The Centers for Medicare & Medicaid Services said it may consider limiting the number of plans that insurers can offer under the Medicare prescription drug benefit next year.

Insurers with Medicare drug plans may be limited to offering one “basic” benefit plan and one “enhanced” benefit plan in each region, according to a recent letter to insurers from the agency. This year insurers were allowed to sponsor up to three plans per region.

CMS also said in the letter it is considering changing the effective dates of enrollment so that beneficiaries who sign up near the end of the month would not expect to begin coverage on the first day of the following month. The letter asks for insurers to provide feedback to CMS by March 1.