CMS's June 12, 2026 proposed rule moves the IRA Medicare Drug Price Negotiation Program from sub-regulatory guidance to a permanent regulatory framework starting in Initial Price Applicability Year (IPAY) 2029 (up to 20 Part B and Part D drugs selected annually). Key proposals include aggregating hyaluronidase-type reformulations so Maximum Fair Prices (MFPs) apply across dosage forms, sunsetting the small-biotech exception (with a temporary ~66% of Non-FAMP floor for 2029–2030), and establishing strict Part D sponsor formulary inclusion duties. Public comments are due by August 17, 2026, with a final rule expected in Fall 2026.
Biopharmaceutical manufacturer market-access, regulatory affairs, government relations, and portfolio planning teams must quickly digest this first formal notice-and-comment rulemaking. Up to this point, CMS has administered the negotiation program through a sequence of draft and final guidance documents, shielding the agency from formal Administrative Procedure Act (APA) challenges but leaving manufacturers with a shifting, unpredictable operational landscape.
The proposed rule, published in the Federal Register under public inspection number 2026-12059, represents the formalization of the program's long-term rules. As the program expands to its full statutory scale in IPAY 2029, CMS is closing perceived loopholes and expanding its enforcement mechanisms. Sourcing and launch teams must analyze these changes to adapt their life-cycle management strategies.
What does the June 12, 2026 CMS proposed rule change for IRA Medicare drug negotiation?
The proposed rule shifts the program from a collection of temporary guidance letters to a permanent administrative code. The most significant structural change is the transition to Initial Price Applicability Year (IPAY) 2029.
Under the statutory timeline of the Inflation Reduction Act, the scope of selected drugs increases each year:
- IPAY 2026: 10 Part D drugs.
- IPAY 2027: 15 Part D drugs.
- IPAY 2028: 15 Part B and Part D drugs.
- IPAY 2029 and beyond: Up to 20 Part B and Part D drugs selected annually.
By transitioning to a formal regulation, CMS is establishing the administrative framework that will govern this high-volume phase of the program. Market-access teams must recognize that the guidance issued for the first three negotiation cycles will remain in place for those specific cohorts, but the new regulations will apply to all new drug selections starting in 2029.
Furthermore, CMS is proposing changes to the drug eligibility publication process. Instead of publishing the top 50 negotiation-eligible drugs, the agency will publish only the top 30 eligible drugs. This change is designed to reduce market speculation and limit commercial disruption for products that fall just outside the selection threshold.
Administrative Law and Litigation Implications of the Shift to Regulations
CMS's choice to issue a formal Notice of Proposed Rulemaking (NPRM) is a strategic response to ongoing industry litigation. Historically, manufacturers have sued HHS and CMS, arguing that using "guidance" to implement major price controls violates the APA because guidance bypasses the mandatory public comment and agency response requirements. By moving the program into the Code of Federal Regulations (CFR) through notice-and-comment rulemaking, CMS is attempting to insulate the program from future procedural lawsuits.
However, this formalization also gives manufacturers a clearer target. Once the final rule is published, it becomes a final agency action. Manufacturers can then file lawsuits challenging the specific substance of the regulations under the APA, arguing that CMS's interpretations (such as the hyaluronidase aggregation rule) exceed the authority granted by Congress in the text of the IRA.
How would the fixed-combination / hyaluronidase aggregation close the reformulation loophole?
One of the most consequential proposals for portfolio planning is the new fixed-combination and reformulation aggregation rule.
Under current guidance, manufacturers can extend a drug's market exclusivity by reformulating an intravenous (IV) biologic into a subcutaneous injection. A common method is co-formulating the active biologic agent with recombinant human hyaluronidase (an enzyme that increases tissue permeability, allowing large-volume subcutaneous injections). Because a subcutaneous formulation is approved under a separate or supplemental Biologics License Application (BLA), manufacturers have argued it represents a distinct drug that should not inherit the negotiated Maximum Fair Price (MFP) of the legacy IV version.
