Effect of a Therapeutic Maximum Allowable Cost (MAC) Program on the Cost and Utilization of Proton Pump Inhibitors in an Employer-Sponsored Drug Plan in Canada

BACKGROUND: Therapeutic maximum allowable cost (MAC) is a managed care intervention that uses reference pricing in a therapeutic class or category of drugs or an indication (e.g., heartburn). Therapeutic MAC has not been studied in Canada or the United States. The proton pump inhibitor (PPI) rabeprazole was used as the reference drug in this therapeutic MAC program based on prices for PPIs in the province of Ontario. No PPI is available over the counter in Canada. OBJECTIVES: To evaluate the utilization and anticipated drug cost savings for PPIs in an employer-sponsored drug plan in Canada that implemented a therapeutic MAC program for PPIs. METHODS: An employer group with an average of 6,300 covered members, which adopted the MAC program for PPIs in June 2003, was compared with a comparison group comprising the book of business throughout Canada (approximately 5 million lives) without a PPI MAC program (non-MAC group). Pharmacy claims for PPIs were identified using the first 6 characters of the generic product identifier (GPI 492700) for a 36-month period from June 1, 2002, through May 31, 2005. The primary comparison was the year prior to the intervention (from June 1, 2002, through May 31, 2003) and the first full year following the intervention (June 1, 2004, through May 31, 2005). Drug utilization was evaluated by comparing the market share of each of the PPIs for the 2 time periods and by the days of PPI therapy per patient per year (PPPY) and days of therapy per prescription (Rx). Drug cost was defined as the cost of the drug (ingredient cost), including allowable provincial pharmacy markup but excluding pharmacy dispense fee. Cost savings were calculated from the allowed drug cost per claim, allowed cost per day, and allowed cost PPPY. RESULTS: (All amounts are in Canadian dollars.) The MAC intervention group experienced an 11.7% reduction in the average cost per day of PPI drug therapy, from $2.14 in the preperiod to $1.89 in the postperiod, compared with a 3.7% reduction in the comparison group ($2.16 vs. $2.08). Utilization dropped by 11.9% in the intervention group, from 166.7 days of PPI drug therapy PPPY to 146.9 days PPPY, compared with an increase of 7.9% in the comparison group, from 136.1 days to 146.8 days PPPY. The combined effect of the decrease in drug cost per day and utilization was a 22.1% reduction in allowed drug cost PPPY in the intervention (MAC) group (from $357 to $278 PPPY) versus a 4.1% increase in the comparison group (from $293 to $305 PPPY). CONCLUSIONS: A MAC program for PPIs for one employer in Canada was associated with savings for the drug plan sponsor of approximately 8% in actual drug cost per day of therapy compared with the comparison group. Total savings after consideration of utilization was approximately 26% for the intervention group versus the comparison group.