The OIG has issued a report on Midyear Formulary Changes in Medicare Prescription Drug Plans, which concludes that Part D drug plan sponsors and CMS are managing midyear formulary changes without major problems.  The OIG found that all drug plan sponsors made formulary changes in 2008, but the majority (64%) of these changes were positive (i.e., they added new drugs, reduced cost sharing, or removed utilization controls).  Of the changes that were more restrictive (which must be approved by CMS), 62% promoted generic drug substitution. According to the OIG, most plan sponsors met beneficiary notification requirements for formulary changes.