Medicare drug plans would keep negotiated drugs on formularies

For people in Medicare’s Part D drug coverage, the practical question is simple: can a negotiated medicine disappear from the plan list just because the price changed? The Centers for Medicare & Medicaid Services, or CMS, is proposing to say no. When a selected drug has a maximum fair price, or MFP, in effect, Part D sponsors would have to keep it on their formularies, the lists that decide what a plan covers. The agency says the rule would apply for 2029 and later, which matters because coverage is where a price cut becomes real for patients at the pharmacy counter.

That is the part beneficiaries notice first. If a drug stays on the formulary, a patient, prescriber and pharmacist are not left chasing a separate workaround after Medicare negotiates the price. The change is meant to keep coverage tied to the drug itself, not just to the price CMS has set for it.

Coverage stays with the drug

CMS is proposing to write the rule into 42 CFR 423.120(b)(2)(vii) and (viii), folding it into the broader Medicare drug price negotiation program and the Medicare Prescription Drug Benefit Program, better known as Part D. That makes the requirement explicit: once an MFP is in effect, selected drugs generally stay on plan formularies. The agency is not leaving the point to guesswork or informal guidance.

The narrow exit

The proposal is not absolute. CMS would keep a narrow immediate-substitution exception, allowing a plan to remove a selected drug if another drug can be substituted right away. That is a limited escape hatch, not a free pass to reshuffle coverage. For manufacturers, the formulary decision still matters because it affects whether patients can reach the product through Medicare. For patients managing ongoing treatment, the value of the negotiated price depends on whether the drug remains in front of them when they fill a prescription.