CMS-4215-P represents CMS’ effort to transition from a guidance-based implementation model to a formal regulatory framework that will govern future negotiations, MFP implementation, manufacturer obligations and Part D sponsor requirements.

On June 12, 2026, the Centers for Medicare and Medicaid Services (CMS) issued Proposed Rule CMS-4215-P, which would establish a permanent regulatory framework for the Medicare Drug Price Negotiation Program created by the Inflation Reduction Act (IRA). The proposal would codify numerous aspects of the program that CMS has previously administered through guidance and govern future negotiation cycles beginning with the 2029 initial price applicability year.

Background

The IRA authorized CMS to negotiate maximum fair prices (MFPs) for certain high-spend, single-source drugs covered under Medicare Parts D and B. The first negotiated prices became effective on January 1, 2026, and additional negotiated products will be added in future years.

CMS-4215-P represents CMS’ effort to transition from a guidance-based implementation model to a formal regulatory framework that will govern future negotiations, MFP implementation, manufacturer obligations and Part D sponsor requirements.

Implications for Pharmacies and Other Stakeholders

While much of the proposal focuses on CMS’ interactions with pharmaceutical manufacturers, the rule has important implications for pharmacies and other pharmacy industry stakeholders participating in Medicare Part D networks as the number of negotiated drugs expands, including the following:

Formalization of Medicare Part D Coverage Requirements

CMS proposes to codify existing requirements that Medicare Part D sponsors provide access to selected drugs subject to negotiated pricing.

This proposal is designed to help ensure continued beneficiary access to negotiated drug products and reduce uncertainty regarding plan obligations to cover MFP drugs.

Codification of the Definition of “Negotiated Price”

The proposed rule would formally incorporate statutory requirements governing the prices paid for selected drugs under Medicare Part D, or “negotiated price,” to guarantee that the savings from the Medicare Drug Price Negotiation Program actually reach patients and pharmacies.

Under this proposal, the negotiated price paid to a pharmacy or dispensing entity by a Part D plan—often managed via pharmacy benefit manager (PBM) network contracts—cannot exceed the MFP plus a designated, reasonable dispensing fee.

This provision is particularly significant because pharmacies have been closely monitoring how PBMs and Part D sponsors implement MFP reimbursement at the point of sale. Codification of these requirements stops the PBMs from inflating the benchmark costs for a drug at the pharmacy counter and may provide greater consistency for pharmacy reimbursement.  

Growing Importance of Dispensing Fees for Pharmacies

As additional drugs become subject to MFPs, dispensing fees may become an increasingly important component of overall pharmacy reimbursement.

Historically, dispensing fees often represented a relatively small portion of total reimbursement to pharmacies for many Part D claims. Under an expanded MFP framework, however, dispensing fees may become one of the primary mechanisms available to ensure pharmacies are compensated for the professional and operational costs associated with dispensing negotiated drugs.

Pharmacies should carefully review their network agreements to understand how dispensing fees are calculated and whether those fees adequately reflect actual dispensing costs.

Mandatory Formulary Inclusion

The rule proposes a strict requirement for Part D plans and their PBMs to include any selected drug that has an active MFP directly onto their plan formularies. PBMs will no longer have the discretion to exclude these specific high-cost, negotiated single-source drugs from coverage.

This proposal benefits pharmacies by preventing PBMs from excluding Medicare Part D negotiation drugs from coverage, ensuring consistent patient access to negotiated drugs and enhancing cash flow transparency as pharmacies can track drug access and ensure they are properly compensated for dispensing MFP medications.

Drug Selection and Program Integrity Changes

CMS also proposes revisions relating to drug selection and program integrity safeguards intended to address potential manipulation of statutory eligibility criteria.

For example, the proposed provision would prevent drug manufacturers and PBMs from executing “product hops” in which a drugmaker introduces a slightly altered new formulation right before negotiation to restart the patent clock. CMS proposed a narrow modification to how it identifies qualifying single-source drugs. CMS will aggregate these formulations to ensure they face negotiation together, blocking strategic maneuvers to evade price controls.

Although this primarily affects manufacturers, such a provision may influence which drug products become subject to negotiation in future years.

Takeaways

One of the most significant long-term issues raised by the proposed rule involves the relationship between MFP pricing and pharmacy reimbursement.

Although the IRA establishes maximum prices that may be charged for selected drugs, neither the statute nor the proposed rule establishes minimum pharmacy reimbursement protections.

However, in combination with significant PBM reforms enacted as part of the Consolidated Appropriations Act of 2026, which requires CMS to assess whether reimbursement and fee structures are set at levels that effectively discourage or preclude participation, particularly for independent and community pharmacies, the combined effect of these regulatory initiatives may substantially reshape Medicare Part D pharmacy economics over the coming years.

As CMS continues to expand the Medicare Drug Price Negotiation Program, pharmacies should remain engaged in both the negotiation and PBM reform rulemakings to ensure that beneficiary savings are achieved without jeopardizing the financial sustainability of pharmacy providers or patient access to care.

Pharmacies or other stakeholders seeking to comment or engage with CMS on the proposed rule can do so via the public comment period, which is open through August 17, 2026.

For More Information

If you have any questions about this Alert, please contact Jonathan L. Swichar, Bradley A. Wasser, Nikki Baniewicz, any of the attorneys in our Pharmacy Litigation Group or the attorney in the firm with whom you are regularly in contact.

Disclaimer: This Alert has been prepared and published for informational purposes only and is not offered, nor should be construed, as legal advice. For more information, please see the firm's full disclaimer.