The Proposed Aggregation Standard
CMS's proposed rule directly targets this strategy. The agency proposes to aggregate all products that share an active moiety or active ingredient, are held by the same NDA or BLA holder (including subsidiaries and licensed partners), and differ primarily by the addition of an ingredient that enables an alternative route of administration.
Specifically:
- Biologic Reformulations: If a manufacturer reformulates an IV biologic by adding hyaluronidase to create a subcutaneous version under the same or related BLA, CMS will aggregate the two products.
- Exclusivity Impact: The subcutaneous formulation will be considered the "same selected drug" as the legacy IV version.
- MFP Application: The negotiated Maximum Fair Price will apply across both the IV and subcutaneous formulations. The subcutaneous version will not receive its own distinct selection timeline or a separate negotiation window.
This proposal represents a major shift. Subcutaneous reformulations have historically been a primary tool for "patent cliff" defense and lifecycle management. If this rule is finalized, manufacturers will no longer be able to shield a high-value molecule from IRA negotiation by transitioning patients to a subcutaneous hyaluronidase version. The MFP will follow the active ingredient across all routes of administration.
Reformulation Aggregation Flow
- Legacy IV Biologic (BLA): Selected based on Medicare spend. A Maximum Fair Price (MFP) is negotiated.
- Hyaluronidase Reformulation (Subcutaneous BLA): Historically launched to extend exclusivity.
- Ruled Aggregation: Under the proposed rule, the subcutaneous BLA is aggregated with the legacy IV BLA, applying the IV version's MFP to the subcutaneous version.
Operational Readiness Checklist for Managed Care Pharmacy and P&T Teams
To prepare for the implementation of the IPAY 2029 cycle and the new regulatory rules, managed care pharmacy and health-system Pharmacy & Therapeutics (P&T) teams should execute the following operational readiness steps:
1. Conduct a Portfolio Impact Assessment
Health-system pharmacy buyers must audit their purchasing history to identify high-volume IV biologics that are likely to be selected in the IPAY 2029 cycle. For these products, teams should identify if a subcutaneous hyaluronidase formulation is currently utilized, and calculate the financial impact of the aggregated MFP pricing across both formulations.
2. Update Electronic Health Records (EHR) and Order Sets
Clinical informatics teams must review and update clinical order sets. If a selected drug's subcutaneous version inherits the legacy IV version's MFP, order sets should be updated to reflect the standardized pricing, and clinical decision support alerts should be aligned to promote the most cost-effective formulation based on outpatient clinic costs versus home-administration options.
3. Review Contract Agreements with 340B and GPO Vendors
Pharmacy operations teams must review their GPO and 340B contract pricing agreements. Under the proposed rule, CMS establishes strict non-duplication rules to prevent manufacturers from being forced to pay both a 340B discount and an IRA rebate on the same unit. P&T teams must coordinate with their 340B third-party administrators (TPAs) to establish audit mechanisms that trace and document every dispensed unit of an MFP-selected drug.
4. Align Prior Authorization Criteria with CMS Clinical Standards
Managed care directors must review their plan's prior authorization (PA) and step therapy protocols for selected drugs. Because CMS will require plan sponsors to cover all selected drugs on formulary and justify any clinical restrictions, plans must ensure their PA criteria are strictly based on FDA-approved labels and clinical guidelines, avoiding restrictions that CMS could interpret as financial steering.
Commercial and Operational Launch Strategies for Subcutaneous Reformulations
If the proposed aggregation rule is finalized, biopharma portfolio managers must rethink their clinical development and commercial launch timelines. The historical model of launching an IV product, waiting several years to establish the market, and then launching a subcutaneous hyaluronidase reformulation to "switch" patients ahead of biosimilar entry will no longer protect the molecule's revenue from Medicare price controls.
Portfolio teams must evaluate three main alternative strategies:
1. Simultaneous Launch (The "SubQ-First" or "Co-Launch" Model)
Instead of spacing the IV and subcutaneous launches years apart, manufacturers may choose to accelerate the clinical development of the subcutaneous formulation to launch it simultaneously with, or shortly after, the IV version. By establishing the subcutaneous version as the primary formulation early in the product lifecycle, the manufacturer can maximize high-margin subcutaneous revenues during the initial years before the molecule becomes eligible for selection (which occurs 11 years after approval for small molecules and 13 years for biologics).
