Background: Erythropoietin-stimulating agents (ESAs) have been used to treat chemotherapy-related anemia in cancer patients since 1993. Erythropoietin-stimulating agents are a useful substitute for blood transfusions for these patients; however, there were unacknowledged toxicities for ESAs when they were first administered. One such toxicity is venous thromboembolisms (VTEs). In March 2007, these toxicities were acknowledged by the FDA when a black box warning was issued for ESAs. This study aimed to observe ESA utilization trends along with VTE and transfusion rates to determine the effect of the black box warning
Methods: The 2002 to 2010 merged South Carolina Medicaid-Cancer Registry dataset was used to determine the effect of the FDA black box warning. Patients with breast, non-small cell lung, and colorectal cancer who were over 18 were determined from the cancer registry. Of these, chemotherapy users were identified. From the chemotherapy population, ESA users were identified from medical and pharmacy claims. The final sample contained those who had their first ESA claim after chemotherapy and not dual enrolled in Medicare. Qualitative analysis was done for trends, and logistic regression was used as a quantitative measure.
Results: Of the 3,689 cancer patients with chemotherapy, 1,315 (36%) had at least 1 ESA claim. The maximum rate of ESA patients was seen in 2006 (56%) followed by a decline to 43% in 2008 and 11% in 2010. Logistic regression showed a 78% reduction in the odds of receiving an ESA after the black box warning compared with before. Venous thromboembolism rates in ESA users declined from 0.6% in 2002 to 0.4% in 2009 and 2010. There is a 45% reduction in the odds of getting a VTE after the black box warning adjusting for clinical and demographic characteristics. Transfusion rates in ESA users increased from 0.2% in 2002 to 0.3% in 2009 and 2010. There is a 96% increase in the odds of getting a transfusion after the black box warning adjusting for clinical and demographic characteristics.
Conclusions: The decline of ESA use and VTE rates and an increase in transfusions look to be related to the black box warning.
