On January 16, 2009, CMS published an interim final rule with comment period to implement MIPPA provisions regarding protected classes of drugs under the Medicare Part D prescription drug benefit. For 2010, CMS is continuing to require Part D sponsors to include all or substantially all Part D drugs in the antidepressant, antipsychotic, anticonvulsant, immunosuppressant, antiretroviral, and antineoplastic classes for 2010. For contract years 2011 and beyond, any CMS modifications to the protected categories and classes will be made through rulemaking. CMS notes that to identify appropriate drug categories and classes for future revisions, it is beginning an extensive examination of widely-used drug treatment guidelines, analyzing Part D data, and planning validation review with input from an expert panel of physicians and pharmacists. The rule is effective January 16, 2009, and comments will be accepted until March 17, 2009.