The FDA's Final Rule on Expedited Safety Reporting: Statistical Considerations.

In March 2011, a Final Rule for expedited reporting of serious adverse events took effect in the United States for studies conducted under an Investigational New Drug (IND) application. In December 2012, the U.S. Food and Drug Administration (FDA) promulgated a final Guidance describing the operationalization of this Final Rule. The Rule and Guidance clarified that a clinical trial sponsor should have evidence suggesting causality before defining an unexpected serious adverse event as a suspected adverse reaction that would require expedited reporting to the FDA. The Rule's emphasis on the need for evidence suggestive of a causal relation should lead to fewer events being reported but, among those reported, a higher percentage actually being caused by the product being tested. This article reviews the practices that were common before the Final Rule was issued and the approach the New Rule specifies. It then discusses methods for operationalizing the Final Rule with particular focus on relevant statistical considerations. It concludes with a set of recommendations addressed to Sponsors and to the FDA in implementing the Final Rule.

Phase I/II randomized trial evaluating the safety and clinical effects of repifermin administered to reduce mucositis in patients undergoing autologous hematopoietic stem cell transplantation.

PURPOSE: To evaluate the safety of repifermin (keratinocyte growth factor-2) administered before and after autologous hematopoietic stem cell transplantation (auto-HSCT). A preliminary analysis of the ability of keratinocyte growth factor-2 to prevent mucositis was also done. EXPERIMENTAL DESIGN: Forty-two patients received intravenous repifermin (25 microg/kg or 50 microg/kg) or placebo for 3 days before their auto-HSCT conditioning regimen and for up to 10 days after auto-HSCT. Within each dose level, 14 patients were randomized to repifermin and 7 patients to placebo. Clinical evaluations of mucositis were scheduled before auto-HSCT conditioning regimen, on the day of transplant, and three times per week until mucositis resolved. RESULTS: In general, the incidence of adverse events was similar for patients treated with repifermin and placebo. No clinically meaningful differences were noted among treatment groups for clinical laboratory variables. Treatment groups experienced similar time to engraftment. The frequency of Grade 2 to 4 mucositis was 100% for patients in the placebo group, 64% for patients in the 25 microg/kg group (P = 0.041 versus placebo), and 50% for patients in the 50 microg/kg group (P = 0.006 versus placebo). Results of other endpoints, including pain on swallowing and use of pain medication specifically for mucositis, suggested a better outcome for patients in the 50 microg/kg group compared with the placebo and 25 microg/kg groups. CONCLUSIONS: Repifermin was well tolerated. Repifermin given before and after auto-HSCT seems to be active in reducing mucositis, but a larger trial will be necessary to determine the efficacy of repifermin with this dose schedule.

Pharmacologic and pharmacokinetic profile of repifermin (KGF-2) in monkeys and comparative pharmacokinetics in humans.

Repifermin (truncated, recombinant human keratinocyte growth factor-2, KGF-2) was evaluated in cynomolgus monkeys and healthy humans during a phase 1 trial. Monkeys received vehicle or repifermin at 20, 75, or 200 microg/kg IV or 750 microg/kg subcutaneous (SC) daily for 29 days. Clinical observations were made during the entire dosing period. Gross and microscopic changes were assessed at necropsy. Pharmacokinetic parameters and immunogenicity were evaluated in these monkeys and in humans, following a single or 7 daily IV bolus injections of 1, 5, 25, or 50 microg/kg repifermin. In monkeys, repifermin was well tolerated, and histologic evaluation demonstrated dose-dependent, reversible thickening of the mucosa throughout the alimentary tract, except for the stomach. In the alimentary tract tissues, nonepithelial tissues were not affected, indicating a specificity of repifermin for epithelial cells. Pharmacokinetics in both monkeys and humans were dose proportional, showed lack of drug accumulation with repeated daily dosing, and were characterized by high volumes of distribution and clearance rates, indicating substantial tissue binding and metabolism. Repifermin was not markedly immunogenic following multiple daily IV injections in either species. Serum repifermin concentrations in humans were comparable to those attained in monkeys that produced significant pharmacological effects on epithelial cells in the alimentary tract. These findings provide additional support for the ongoing clinical development of repifermin for diseases involving epithelial injury.