A Formulary Change Notice Is Not a Patient-Level Coverage Decision

The Notice Is a Plan-Policy Record; the Coverage Determination Is a Patient-Level Decision

In specialty pharmacy intake hubs, manufacturer patient-support centers, and physician practice reimbursement offices, few documents create more operational confusion than a mid-year letter titled Notice of Formulary Change or Upcoming Changes to Your Prescription Drug Coverage. When an established patient on chronic maintenance therapy receives a notice stating that their drug will require new prior authorization (PA), step therapy, or quantity limits starting next month, case managers frequently panic. Intake coordinators log the letter as an adverse event, draft immediate appeal letters, or notify the prescriber that coverage has been terminated.

This operational response confuses two legally distinct instruments: a plan-level policy announcement and a patient-level coverage determination. A formulary change notice is a broadcast communication issued by a plan sponsor or pharmacy benefit manager (PBM) alerting members and providers that the plan's general rules of coverage are evolving. It is not an adjudication of an individual claim, it is not a revocation of an existing authorization number, and it does not trigger Medicare Part D redetermination rights.

The definitive statutory and regulatory boundary is established under Title 42 of the Code of Federal Regulations. Under 42 CFR 423.566(b), the actions that constitute a Medicare Part D coverage determination are strictly enumerated. A coverage determination consists of:

• A decision not to provide or pay for a Part D drug—including a decision not to pay because the drug is not on the plan's formulary, because the drug is determined not to be medically necessary, because the drug is furnished by an out-of-network pharmacy, or because the plan determines that the drug is otherwise excludable under section 1862(a) of the Social Security Act if applied to Part D—that the enrollee believes may be covered by the plan.

• Failure to provide a coverage determination in a timely manner, when delay would adversely affect the health of the enrollee.

• A decision concerning a tiering exception request under 42 CFR 423.578(a).

• A decision concerning a formulary exception request under 42 CFR 423.578(b).

• A decision on the amount of cost sharing for a covered Part D drug.

Notice what is entirely absent from this authoritative legal list: a general formulary change notification, a Health Plan Management System (HPMS) negative change transaction, an Annual Notice of Change (ANOC) formulary line, and an informational transition letter. None of these administrative communications are coverage determinations. When a plan sponsor alters its formulary, it updates a corporate rulebook; it does not adjudicate a patient file.

This distinction is reinforced by the mandatory content requirements set forth in 42 CFR 423.120(f)(4). The regulation dictates that when a Part D sponsor provides written notice of a negative formulary change to an affected enrollee, the notice must specify: the name of the affected drug; whether the drug is being removed, moved to a higher cost-sharing tier, or subjected to new or more restrictive prior authorization, step therapy, or quantity limits; the reason for the change; alternative drugs on the formulary in the same or lower tier with expected cost sharing; and, except for market withdrawals under 423.120(e)(2)(ii), the means by which the enrollee may obtain a coverage determination under § 423.566, including an exception under § 423.578.

This regulatory mandate is the definitive answer to the operator's dilemma: the formulary change notice explicitly directs the enrollee to the coverage-determination process. If the notice were itself a coverage determination, it would trigger immediate Chapter 423 Subpart M appeal rights (such as an expedited or standard Level 1 Redetermination) and would be rendered on CMS's mandatory standardized denial instrument. Instead, it instructs the reader how to initiate an adjudication if and when coverage is formally contested.

Similarly, when a patient presents a prescription at a retail or specialty counter and a claim rejects because newly instituted prior authorization edits are in place, the pharmacy generates a point-of-sale (POS) rejection accompanied by CMS-10147 (Medicare Drug Coverage and Your Rights). CMS-10147 is not a denial of coverage; it is a statutory notice informing the beneficiary that the pharmacy cannot dispense the drug under the presented claim and outlining their right to contact their plan sponsor to request an official coverage determination under 42 CFR 423.566. Conflating any of these informational touchpoints with an actionable denial leads case managers to file premature appeals that are dismissed for lack of an adjudicative case file.

