How Medicare Open Enrollment Works Before December 7, and the 2027 Drug Cap

Medicare’s Open Enrollment Period is open now. It runs from October 15 to December 7 each year. Changes made in the window take effect on January 1, and the enrollment request must reach the plan by December 7.

The window covers Medicare Advantage plans, standalone drug plans and moves between Original Medicare and Medicare Advantage. It also covers adding or dropping prescription drug coverage. This explainer sets out those rules and the 2027 spending limits for Part D, the Medicare prescription drug benefit.

Who Can Make Changes in the Window

During Open Enrollment, people in a Medicare Advantage plan can join, drop or switch plans, with or without drug coverage, and can add or drop drug coverage. People in Original Medicare can join, drop or switch standalone Medicare drug plans. People can also move from Original Medicare to Medicare Advantage, or from Medicare Advantage back to Original Medicare.

NCOA says the Medicare Open Enrollment Period is open to anyone enrolled in Medicare Part A, Part B or both, including people already in a Medicare Advantage or Part D plan. Making changes is optional.

A choice made in the window applies to the coming year, not the rest of the current one. Changes take effect January 1 of the following year, so the window sets coverage for the next calendar year. Medicare.gov’s Open Enrollment page links to Find plans and Compare coverage options tools for comparing choices.

Enrollment Window
Medicare’s Open Enrollment Period runs from October 15 to December 7 each year, and changes made in it take effect January 1, according to Medicare.gov.

Medicare Advantage Open Enrollment, January to March

According to NCOA, a separate Medicare Advantage Open Enrollment Period runs from January 1 to March 31. It is open to people already enrolled in a private Medicare Advantage plan, with or without drug coverage.

During this period, enrollees can switch to another Medicare Advantage plan. They can also drop their Medicare Advantage plan, return to Original Medicare and join a standalone drug plan. Changes take effect the first day of the month after the request is made.

NCOA says a move from Original Medicare into Medicare Advantage is possible during Medicare Open Enrollment, not during this period. People in Original Medicare cannot join, switch or change a drug plan during this period.

Switching Drug Plans and Moving to Original Medicare

When a new drug plan or a Medicare Advantage plan with drug coverage starts, the old drug coverage ends at that same point. Medicare.gov says the new plan sends a letter with the start date, so a person does not need to cancel the old plan separately.

A move to Original Medicare may require a separate drug plan. Medigap, which helps cover out-of-pocket costs, may also be wanted with Original Medicare. Medicare.gov says there are limits on when Medigap can be added, and its Open Enrollment page links to a tool for checking whether Medigap coverage is available.

Changes can be made by calling 1-800-MEDICARE (1-800-633-4227). TTY users can call 1-877-486-2048.

Dropping Drug Coverage and Restarting It Later

Drug coverage can be dropped in three situations. The first is the October 15 to December 7 window, when the change takes effect on January 1. The second is the Medicare Advantage Open Enrollment Period, which is open to people in a Medicare Advantage plan with drug coverage. The third applies when a person meets certain other circumstances.

During Open Enrollment, a person can disenroll from a Medicare drug plan by calling 1-800-MEDICARE, by mailing or faxing a signed written notice to the plan, or online if the plan offers that option. A person can also ask the plan to send a disenrollment notice, then complete, sign and return it.

Restarting drug coverage later can carry a cost. Medicare.gov says a person who goes 63 days or more in a row without other creditable prescription drug coverage must wait for an enrollment period to sign up again and may owe a late enrollment penalty.

Every change made in the window takes effect on January 1, and the enrollment request must reach the plan by December 7.

The 2027 Cap on Part D Drug Spending

CMS issued the final rule for contract year 2027 on April 2, 2026. Its fact sheet describes a reduced annual out-of-pocket threshold for Part D, eliminates the coverage gap phase and removes cost sharing for enrollees in the catastrophic phase.

The fact sheet also describes changes to true out-of-pocket cost calculations, specialty-tier rules, reinsurance payment methodologies and the Selected Drug Subsidy. It says CMS is implementing the Selected Drug Subsidy.

The fact sheet says the rule incorporates the Manufacturer Discount Program, which replaced the Coverage Gap Discount Program on January 1, 2025.

The sources differ on the threshold’s direction and amount. CURE reports $2,400 for 2027, up from $2,100 in 2026, and says CMS set the 2027 figures in April 2026. The CMS fact sheet describes the threshold as reduced and gives no dollar figure.

CURE also reports that the highest deductible a drug plan can charge rises from $615 in 2026 to $700 in 2027.

Cancer Drug Prices and Key Dates for 2027

According to CURE, Medicare-negotiated prices begin on January 1, 2027, for four drugs. They are Xtandi (enzalutamide) for prostate cancer, Pomalyst (pomalidomide) for multiple myeloma and Kaposi sarcoma, Ibrance (palbociclib) for breast cancer, and Calquence (acalabrutinib) for chronic lymphocytic leukemia and mantle cell lymphoma. CURE says CMS published the negotiated prices for the 2027 initial price applicability year in November 2025.

CURE also lists 2026 dates for the 2027 cycle. CMS announced the 2027 Medicare Advantage capitation rates and Part C and D payment policies on April 6, 2026. CMS released Part D national average bid amount information on July 28, 2026.

October 15 is the first day of the window. December 7 is the last day a plan can receive an enrollment request. Changes made in the window take effect January 1, 2027, the start of the year covered by the 2027 Part D figures above.