Analyzing the Impact of the FDA Oncologic Drug Advisory Committee Decision on Continued Utilization of Avastin for the Treatment of Metastatic Breast Cancer Open Access

Koris, Caitlin Marie (2015)

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Objectives Breast cancer is the second most common cause of cancer-related death. Women with metastatic disease have low survival rate due in part to the lack of effective treatments. In 2008, the U.S. Food and Drug Administration (FDA) granted an accelerated approval of Avastin to treat metastatic breast cancer (MBC) in combination with paclitaxel. In July 2010, the Oncologic Drug Advisory Committee (ODAC) voted unanimously to withdraw the approval. This decision was contested by many including the European Medicine Agency (EMA) and the National Comprehensive Cancer Network (NCCN). Despite this disagreement, the FDA revoked the approval by the end of 2011. This study examined the impact of ODAC's decision on prescribing practices. Methods Truven MarketScan claims data from 2006 - 2011 was used as the data source. The sample included women 18 years or older who received specific chemotherapy agent listed in the NCCN treatment guidelines for MBC. A difference-in-difference model compared Avastin use before/after the 2010 ODAC decision using colorectal cancer to form the control group. Results Providers were about 41% (a<0.001) less likely to prescribe Avastin after 2010. Region impacted this associated. Prescribers in North central, South and West were approximately 3.3 - 10.0% (a>0.001) more likely to prescribe Avastin than prescribers in the Northeast. Conclusion The magnitude of the utilization decrease in 2011 is higher than expected. However, we speculate that conflicting information on Avastin's effectiveness led to greater reliance on the ODAC decision by providers. Only one other study has examined the impact of ODAC and our results are consistent with their findings. The impact of region on prescribing practices may be due to the high concentration of academic medical centers in the North east. The FDA needs to fully understand the impact of their advisory bodies on influencing providers when considering public health needs.

Table of Contents


History of Avastin. 2

Clinical Trials. 4

Impact of Cost. 5


Technology Diffusion. 6

Impact of FDA Regulations/Policies. 7


Conceptual Model. 9

Study Sample Identification. 10

Coding in Claims Data. 13

Variables. 13

Research Question. 15

Hypothesis. 15

Research Design. 15

Data Analysis. 15

Sensitivity Analysis. 16



Summary. 22

Conclusion. 22

Limitations. 23

Recommendations for Future Studies. 24

Policy Implications. 24



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