFN Model Participants

MFN participants would have included Medicare-participating physicians, non-physician practitioners, supplier groups (such as group practices), hospital outpatient departments (HOPDs) including 340B covered entities, ambulatory surgical centers (ASCs), and other providers and suppliers that received separate Medicare Part B fee-for-service payment for the model’s included drugs, with certain exceptions noted below. Model participation was mandatory for the included providers and suppliers in all states and the U.S. territories.

Certain types of hospitals and clinics will not participate in the model (such as cancer hospitals, children’s hospitals, critical access hospitals, rural health clinics, federally qualified health centers, and Indian Health Service facilities). Participants in certain other Innovation Center models testing fully capitated or global payment for outpatient hospital services for Medicare FFS beneficiaries, including Medicare Part B drugs, were excluded for the first and second quarters of performance year 1 and would continue to be excluded from the MFN Model thereafter as long as those models incorporate savings on Medicare Part B drug spending under the MFN Model.

Included Drugs

The MFN Model focused on a set of approximately 50 Medicare Part B drugs that encompass a high percentage of Medicare Part B drug spending. CMS identified the included drugs for the first year based on annual Medicare Part B spending in 2019 after excluding certain claims (for example, claims for drugs used at home), and excluding certain types of drugs (such as certain vaccines, oral drugs, multiple source drugs, intravenous immune globulin products, and drugs for which there is an Emergency Use Authorization (EUA) or approval by the Food and Drug Administration (FDA) to treat patients with suspected or confirmed coronavirus disease 2019 (COVID-19)). CMS would have added drugs to the model annually to include drugs that rise to be among the top 50 drugs based on updated annual Medicare Part B spending, after applying certain exclusions. Drugs already included in the model would remain in the model, with limited exceptions.

Quality Measures and Evaluation

The MFN Model would have used a survey-based quality measure to monitor beneficiaries’ experience of care during the model, and CMS would have conducted a variety of analyses to monitor access to the included drugs and assess early effects of the model. CMS would have also conducted a model evaluation. In order to effectively evaluate a nationwide, mandatory model, CMS would have employed an evaluation design that did not require an independent comparison group to establish the counterfactual (what would have happened in the absence of the MFN Model).


Beneficiaries would have fully maintained their choice of providers and treatments. Beneficiary cost-sharing would be waived for the per-dose add-on amount, further reducing what beneficiaries would have paid for the included drugs beyond expected reductions in cost-sharing as drug payments decline to align with the lowest adjusted international price. In addition, CMS would have provided additional beneficiary protections such as enhanced monitoring and Medicare Beneficiary Ombudsman supports.

Provider Protections

The MFN Model included a financial hardship exemption for certain MFN participants whose revenue would have been significantly affected by the MFN Model.

Additional Information

Regulations and Notices

For questions regarding the MFN Model, please email:

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