Classify the Part D Change Before Treating Current Users as Cut Off

Before an operator can assess how a formulary change notice impacts an individual patient, they must classify the underlying change under Medicare Part D regulations. Under 42 CFR 423.100, a negative formulary change is defined as: (1) removing a drug from a formulary; (2) moving a drug to a higher cost-sharing tier; or (3) adding or making more restrictive prior authorization, step therapy, or quantity limit requirements. Crucially, safety-based claim edits (such as automated drug-drug interaction or maximum daily dose safety blocks) that are not submitted to CMS as part of the formal formulary package are explicitly excluded from the definition of negative formulary changes.

Equally important is the regulatory definition of an affected enrollee under 42 CFR 423.100: a Part D enrollee who is currently taking a covered Part D drug that is subject to a negative formulary change, where that change affects the enrollee's access to the drug during the current plan year. If a plan sponsor adds prior authorization criteria that apply exclusively to new therapy starts—or if an enrollee is already authorized under clinical criteria that the new policy does not restrict—that enrollee is not an affected enrollee under the regulation, and no individual written notice is required.

When a negative change does occur, 42 CFR 423.100 and 423.120 divide the operational universe into four distinct regulatory categories:

1. Maintenance Changes: The listed 42 CFR 423.100 maintenance categories, including a negative change to a drug within 90 days of adding a corresponding drug on the same or a lower tier with the same or less restrictive PA, step therapy, or quantity limits (other than an immediate substitution); a negative change to a reference product within 90 days of adding a non-interchangeable biosimilar on those same terms; removing a non-Part D drug; adding or tightening PA, step therapy, or quantity limits based on a new FDA-mandated boxed warning; removing a withdrawn drug if the sponsor does not treat the removal as immediate; removing a drug based on long-term shortage and market availability; making negative changes based on new clinical guidelines or information or to promote safe utilization; and adding PA to help determine Part B versus Part D coverage.

2. Non-Maintenance Changes: Any negative formulary change that is not a maintenance change or an immediate negative formulary change. Discretionary commercial shifts—such as preferring a competing single-source brand or moving a specialty therapy to a higher tier—are non-maintenance only when they do not fit a listed maintenance basis such as a corresponding-drug add, a new boxed warning, shortage, or new clinical guidelines.

3. Immediate Negative Substitutions: Under 42 CFR 423.120(e)(2)(i), a sponsor may, without a negative-change request, make a negative change to a brand-name drug, reference product, or brand-name biological product within 30 days of adding a corresponding drug on the same or a lower tier with the same or less restrictive PA, step therapy, or quantity limits, if that corresponding product could not have been included on the initial CMS-approved formulary because it was not yet available. Advance general notice and retrospective enrollee notice still apply under 423.120(f)(2) and (f)(3).

4. Market Withdrawals: Immediate removal of a drug that the FDA or manufacturer has withdrawn from commercial distribution for safety or effectiveness reasons under 42 CFR 423.120(e)(2)(ii).

The procedural protections afforded to beneficiaries differ dramatically between maintenance and non-maintenance changes under 42 CFR 423.120(e)(3). For maintenance changes, negative change requests submitted by sponsors through HPMS are deemed approved 30 days after submission unless CMS notifies the sponsor otherwise. For non-maintenance changes, however, sponsors are legally prohibited from implementing the change until they receive affirmative, explicit notice of approval from CMS.

Most importantly for patient-advocacy and reimbursement teams, 42 CFR 423.120(e)(3)(ii) establishes an explicit grandfathering mandate: affected enrollees are exempt from non-maintenance negative formulary changes for the remainder of the contract year. If a Part D sponsor receives CMS approval in June to add restrictive prior authorization to an existing specialty brand for commercial reasons, a patient currently taking that drug cannot be subjected to that restriction during that calendar plan year. Treating a mid-year non-maintenance change notice as an immediate cutoff for an established patient directly violates federal exemption rules.