2. Developing Novel Combinations Rather Than Reformulations
CMS's aggregation rule focuses on reformulations that differ "primarily by the addition of an ingredient that enables an alternative route of administration" (such as hyaluronidase). It does not aggregate products that combine the primary biologic with a second active therapeutic agent to treat the disease. Manufacturers may shift their R&D focus toward developing fixed-dose combinations that contain two active moieties. If the second agent provides documented clinical synergy, the combination will be treated as a new drug with its own negotiation timeline, separate from the monotherapy version.
3. Ex-U.S. Subcutaneous Focus
Because the Inflation Reduction Act price controls apply only to U.S. Medicare reimbursement, manufacturers may choose to shift their subcutaneous commercialization efforts to European and Asian markets. In these countries, subcutaneous formulations remain a highly effective tool for reducing hospital infusion costs and maintaining market share under national single-payer pricing models, even if their U.S. commercial utility is reduced by the CMS aggregation rules.
What happens to the small-biotech exception, and what temporary relief does CMS propose?
The Inflation Reduction Act included a statutory Small Biotech Exception designed to protect emerging biotechnology firms from the immediate impact of price negotiations. Under this exception, CMS excluded qualifying small-biotech drugs from selection if the manufacturer met specific criteria regarding total Medicare spend share and company size.
The statutory sunset
By statute, the Small Biotech Exception is scheduled to sunset after IPAY 2028. This means that starting in IPAY 2029, small biotechnology companies will face the same selection and negotiation risk as multinational pharmaceutical corporations.
The Proposed Temporary Pricing Floor
Recognizing the potential impact on research and development pipelines for small firms, CMS has proposed a temporary administrative transition mechanism for IPAY 2029 and IPAY 2030:
- Eligibility: To qualify, a drug must be owned by a manufacturer that meets the historical definition of a small biotech (representing less than 1% of total Medicare Part B or Part D drug spend and where the selected drug accounts for at least 80% of the firm's Medicare revenues).
- Affirmative Application: The manufacturer must submit a formal, document-heavy application to CMS during the selection phase. The exception will not be applied automatically.
- Pricing Floor: For qualifying small-biotech drugs selected in 2029 and 2030, CMS will apply a temporary Maximum Fair Price ceiling (pricing floor) set at approximately 66% of the drug's average Non-Federal Average Manufacturer Price (Non-FAMP).
While this pricing floor provides a temporary buffer, market-access teams at emerging biotech companies must recognize that it is a short-term transition rule. By IPAY 2031, all selected drugs, regardless of manufacturer size, will be subject to the standard statutory MFP calculation methods, which can range from 40% to 75% of the drug's average non-FAMP depending on its market age.
What new Part D formulary duties, enforcement powers, and operational changes does CMS propose?
CMS is proposing operational regulations to ensure that Medicare beneficiaries have immediate, unfettered access to selected drugs at the negotiated Maximum Fair Price.
Part D Formulary Mandates
The proposed rule establishes a strict Part D formulary inclusion duty for plan sponsors:
- Mandatory Coverage: Part D sponsors must include all selected drugs that carry an active MFP on their formularies.
- No Unreasonable Tiering: Sponsors cannot place the MFP drug on a specialty tier with high coinsurance as a way to steer patients toward non-selected alternatives.
- Coverage Rationale: Sponsors must justify any prior authorization (PA) or step therapy criteria applied to an MFP drug, demonstrating that the criteria are based on clinical evidence rather than financial steerage.
Redefining "Negotiated Price"
In the commercial channel, pharmacies buy drugs from wholesalers at wholesale acquisition cost (WAC) and dispense them to patients. To ensure the patient receives the benefit of the negotiated price at the pharmacy counter, CMS proposes to revise the regulatory definition of "negotiated price" under Part D.
