comes although, as we will show later, regimens that are more toxic are likely to be both more effective and have more severe side effects.
New colorectal cancer regimens tend to be more efficacious than the existing regimens, with side effect profiles that are sometimes more and sometimes less severe than earlier regimens. Consider the new entrant in 1996, irinotecan + 5-FU/LV (second row of Table 1). Relative to patients who received 5-FU/LV in a clinical trial (first row of Table 1), patients in clinical trials who received irinotecan + 5-FU/LV lived 3.1 months longer, on average, had a 14.6 percentage point higher probability of experiencing a reduction in the size of their tumor, and experienced a two month delay in the time it took for the cancer to advance to a more severe state. However, patients taking the new regimen were more likely to experience five of the six side effects listed in Table 1.
Oxaliplatin + 5-FU/LV, which was launched in 2002 (fifth row of Table 1), is more efficacious and has fewer severe side effects than irinotecan + 5-FU/LV. Patients in clinical trials of the former regimen lived an average of 3.8 months longer, had a 10.7 percentage point higher probability of experiencing a reduction in the size of their tumor, and experienced a 2.4 month delay in the time it took for the cancer to advance to a more severe stage relative to the latter regimen. Oxaliplatin + 5-FU/LV patients are also less likely to experience a grade 3 or 4 side effect for five of the six measures relative to irinotecan + 5-FU/LV. Finally, the arrival of bevacizumab + oxaliplatin + 5-FU in 2004 increased the median survival time by about four months relative to oxaliplatin + 5-FU/LV, with sub- stantial improvements on three side effect measures and worse performance on the other three side effect measures.
Two new second-line regimens entered the market in 2004 to compete against the first second-line regimen (irinotecan) that was launched in 1996.17 Cetuximab
irinotecan has a substantially better response rate than irinotecan administered
17Regimens that include the tablet, capecitabine, are chemically equivalent to regimens that include 5- FU/LV.