By Elizabeth Mechcatie  |  Thu, 29 Jul 2010 23:37 GMT
Elsevier Global Medical NewsBreaking NewsADELPHI, Md. (EGMN) – A Food and Drug Administration advisory panel on July 29 voted 7 to 6 that a specific hemodynamic measure of response to drugs approved for pulmonary arterial hypertension in adults could be used to demonstrate the drugs’ efficacy in children with the disease, and to determine dosing in children. Members of the FDA’s Cardiovascular and Renal Drugs Advisory Committee who voted positively said that while that measurement – the pulmonary vascular resistance index (PVRI) – had limitations, its use as an end point in studies of drugs in children would help get effective drugs approved for the pediatric pulmonary arterial hypertension (PAH) population and would be more useful than the 6-minute walking test in this population, which is used as a clinical end point in adult studies. The pulmonologists and the pediatric cardiologist on the panel explained that while there were some differences, they said they believed PAH in children was similar enough to the disease in adults – including hemodynamic manifestations – that PVRI results could be used to extend the adult indication to children. The FDA is considering making the PVRI a basis for expanding the indication of drugs approved for PAH in adults to children with PAH. Currently, none of the drugs approved for treating PAH in adults is approved in children with the disease. In adults, sildenafil and other drugs for PAH have been approved based on studies that demonstrated improvements in exercise capacity associated with treatment. But exercise testing in children, particularly among those under age 7 years, is difficult to perform, and another way to objectively measure responses to treatment in this population is needed. At the meeting, Pfizer Inc., the manufacturer of the phosphodiesterase-5 inhibitor sildenafil, which was approved for adult PAH in 2005, presented data from adult studies and a pediatric study that showed improvements in exercise capacity were associated with improvements in PVRI. (Pfizer markets sidenafil as Revatio for PAH and as Viagra for erectile dysfunction.) In 2001, the FDA issued a written request to Pfizer to conduct a pediatric study of sildenafil for pediatric PAH. In response, the company conducted a study of 234 patients, which was started in 2003 and used exercise testing as the main end point. However, because of the difficulty performing exercise testing in children, the company has requested that hemodynamic data in children also be included. The panel was asked to vote on whether they thought the available hemodynamic data should be included, but declined because of insufficient data to make the decision. Pfizer was planning to file for approval of sildenafil for PAH in children, if the panel had voted that the hemodynamic data could be included. A statement issued by the company after the meeting said that the company was encouraged by the panel’s discussion about “establishing a path forward for conducting clinical trials for pediatric patients” with PAH, and that it planned to continue to work with the agency to evaluate the findings of the pediatric PAH study, with the goal of gaining approval for this population. Members of FDA advisory panels have been cleared of conflicts related to the topic under discussion. Subject Codes: top_stories; pediatrics; pulmonology; cardiology; http://www.imng.com July 29, 2010   07:37 PM EDT