Under the proposed definition, the negotiated price used to calculate patient coinsurance at the point of sale must not exceed the negotiated Maximum Fair Price (MFP) plus a reasonable pharmacy dispensing fee. This prevents plans or pharmacy benefit managers (PBMs) from pocketing the difference between the MFP and a higher contract rate.
Expanded Enforcement and Penalties
CMS is proposing a substantial expansion of its audit and enforcement capabilities:
- Corrective Action Bypass: Under previous guidance, CMS typically issued a warning or requested a Corrective Action Plan (CAP) before imposing financial penalties. The proposed rule would allow CMS to immediately levy Civil Monetary Penalties (CMPs) for violations of the negotiation agreement or for failing to provide required data, without a mandatory prior corrective-action step.
- M&A Documentation Duties: If a manufacturer sells a selected drug to another firm, the proposal adds documentation and transition-reporting requirements covering that transaction. Failure to meet the new documentation duties would expose the parties to CMPs.
- Shortened Error-Suggestion Timelines: Manufacturers would have a shortened window to suggest corrections to CMS's eligibility lists or spend calculations. Prior guidance allowed 21 days, and CMS proposes to compress it further so the agency can meet statutory negotiation deadlines.
- 30-Day Equivalent Supply for Short-Course Products: For once-in-a-lifetime treatments (such as gene therapies, select vaccines, and short-course oncology regimens), CMS proposes to define a "30-day equivalent supply" as 12 units to standardize price comparisons against chronic medications.
Payer and Pharmacy Reimbursement Impact under the New Negotiated Price Definition
The proposal to redefine the Part D "negotiated price" as the MFP plus dispensing fees has significant operational consequences for PBMs, plan sponsors, and dispensing pharmacies.
The Flow of Funds and the Chargeback Mechanism
When a Medicare beneficiary fills a prescription for a selected drug, the pharmacy dispenses the product. However, the pharmacy did not buy the drug at the MFP; they acquired it from a wholesaler at a price closer to Wholesale Acquisition Cost (WAC). To prevent pharmacies from taking a financial loss on every MFP dispense, the industry must utilize a complex reimbursement and chargeback flow:
[Manufacturer]
▲ │
│ (Chargeback Paid)
│ ▼
[Wholesaler] <────── (Buys at WAC) ─────── [Pharmacy]
▲ │
│ (Dispenses to Patient)
│ ▼
└───────── (Reimbursement: MFP) ─────── [Patient / Payer]
- Wholesaler Purchase: The pharmacy buys the drug from the wholesaler at WAC.
- Point of Sale: The pharmacy dispenses the drug to a Medicare patient, charging coinsurance based on the MFP.
- Chargeback Claim: The pharmacy submits a chargeback claim through a clearinghouse. The manufacturer pays the wholesaler the difference between WAC and the MFP, and the wholesaler credits the pharmacy's account.
- Operational Lag: If there is a delay in the chargeback clearing process, pharmacies face temporary cash-flow deficits, as they must carry the WAC inventory cost on their books before receiving the MFP credit.
The Impact on Pharmacy Benefit Managers (PBMs)
Historically, PBMs have generated revenue by negotiating manufacturer rebates and maintaining a "spread" between the price charged to the plan sponsor and the price paid to the pharmacy. By locking the Part D negotiated price to the MFP plus dispensing fees, CMS is eliminating PBM spread-pricing opportunities for selected drugs. PBMs will be forced to transition to flat administrative fee structures for these products, reducing their overall margin on high-spend specialty drugs.
What is the rulemaking timeline and what should manufacturer teams file by August 17, 2026?
