that the samples used by IntrinsiQ and/or SEER may not be consistent.14In order to smooth market shares between the pre- and post-2002 periods, we apply a regimen-specific factor to adjust the pre-2002 market shares based on the ratio of total (from IntrinsiQ) to Medicare-only (from SEER) market shares for the four quarters of 2002, when the two data sets overlap.
In order to calculate the price per regimen, we require information on the quantity of each drug in a regimen. The National Comprehensive Cancer Network (NCCN) reports the typical amount of active ingredient used by physicians for the major regimens. We supplement this where necessary with dosage information from drug package inserts, conference abstracts, and journal articles. Dosage information is reported in Appendix 1. For example, the standard dosage schedule for the regimen with the second largest market share in 2005 is 85 milligrams (mg) of oxaliplatin per meter squared of a patient’s surface area infused by IV on the first day of treatment, followed by a 1,000 mg infusion of 5-FU per meter squared of surface area on the first and second treatment days, and a 200 mg infusion of leucovorin per meter squared on the first and second treatment days. This process is repeated every two weeks. We price the regimens for a representative patient who has 1.7 meters squared of surface area (Jacobson et al., 2006) weighs 80 kilograms, and is treated for 24 weeks. Regimen prices are derived by multiplying the average price a customer paid per milligram of active ingredient in a quarter by the recommended dosage amounts for each drug in the regimen over a 24-week period.15
We obtain most of the attribute information for each regimen from the FDA- approved package inserts that accompany each drug. These inserts describe the phase 3 clinical trials that were conducted, including the number and types of patients enrolled in the trials, the health outcomes for patients in the treatment and control groups, and the side effects experienced by those patients. Often there
The SEER sample is drawn from locations representing 26 percent of the U.S. population. The regimens are priced used price data for the contemporaneous quarter only.