The FDA's assessment of follow-on protein products: a historical perspective.

The scientific and regulatory issues that are associated with the possible introduction of 'follow-on' versions of protein drug products are the topic of considerable debate at present. Because of the differences between protein drug products and small-molecule drugs, the development of follow-on versions of protein products presents more complex scientific challenges than those presented by the development of generic versions of small-molecule drugs. Here, with a view to illustrating the Food and Drug Administration's (FDA's) scientific reasoning and experience in this area, we discuss past examples of the FDA's actions involving the evaluation of various types of follow-on and second-generation protein products and within-product manufacturing changes. The FDA believes its evaluation of the safety and effectiveness of follow-on protein products will evolve as scientific and technological advances in product characterization and manufacturing continue to reduce some of the complexity and uncertainty that are inherent in the manufacturing of protein products.

Pediatric drug labeling: improving the safety and efficacy of pediatric therapies.

CONTEXT: Approximately 50% to 75% of drugs used in pediatric medicine have not been studied adequately to provide appropriate labeling information. In 1997, Congress passed the Food and Drug Administration Modernization Act (FDAMA), which encouraged pediatric drug development by providing an incentive in the form of additional marketing exclusivity. OBJECTIVE: To identify new drug labeling information from pediatric studies submitted to the FDA in response to written requests. DESIGN AND SETTING: Between July 1998 and April 1, 2002, the FDA requested studies on 242 drugs, and 53 drugs were granted exclusivity. As of January 2003, 49 drugs have new labels. Data from the studies of the first 33 drugs with new pediatric information on the label as of April 2002 are included. Significant labeling information was analyzed along with baseline data and types of studies requested. MAIN OUTCOME MEASURES: Safety data and pediatric information for labeled drugs. RESULTS: There were 53 studies for 33 drug products, 12 (23%) were evaluated for safety only; 23 (43%), safety and efficacy; and 18 (34%), pharmacokinetics and/or pharmacodynamics. Significant new dosing and/or safety information was identified for 12 (36%) drugs. New dosing information was determined for 7 of these drugs. Safety information was defined for gabapentin, propofol, sevoflurane, the combination of ribavirin and interferon alfa-2b, and various betamethasone-containing dermatologic preparations. There was a higher percentage of deaths reported with patients who received propofol compared with controls in the pediatric intensive care unit. Seizures were seen in patients administered sevoflurane. Patients receiving a combination of ribavirin and interferon alfa-2b experienced an increased incidence of suicidal ideation when compared with adults. An unexpectedly high percentage of those receiving betamethasone-containing dermatologic preparations had documented hypopituitary-adrenal axis suppression. CONCLUSION: The FDAMA has stimulated pediatric clinical studies resulting in improved understanding of the pharmacokinetics of drugs prescribed in pediatric medicine, important dose changes, and improved safety for children taking certain drugs.

Improving pediatric dosing through pediatric initiatives: what we have learned.

OBJECTIVE: The goal was to review the impact of pediatric drug studies, as measured by the improvement in pediatric dosing and other pertinent information captured in the drug labeling. METHODS: We reviewed the pediatric studies for 108 products submitted (July 1998 through October 2005) in response to a Food and Drug Administration written request for pediatric studies, and the subsequent labeling changes. We analyzed the dosing modifications and focused on drug clearance as an important parameter influencing pediatric dosing. RESULTS: The first 108 drugs with new or revised pediatric labeling changes had dosing changes or pharmacokinetic information (n = 23), new safety information (n = 34), information concerning lack of efficacy (n = 19), new pediatric formulations (n = 12), and extended age limits (n = 77). A product might have had > or = 1 labeling change. We selected specific examples (n = 16) that illustrate significant differences in pediatric pharmacokinetics. CONCLUSIONS: Critical changes in drug labeling for pediatric patients illustrate that unique pediatric dosing often is necessary, reflecting growth and maturational stages of pediatric patients. These changes provide evidence that pediatric dosing should not be determined by simply applying weight-based calculations to the adult dose. Drug clearance is highly variable in the pediatric population and is not readily predictable on the basis of adult information.