The release of the Notice of Proposed Rulemaking (NPRM) on June 12, 2026, initiates a strict administrative timeline leading up to the implementation of the IPAY 2029 cycle:
[June 12, 2026] Proposed Rule Released (NPRM 2026-12059)
│
▼
[August 17, 2026] Public Comment Period Closes (Deadline for Manufacturer filings)
│
▼
[Fall 2026] Final Rule Expected (Expected publication of final administrative code)
│
▼
[November 30, 2026] 2028 negotiated prices will post
│
▼
[February 1, 2027] 2029 Selected-Drugs List Published (First cohort under new regulations)
Strategic Manufacturer Action Plan for the Comment Period
Manufacturer teams must organize their clinical, commercial, and legal resources to draft formal, evidence-backed public comments before the August 17, 2026 deadline. Comments should focus on the operational and legal vulnerabilities of the proposal:
- Challenge the Reformulation Aggregation Rule: Manufacturers of subcutaneous biologics should file detailed comments arguing that aggregating reformulations approved under separate BLAs exceeds CMS's statutory authority under the IRA. Comments should detail the distinct R&D investments, clinical trial costs, and patient benefits (e.g., reduced infusion clinic time) associated with subcutaneous formulations, arguing that treating them as the same selected drug penalizes innovation.
- Request Extension of the Small Biotech Pricing Floor: Emerging biotech firms should advocate for extending the 66% Non-FAMP pricing floor beyond the proposed two-year window (2029–2030) or request that the sunset of the exception be delayed, citing the impact on early-stage capital formation for rare disease therapies.
- Audit the 30-Day Equivalent Supply Definition: Manufacturers of oncology and gene therapy products must review the proposed "12 units = 30-day supply" standard. If a therapy is administered as a single dose, representing it as a monthly equivalent can distort the statutory ceiling calculation. Comments should propose alternative, product-specific dosing metrics.
- Oppose Immediate Civil Monetary Penalties: Industry groups should oppose the proposal to bypass Corrective Action Plans, arguing that immediate financial penalties for administrative errors violate due process, especially given the complexity of the new M&A documentation requirements.
FAQs
Does the proposed rule change the drugs already selected for 2026–2028 negotiation?
No. The proposed rule does not retroactively change the drug selections or the negotiated Maximum Fair Prices for the IPAY 2026, 2027, or 2028 cohorts. The administrative guidance documents issued for those initial cycles remain the governing framework for those drugs. The new regulations, once finalized, will govern the selection, negotiation, and compliance processes starting with the IPAY 2029 cycle.
When do the first rules under this regulation take effect, and how many drugs will be selected?
The proposed rule is scheduled to be finalized in the Fall of 2026, with the first active provisions taking effect for the Initial Price Applicability Year (IPAY) 2029 selection process. Under the statutory expansion, CMS will select up to 20 negotiation-eligible Part B and Part D drugs for the 2029 cohort. The list of selected drugs for IPAY 2029 must be published by CMS on or before February 1, 2027.
How does the rule handle biosimilar and generic market entry?
Under the proposed framework, a selected drug will remain subject to the MFP until a generic or biosimilar equivalent enters the market and achieves "bona fide marketing". CMS proposes to evaluate bona fide marketing based on actual sales volumes and market share, rather than the mere date of FDA approval or commercial launch. This prevents manufacturers from launching a token generic (or "authorized generic") with minimal distribution to terminate the MFP negotiation process.
Can a manufacturer withdraw a drug from Medicare to avoid negotiation?
Statutorily, the only way a manufacturer can avoid IRA negotiation is by withdrawing all of its drug products from the Medicare and Medicaid programs entirely. Because Medicare and Medicaid represent over 50% of the U.S. pharmaceutical market, this is commercially impossible for almost all manufacturers. The proposed rule reinforces this barrier by clarifying that the withdrawal process requires a multi-year wind-down period, ensuring that manufacturers cannot execute quick exits to bypass selection.
Sources
- CMS Medicare Drug Price Negotiation Program Proposed Rule (Federal Register Vol. 91, No. 115, June 16, 2026, Public Inspection Doc 2026-12059)
- CMS Fact Sheet: Medicare Drug Price Negotiation Program NPRM (June 12, 2026)
- CMS Negotiation Program NPRM Milestones Timeline
- Inflation Reduction Act of 2022, Pub. L. No. 117-169, § 1191–1198 (42 U.S.C. § 1320f et seq.)
- CMS Announces Manufacturer Participation for the Third Cycle of Medicare Drug Price Negotiation (January 2026)
- Holland & Knight Legal Analysis: CMS Issues First Proposed Rule for IRA Medicare Drug Price Negotiation (June 18, 2026)
