Atorvastatin Is More Cost-Effective than Rosuvastatin or Simvastatin/Ezetimibe

Anaheim—An analysis of 3-year patient drug costs for branded statin therapies found that patients taking atorvastatin were less costly for managed care health plans to cover than patients taking rosuvastatin or a combination of simvastatin and ezetimibe. The 3-year net present cost for patients taking atorvastatin under a tier 3 nonpreferred formulary status was $774 compared with $1455 for rosuvastatin and $1159 for simvastatin and ezetimibe. For a tier 2 preferred formulary status, the 3-year cost was $746 for atorvastatin, $1345 for rosuvastatin, and $1109 for simvastatin and ezetimibe. All costs were reported in 2010 US dollars. The results were presented at the ASHP meeting during a poster presentation titled Net Present Cost of Branded Statin Therapy over Three Years. Andreas Kuznick and Larry Liu, the poster’s authors, are employees of Pfizer, Inc, which manufactures atorvastatin and funded the study. According to the authors, health plans spend a significant portion of their pharmacy benefit on branded statin therapies, although most states allow or mandate that patients can substitute generic drugs for brand drugs at the pharmacy level except when the prescribing physician requests the brand drug. In their analysis, the authors developed a model to determine the 3-year net present cost for a hypothetical patient who initiated therapy on atorvastatin, rosuvastatin, or simvastatin and ezetimibe beginning in December 2010. To calculate the costs, they used published studies, administrative claims data, and assumptions based on historical trends. The costs were based on the daily wholesale acquisition cost (WAC) for each drug: $3.66 for atorvastatin, $3.89 for rosuvastatin, and $3.55 for simvastatin/ezetimibe. The authors said they used wholesale costs to avoid regional price differences. They applied a 3% annual discount rate to each drug plus a 50% discount off atorvastatin’s current WAC for the first 6 months after the drug loses exclusivity on November 30, 2011, followed by generic pricing of $0.50 per day for the remaining months. In addition, the authors hypothesized that there was a 2% per month probability that patients would switch from rosuvastatin or simvastatin/ezetimibe to a generic version of atorvastatin when it becomes available. The model also included historical adherence rates for the therapies. The authors assumed the base case was similar to a tier 3 formulary status and assumed no rebates and a $45 copayment per script for branded statins and a $10 copayment for generic atorvastatin. In addition, they undertook a sensitivity analysis to evaluate how tier 2 pricing would affect the drugs and included a 20% rebate and a $25 copayment for the branded statins. They also performed a breakeven analysis to assess the increases in rebates and the probability patients would switch to generic atorvastatin to make the net present cost equal for all 3 statins. The authors found that for the 3 therapies to have a similar net present cost, a rosuvastatin rebate must increase to 48% and a simvastatin/ezetimibe rebate must increase to 40%. In addition, to equalize the net present cost, the monthly probability of switching to generic atorvastatin must increase from 2% to 28%. The authors concluded that the main component of the cost-savings comes from the ability of patients to easily switch from branded atorvastatin to generic atorvastatin when the drug loses exclusivity. Patients will have more difficulty switching from the other 2 statins to generic atorvastatin, the authors said.