Federal regulations also impose a seasonal blackout on mid-year formulary disruption. Under 42 CFR 423.120(e)(4), except for immediate substitutions and market withdrawals under 423.120(e)(2), a sponsor may not make a negative formulary change that takes effect between the beginning of the annual coordinated election period described in 42 CFR 423.38(b) and 60 days after the beginning of the associated contract year. For calendar-year Part D contracts, that window runs from the October 15 AEP start through March 1 of the contract year. The purpose is to keep the published formulary stable for beneficiaries who select a plan during open enrollment.

What Happens to an Authorization That Already Exists

When a formulary change notice arrives announcing that a therapy will soon require prior authorization or step therapy, what is the legal status of a prior authorization or exception that the plan has already approved for that patient? The answer depends on the legal character of the existing approval.

First, consider an approved exceptions request. Under 42 CFR 423.578(c), a decision by a Part D plan sponsor concerning an exceptions request constitutes a formal coverage determination under § 423.566. The regulation establishes an explicit continuity protection: the sponsor may not require the enrollee to request approval for a refill, or a new prescription to continue using the Part D prescription drug after the refills for the initial prescription are exhausted, as long as (A) the enrollee's prescribing physician or other prescriber continues to prescribe the drug; (B) the drug continues to be considered safe for treating the enrollee's disease or medical condition; and (C) the enrollment period has not expired.

This means that if a patient was granted a formal formulary or tiering exception under § 423.578, a subsequent mid-year notice announcing new prior authorization criteria cannot override that granted exception during the active enrollment period. The exception's duration is governed by federal regulation, not by a subsequent administrative formulary update. If the enrollee renews membership for the subsequent plan year, the sponsor may choose to continue coverage, but it is not required to do so beyond the contract boundary.

Second, consider a standard formulary prior authorization approval. Standard PA approvals are typically issued with stated effective and expiration dates. A later formulary-change notice is not, by itself, a coverage determination that cancels that stated window. Whether a particular authorization number still pays after a maintenance utilization-management overlay is an adjudication fact; this article does not estimate how often that happens.

A general formulary notice announcing that a drug will require prior authorization on a future date is not itself a decision to terminate an in-force authorization. Operators should read the authorization's own stated end date and test the next claim rather than treating the notice date as an automatic expiry.

Third, consider the role of Part D transition fills under 42 CFR 423.120(b)(3). The Medicare transition process is a regulatory safety net for enrollees prescribed Part D drugs that are not on the formulary, including formulary drugs that require PA or step therapy. It must apply to new enrollees after AEP, newly eligible Medicare enrollees, people who switch plans after the contract year starts, and current enrollees remaining in the plan who are affected by formulary changes. When a temporary fill is required, 42 CFR 423.120(b)(3)(iii) requires a one-time, temporary supply of at least an approved month's supply of medication, or multiple fills totaling that amount if the prescription is written for less, accompanied by written notice. The transition notice instructs the member to work with their prescriber to switch to a covered formulary alternative or request a coverage determination or exception under § 423.578. Transition is not a coverage determination and does not replace remainder-of-year exemption for non-maintenance changes. For a detailed operational comparison of transition fills and commercial support mechanisms, see our analysis of Medicare Part D transition fills versus manufacturer bridge programs.

To determine whether an operational issue actually exists, the reimbursement team must monitor real-world claim adjudication. As illustrated in the following workflow, a formulary notice should trigger document classification and data verification—not premature appeal filings:

