Research Chelation Therapy

by Julia Hawes
Feb 15, 2009

Children, one of the more vulnerable patient groups, are often treated with medicine that has only been tested in adults, researchers said Saturday at the American Association for the Advancement of Science conference.

“About three-quarters of the drugs, I actively prescribe to my pediatric patients daily have never been adequately tested in children,” said Dr. Michael Shannon, who works in pediatrics and clinical pharmacology at Children’s Hospital Boston. He estimated that the number increased to almost 90 percent in pediatric intensive care units.

Shannon and other speakers at the “Medicines for Children” symposium argued that the disparity between adult and pediatric physiology is great enough that there are both ethical and medical implications of administering medicine that has not been tested expressly for pediatric use.

“The assumption that children are just small adults consistently results in drug overmedication, undermedication and unanticipated adverse events,” Shannon said. “There’s a great need to expand drug discovery and development in children.”

Shannon and other researchers have found their subject and research areas are affected by the limited number of adequately tested pediatric medicine.

He explained the benefits of chelating drugs on childhood lead poisoning. Such drugs eliminate lead from the body, but not always when the lead levels are lower than with severe poisoning.

D-Penicillamine can serve as both a copper and lead chelator, even in children with lower lead levels. However, children given large quantities of the drug have suffered adverse side effects, such as hepatitis and aplastic anemia, resulting in a high failure rate for the chelator. Shannon described a federally funded penicillamine clinical trial for children aimed at learning how to better study a drug—previously only tested on adults—may be improved for pediatric use.

Gilles Vassal, a cancer specialist with the Institut de Cancérologie Gustave Roussy in Villejuif, France, outlined a plan to expand oral pharmaceuticals and therapies for children suffering from cancer. Unfortunately, he said, many of the basic cancer-fighting compounds are not available for children from the pharmaceutical companies.

“The market is too small, and the return investment is not high enough,” Vassal said.

The panel agreed that the focus on changes in childhood metabolism should be expanded in order to develop new pharmaceuticals, whether it’s in using lorazepam for epilepsy or cyclophosphamide for leukemia and lymphoma. The latter is not currently available as an easily administered oral drug for young children—especially those who cannot swallow medicine—and Vassal hopes research on the drug can be expanded to better serve pediatric oncology patients.

Shannon described the basic ways a new drug are discovered and subsequently developed—modification of an existing drug; test uube or animal testing; basic clinical observation, and systematic clinical research.

Despite two American laws relating to pediatric drug development, clinical trial methods remain controversial.

Shannon, Vassal and Dr. Fergal Donnelly, an officer in health biotechnology with the European Commission, feel that the ethical concerns surrounding pediatric clinical trials must be compared to what they feel is the more extreme ethical challenge—children being administered medicine that has not been tested adequately.

The international panel expressed hopes that there would be closer integration of European and U.S. research in pediatric medicine.

Donnelly dismissed a question about whom exactly the European Commission and domestic facilities are trying to serve with the push for more testing because of the interplay with the pharmaceutical industry.

“We are not responding to the needs of the industry, but to the needs of our patients,” Donnelly said.