OBJECTIVES: Medicare Part D specialty drug users who do not qualify for low-income subsidies (non-LIS beneficiaries) face high and variable cost sharing during the calendar year. We examined their out-of-pocket (OOP) cost patterns under the existing Part D cost-sharing policies and under proposed changes to these policies. METHODS: Using 2012 100% Medicare claims data, we examined mean annual and monthly OOP drug costs for Medicare Part D patients who were full-year users of Part D specialty drugs for rheumatoid arthritis (RA, n=1,063), multiple sclerosis (MS, n=2,256), or chronic myeloid leukemia (CML, n=1,135) under existing policy. Using the same data, we simulated costs under both proposed MedPAC policy recommendations and our own recommendations. RESULTS: In 2012, our sample faced mean annual cumulative OOP drug costs (for all medications) of $3,949 (RA), $5,238 (MS), and $6,322 (CML). Mean OOP costs were $977 (RA), $1,613 (MS), and $2,456 (CML) in January alone. A substantial proportion of total annual OOP prescription spending also occurred during the catastrophic coverage phase (RA=$1,229 [31%], MS=$2,456 [47%], CML=$3,546 [56%]. Under proposed MedPAC changes, patients would have faced maximum annual OOP spending of $4,700, but mean OOP costs in January and February would have been higher compared to existing policy. Under our proposed strategy, OOP costs would have been spread evenly over 12 months (≤$392 per month). The potential incremental costs of our proposed strategy would have been $23.55 per non-LIS Part D beneficiary per year. CONCLUSIONS: The existing Part D cost-sharing structure creates substantial financial burden for specialty drug users, especially early in the year. Implementing both annual and monthly OOP maximum spending limits would result in lower, more consistent OOP costs, potentially increasing patients’ ability to access treatments for life-threatening, chronic, and rare diseases.