Extrapolation of Adult Efficacy Data to Pediatric Systemic Lupus Erythematosus: Evaluating Similarities in Exposure-Response

To streamline drug development, the United States Food and Drug Administration (FDA) can consider the extrapolation of adult efficacy data to children when the disease and drug effects are sufficiently similar. This study explored whether the relationship between drug exposure and response for selected drugs in systemic lupus erythematosus (SLE) was sufficiently similar to support a consideration of the extrapolation of adult efficacy data to children of ≥5 years of age. An exposure-response analysis of drugs used to treat SLE was conducted using published exposure versus response and efficacy versus time data. Statistical analyses included noncompartmental analysis of a drug's area under the effect curve and direct Imax pharmacodynamic (PD) modeling. Six drugs were included: azathioprine, belimumab, cyclophosphamide, hydroxychloroquine, mycophenolate/mycophenolic acid, and rituximab. For belimumab, the net change in responders at week 52 (the primary end point) was nearly identical between 1 adult trial and the pediatric trial. For mycophenolate, PD modeling suggested no significant differences in exposure and SLE disease activity between adults and children. For azathioprine, cyclophosphamide, hydroxychloroquine, and rituximab the data were not sufficient to quantitatively characterize the exposure-response relationship, but the clinical or pharmacologic response between children and adults was similar overall. Adult SLE data should be leveraged to guide pediatric drug development programs and identify areas with residual uncertainty regarding the effectiveness or safety of a drug in children. The degree to which efficacy extrapolation can reduce clinical trial requirements in pediatric SLE should be individualized for each new drug product, depending in part on the mechanism of action of the drug and the similarity of disease manifestations in children and adults.

Prenatal Somatic Cell Gene Therapies: Charting a Path Toward Clinical Applications (Proceedings of the CERSI-FDA Meeting)

We are living in a golden age of medicine in which the availability of prenatal diagnosis, fetal therapy, and gene therapy/editing make it theoretically possible to repair almost any defect in the genetic code. Furthermore, the ability to diagnose genetic disorders before birth and the presence of established surgical techniques enable these therapies to be delivered safely to the fetus. Prenatal therapies are generally used in the second or early third trimester for severe, life-threatening disorders for which there is a clear rationale for intervening before birth. While there has been promising work for prenatal gene therapy in preclinical models, the path to a clinical prenatal gene therapy approach is complex. We recently held a conference with the University of California, San Francisco-Stanford Center of Excellence in Regulatory Science and Innovation, researchers, patient advocates, regulatory (members of the Food and Drug Administration), and other stakeholders to review the scientific background and rationale for prenatal somatic cell gene therapy for severe monogenic diseases and initiate a dialogue toward a safe regulatory path for phase 1 clinical trials. This review represents a summary of the considerations and discussions from these conversations.

Industry Perspective on Using MIDD for Pediatric Studies Requiring Integration of Ontogeny

Joining the Food and Drug Administration/University of Maryland Center of Excellence in Regulatory Science and Innovation Workshop to discuss and identify solutions to optimize pediatric drug development and, in particular, to address the question as to whether we are ready to incorporate pediatric ontogeny into modeling was the opportunity to share learnings, confront ideas, and present examples of studies performed in industry and academia. This was not only the opportunity to reflect on the experience and the knowledge so far within the current regulatory framework but also to look at the future and explore new and future approaches as well as best practices with the use of modeling and simulation and extrapolation as part of pediatric development.

Primary Endpoints in Pediatric Efficacy Trials Submitted to the US FDA

The selection of appropriate endpoints in pediatric drug development trials is a critical aspect of trial design. Given the high pediatric trial failure rate, selecting optimal trial design elements, such as the primary efficacy endpoint, is essential to ensuring increased potential for trial success. The objectives of this study were to identify the primary efficacy endpoints measured in pediatric drug development trials submitted to the US Food and Drug Administration and to relate endpoint attributes to trial and label outcome. The analysis included pediatric pivotal efficacy studies submitted from September 2007 to July 2016 for which there was a corresponding adult trial for the same indication. Two hundred and thirty-four efficacy trials on 138 unique products studied in pediatric patients were assessed. The adult and pediatric endpoints were the same in 141 of the 234 trials (60.3%), and these trials succeeded in meeting their primary endpoint more often (122 of 141 [86.5%]) than when the adult and pediatric endpoints differed (57 of 93 [61.3%]; odds ratio, 4.03; 95%CI, 2.10-7.80). Trials that included both pediatric and adult patients succeeded more frequently than those trials that did not combine pediatric and adult patients (85 of 95 versus 94 of 139, respectively; odds ratio, 4.05; 95%CI, 1.94-9.31). No differences were observed in pediatric trial success between those using subjective and objective endpoints. Using the same endpoint in the pediatric trial as was measured in the corresponding adult trial and enrolling pediatric and adult patients in the same trial were attributes associated with trial success.