To amend part D of title XVIII of the Social Security Act to extend the 2006 and 2007 initial enrollment periods for the Medicare prescription drug benefit and suspend the late enrollment penalty through December 31, 2007, to permit Medicare beneficiaries to change enrollment in a prescription drug plan during the first 12 months of enrollment, and to prevent changes in formularies other than at the time of open enrollment periods and only with advance notice.

Amends part D (Voluntary Prescription Drug Benefit Program) of title XVIII (Medicare) of the Social Security Act to: (1) extend the 2006 and 2007 initial enrollment periods for the Medicare prescription drug benefit; (2) suspend the late enrollment penalty through December 31, 2007; and (3) permit Medicare beneficiaries to change enrollment in a prescription drug plan during the first 12 months of enrollment.

Prohibits a PDP sponsor, beginning with 2006, from removing a covered part D drug from the plan formulary, or imposing a restriction or limitation on the coverage of such a drug, other than at the beginning of each plan year, except as the Secretary may permit to take into account new therapeutic uses and newly covered part D drugs.

Requires each PDP sponsor to furnish to each plan enrollee, at the time of each annual coordinated election period, a notice of any changes in the formulary or other part D drug coverage restrictions or limitations that will take effect for the upcoming plan year.