flowchart TD
  A["Formulary Change Notice Received"] --> B{"Classify Payer & Benefit"}
  B -->|"Medicare Part D"| C{"Classify Change Type"}
  B -->|"Medicare Advantage Medical"| D["Apply 42 CFR 422.138: Medical PA Binding"]
  B -->|"Commercial ERISA"| E{"Plan Amendment vs. Cutoff"}
  C -->|"Non-Maintenance Change"| F["Enrollee Exempt for Remainder of Plan Year"]
  C -->|"Maintenance Change"| G["30-Day Notice or 1-Month Refill Allowed"]
  G --> H{"Active PA or Exception on File?"}
  H -->|"Granted § 423.578 Exception"| I["Coverage Protected for Rest of Plan Year"]
  H -->|"Standard PA Active"| J["Test Next POS Claim Submission"]
  J -->|"Claim Adjudicates Paid"| K["Maintain Active Therapy; Monitor Expiration"]
  J -->|"Claim Rejects at POS"| L["Receive CMS-10147; Submit § 423.566 Determination"]
  E -->|"Plan Amendment"| M["Informational Update of Contract Terms"]
  E -->|"Early Cutoff without Amendment"| N["Trigger 29 CFR 2560.503-1 Concurrent Care ABD"]

If an established patient presents a refill and the claim processes successfully, the authorization remains fully operative in the adjudication engine. If the claim rejects with a utilization management error, the pharmacy receives CMS-10147. Only at that moment should the provider submit a formal coverage determination request under 42 CFR 423.566. And only if that request is formally denied via CMS-10146 does an appealable legal controversy exist. Navigating that subsequent step is examined in our guide to prior authorization reauthorization denial and appeal workflows and our review of renewal denials after demonstrated clinical stability.

Do Not Import MA Medical PA or Commercial ERISA Rules into a Part D Letter

A frequent cause of strategic missteps in market access is regulatory conflation: taking a consumer protection rule that applies in one payer market and asserting it as authority in another. Case managers frequently cite Medicare Advantage medical-benefit rules or federal ERISA claims regulations when drafting Part D correspondence, or vice versa. These frameworks are legally distinct and operate under completely separate statutory authorities.

Medicare Advantage Medical Prior Authorization (42 CFR 422.138 & 422.112): Under Title 42 Part 422, CMS governs Medicare Advantage (MA) organizations offering Part C coordinated care plans. Under 42 CFR 422.138(c), if an MA organization approves the furnishing of a covered medical item or service through prior authorization, pre-service determination, or concurrent review, it may not later deny coverage on the basis of lack of medical necessity, and may not reopen the determination except for good cause (under 42 CFR 405.986 and 422.616) or reliable evidence of fraud. Furthermore, under 42 CFR 422.112(b)(8)(i), for enrollees undergoing an active course of treatment, approval of a prior authorization for a course of treatment must remain valid for as long as medically necessary to avoid disruptions in care, in accordance with applicable coverage criteria, the patient's medical history, and the treating provider's recommendation. Separately, 42 CFR 422.112(b)(8)(i)(B) requires a minimum 90-day transition period when an enrollee has enrolled in an MA plan after starting a course of treatment, including enrollees new to a plan and new to Medicare, during which the MA organization must not disrupt or require reauthorization even if the service is furnished out of network. The 90-day window is a new-enrollee continuity rule; it is not a universal overlay on every in-force MA prior authorization.

These MA basic-benefit protections are powerful tools when defending provider-administered infusions, biologics, and oncology regimens billed under the medical benefit. However, they govern Medicare Part C medical benefits, not Part D outpatient pharmacy benefits. Section 422.138(c) does not rewrite Part D formulary maintenance rules under Section 423.120, and asserting that a Part D sponsor cannot adjust its drug formulary because of Section 422.138 is a category error that claims adjudicators immediately reject. For a comprehensive review of benefit routing, see our analysis of medical versus pharmacy benefit verification for specialty drugs.

ACA Essential Health Benefits (45 CFR 156.122): For individual and small-group commercial plans subject to Affordable Care Act Essential Health Benefit (EHB) requirements, 45 CFR 156.122(c) establishes a distinct exceptions architecture. A standard exception determination must be made no later than 72 hours after receipt of the request; an expedited review based on exigent circumstances must be decided within 24 hours. If a standard exception is granted, the plan must provide coverage of the non-formulary drug for the duration of the prescription, including refills. An expedited exception, if granted, must be covered for the duration of the exigency. Here again, the granted exception—not a general issuer formulary-update letter—is the coverage determination.

