Employing mandatory 90day supply requirements for oral chemotherapy agents leads to drug waste and increased costs, and a shorterterm (30day) supply should be considered for these agents, according to a pharmacy claims database analysis.
Researchers from Prime Therapeutics examined a database of 5.7 million members from 3 Blue Cross Blue Shield plans from the Midwest and South, and extracted claims for erlotinib and imatinib between 2006 and 2010. Members were tracked by the amount of time they spent under the insurance plan; the amount of erlotinib or imatinib supplied to members during their time in the plan was also tracked. Waste was calculated as the difference between the member’s total days of supply of the drugs and the number of days in the plan. Projected waste was then calculated if members had been given 30day supplies instead.
During the study period, the wholesale acquisition costs for erlotinib and imatinib increased anywhere from 26.7% (for imatinib 100mg tablets) to 57.8% (for imatinib 400mg tablets). Seventy of 418 members had at least 1 fill with a 90day supply; 19 of the 418 members had actual waste (estimated to cost $23,952). Calculating projected waste, the authors determined that more than 11,700 days of waste would have occurred if 90day supplies were used instead of 30day supplies. This excess waste totaled $1,433,723. The range of average excess supply per member was 34 days to 56 days (for 90day supplies) and 13 days to 16 days (for 30day supplies).
The authors caution that actual waste cannot be definitively known because of dosing changes and the estimation of time that members were in the plans. A further limitation is the small sample size (418 members of the total 5.7 million) in the plan.