This final rule implements the provisions of the Social Security Act (the Act) establishing and regulating the Medicare Prescription Drug Benefit. The new voluntary prescription drug benefit program was enacted into law on December 8, 2003 in section 101 of Title I of the Medicare Prescription Drug, Improvement, and Modernization Act of 2003 (MMA) (Pub. L. 108-173). Although this final rule specifies most of the requirements for implementing the new prescription drug program, readers should note that we are also issuing a closely related rule that concerns Medicare Advantage organizations, which, if they offer coordinated care plans, must offer at least one plan that combines medical coverage under Parts A and B with prescription drug coverage. Readers should also note that separate CMS guidance on many operational details appears or will soon appear on the CMS website, such as materials on formulary review criteria, risk plan and fallback plan solicitations, bid instructions, solvency standards and pricing tools, plan benefit packages. The addition of a prescription drug benefit to Medicare represents a landmark change to the Medicare program that will significantly improve the health care coverage available to millions of Medicare beneficiaries. The MMA specifies that the prescription drug benefit program will become available to beneficiaries beginning on January 1, 2006. Generally, coverage for the prescription drug benefit will be provided under private prescription drug plans (PDPs), which will offer only prescription drug coverage, or through Medicare Advantage prescription drug plans (MA PDs), which will offer prescription drug coverage that is integrated with the health care coverage they provide to Medicare beneficiaries under Part C of Medicare. PDPs must offer a basic prescription drug benefit. MA-PDs must offer either a basic benefit or broader coverage for no additional cost. If this required level of coverage is offered, MA-PDs or PDPs, but not fallback PDPs may also offer supplemental benefits through enhanced alternative coverage for an additional premium. All organizations offering drug plans will have flexibility in the design of the prescription drug benefit. Consistent with the MMA, this final rule also provides for subsidy payments to sponsors of qualified retiree prescription drug plans to encourage retention of employer-sponsored benefits. We are implementing the drug benefit in a way that permits and encourages a range of options for Medicare beneficiaries to augment the standard Medicare coverage. These options include facilitating additional coverage through employer plans, MA-PD plans and high-option PDPs, and through charity organizations and State pharmaceutical assistance programs. See sections II.C, II.J, and II.P, and II.R of this preamble for further details on these issues. The proposed rule identified options and alternatives to the provisions we proposed and we strongly encouraged comments and ideas on our approach and on alternatives to help us design the Medicare Prescription Drug Benefit Program to operate as effectively and efficiently as possible in meeting the needs of Medicare beneficiaries.