Commercial ERISA Group Health Plans (29 CFR 2560.503-1): In self-funded employer health plans governed by the Employee Retirement Income Security Act (ERISA), claim procedures are regulated by Department of Labor (DOL) rules. Under 29 CFR 2560.503-1(m)(4), an adverse benefit determination (ABD) encompasses any denial, reduction, or termination of, or failure to provide or make payment for, a benefit, including those resulting from utilization review. Under the concurrent-care rule at 29 CFR 2560.503-1(f)(2)(ii)(A), any reduction or termination of an approved course of treatment before the end of the approved period or number of treatments, other than by plan amendment or termination, is an ABD. The plan must notify the claimant in time to appeal and obtain a review decision before the benefit is reduced or terminated.

However, the ERISA concurrent-care rule contains an explicit exception: other than by plan amendment or termination. As confirmed in DOL subregulatory guidance, if an employer sponsor amends its overall plan terms or formulary structure mid-year, that plan amendment is not an individualized concurrent-care reduction. Terminating an approved patient authorization early without a valid plan amendment requires a formal Paragraph (g) adverse benefit determination notice. Conversely, a general formulary notice reflecting a formal plan amendment is an administrative disclosure, not an individual denial.

Commercial market access dynamics, PBM formulary updates, and state gold-carding laws further complicate this landscape. While several national payer organizations made voluntary continuity pledges in 2025 to honor existing prior authorizations for 90 days following mid-year formulary shifts, voluntary trade pledges do not constitute federal statutory mandates. Tracking state-level legislative mandates requires consulting our state prior authorization reform tracker and broader commercial positioning tools such as the payer coverage matrix for specialty drugs and our tracking of CVS Caremark formulary and GLP-1 coverage changes.

Operator Checklist, Then Stop

To eliminate administrative churn, prevent premature appeal dismissals, and safeguard patient therapy continuity, reimbursement teams and case managers should follow a disciplined six-step intake protocol whenever a formulary change notice is received:

1. Step 1: Identify the Payer Program and Benefit Channel. Determine whether the coverage is Medicare Part D, Medicare Advantage Part B (medical benefit), Medicaid Managed Care, an ACA Marketplace Qualified Health Plan, or an ERISA self-funded commercial plan. Never apply Title 42 Part 422 medical rules to a Part D pharmacy communication, and never cite ERISA regulations in a Medicare Part D redetermination.

2. Step 2: Classify the Physical Artifact in Hand. Examine the document header and statutory citations. Is it an informational Notice of Formulary Change under 42 CFR 423.120(f)? A pharmacy point-of-sale rejection notice (CMS-10147)? An Annual Notice of Change (ANOC)? Or a formal Notice of Denial of Medicare Prescription Drug Coverage (CMS-10146)? If the document is not CMS-10146 (or a commercial adverse benefit determination letter containing formal appeal filing deadlines), it is not an appealable denial.

3. Step 3: Classify the Part D Change Category. If the plan is Medicare Part D, determine whether the change is maintenance or non-maintenance under 42 CFR 423.100. If the change is non-maintenance, verify whether the patient qualifies as an affected enrollee. If the patient is currently taking the medication, verify that the sponsor is honoring the statutory mandate under 42 CFR 423.120(e)(3)(ii) exempting the member for the remainder of the contract year.

4. Step 4: Audit Existing Authorizations and Exception Records. Check the patient's internal file for an existing authorization number. Was the drug approved via a standard formulary prior authorization or a formal exception under 42 CFR 423.578? If an exception was granted, verify that the prescriber continues to prescribe and therapy remains clinically safe, confirming that coverage is legally protected under § 423.578(c) through the end of the enrollment period.

5. Step 5: Test Real-World Claim Adjudication at the Pharmacy. Do not treat an advance formulary-change notice as if it were already a denial, and do not submit speculative appeals from the notice alone. Allow the pharmacy to transmit the next scheduled refill claim. If that claim processes as paid, document the paid claim and monitor the authorization's stated expiration date. If it rejects, collect the POS rejection and CMS-10147. This article does not estimate how often an unexpired PA number still pays after a maintenance overlay.

