The impact of the written request process on drug development in childhood cancer

The Food and Drug Administration (FDA) Modernization Act, enacted in 1997, created a pediatric exclusivity incentive allowing sponsors to qualify for an additional 6 months of marketing exclusivity after satisfying the requirements outlined in the Written Request (WR). This review evaluates the impact of the WR mechanism on the development of oncology drugs in children.

A search of the FDA document archiving, reporting, and regulatory tracking system was performed for January 1, 2000 to December 31, 2010. Drugs were identified and pediatric-specific labeling information was obtained from Drugs@fda.gov and FDA Pediatric Labeling Changes Table.

Fifty WRs have been issued for oncology drugs. Pediatric studies have been submitted for 14 drugs. Thirteen received pediatric exclusivity. As of December 31, 2010, labeling changes have been made for 11 drugs. Three drugs were approved for pediatric use.

WRs have provided a mechanism to promote the study of drugs in pediatric malignancies. Information from studies resulting from the WRs regarding safety, pharmacokinetics, and tolerability of oncology drugs has been incorporated into pediatric labeling for 11/14 of the drugs. Earlier communication and collaboration between the FDA, National Cancer Institute, clinical investigators, and commercial sponsors are envisioned to facilitate the identification and prioritization of emerging new drugs of interest for WR consideration. Since this is the only regulatory mechanism, resulting from specific legislative initiatives relevant to cancer drug development for children, efforts to enhance its impact on increasing drug approval for pediatric cancer indications are warranted.