6. Step 6: Initiate Coverage Determinations Only Upon True Denial. If the refill claim rejects at POS, collect the rejection code and CMS-10147 from the dispensing pharmacy. Then, and only then, submit a comprehensive coverage determination or exception request under 42 CFR 423.566 supported by the prescriber's statement. As interoperability rules advance, monitor technical requirements outlined in our guides to electronic prior authorization readiness for 2027, FHIR prior authorization data fields that prevent denials, and interchangeable biosimilar substitution notices.

Sources

• 42 CFR 423.100 — Definitions — Electronic Code of Federal Regulations. Establishes governing federal definitions for negative formulary changes, affected enrollees, maintenance changes, and non-maintenance changes in Medicare Part D.

• 42 CFR 423.120 — Access to covered Part D drugs — Electronic Code of Federal Regulations. Codifies requirements for negative formulary change approvals, the 30-day notice standard, remainder-of-year exemptions for non-maintenance changes, and enrollee transition fills.

• 42 CFR 423.566 — Coverage determinations — Electronic Code of Federal Regulations. Enumerates the exhaustive list of plan sponsor actions that constitute formal Part D coverage determinations.

• 42 CFR 423.568 — Standard timeframe and notice requirements for coverage determinations — Electronic Code of Federal Regulations. Defines operational timelines and written notice requirements for standard and expedited Part D coverage determinations.

• 42 CFR 423.578 — Exceptions process — Electronic Code of Federal Regulations. Governs tiering and formulary exception procedures and establishes the statutory duration of granted exceptions through the enrollment period.

• 42 CFR 422.112 — Access to services — Electronic Code of Federal Regulations. Sets forth Medicare Advantage basic-benefit access standards, active-course-of-treatment protections, and mandatory 90-day transition windows.

• 42 CFR 422.138 — Prior authorization — Electronic Code of Federal Regulations. Prohibits Medicare Advantage organizations from later denying coverage on the basis of medical necessity for approved prior authorizations.

• Medicare Program; CY 2024 Remaining Provisions and CY 2025 Policy and Technical Changes (89 FR 30448) — Federal Register. Final rule recodifying 42 CFR 423.120(e) and (f), establishing the current 30-day notice clock, maintenance deemed-approval mechanics, and non-maintenance exemptions.

• Final Calendar Year (CY) 2026 Part D Redesign Program Instructions — Centers for Medicare & Medicaid Services. Confirms the ongoing application of recodified negative formulary change and immediate substitution regulations through CY 2026.

• Plan Sponsor Notices and Other Documents — Centers for Medicare & Medicaid Services. Central repository distinguishing standardized coverage determination forms (CMS-10146, CMS-10147) from discretionary model sponsor notices.

• Form Instructions for the Notice of Denial of Medicare Prescription Drug Coverage (CMS-10146) — Centers for Medicare & Medicaid Services. Operational instructions mandating unedited completion of standardized denial notices for adverse Part D determinations.

• 45 CFR 156.122 — Prescription drug benefits — Electronic Code of Federal Regulations. Establishes Essential Health Benefit formulary exception standards, including coverage for the duration of the prescription and refills after a granted standard exception and for the duration of the exigency after a granted expedited exception.

• 29 CFR 2560.503-1 — Claims procedure — Electronic Code of Federal Regulations. Department of Labor ERISA claims regulations defining adverse benefit determinations, concurrent-care requirements, and the plan-amendment exception.

• Benefit Claims Procedure Regulation FAQs — U.S. Department of Labor Employee Benefits Security Administration. Clarifies concurrent-care reductions versus plan amendments under ERISA claims regulations.

• Medicare Prescription Drug Benefit Manual, Chapter 6 — Part D Drugs and Formulary Requirements — Centers for Medicare & Medicaid Services. Historical reference document (Rev. 18, 2016) detailing legacy 60-day notice guidelines superseded by modern 30-day regulatory amendments.