Growing Drug Development for Pediatric Rare Diseases, But More Efforts Focus on Expanding Use of Existing Drugs

Rare Daily Staff

The number of treatments for rare diseases affecting children has increased, but a new study finds federal incentives intended to encourage drug development for rare diseases are more often being used to expand the use of existing drugs rather than for creating new ones.

The Orphan Drug Act provides incentives to drug developers, such as tax credits, grants for testing, and a seven-year period of exclusivity to forestall competition. Researchers at the University of Michigan report in a study published in the journal Pediatrics that of the 402 orphan drug indications approved through the U.S. Food and Drug Administration between 2010 and 2018, a third were specifically for children or for diseases that predominantly affected children.

Most of these pediatric orphan drug approvals were new uses of existing drugs, some of which are decades old and had already been approved to treat common diseases. Only 20 received breakthrough designation, which is granted to drugs that hold promise for improving upon existing treatments.

“Although the Orphan Drug Act has been effective in incentivizing drug development, our findings suggest that not all pediatric orphan indications hold the same value,” said lead author Lauren Kimmel, a research assistant at the University of Michigan Medical School and CHEAR. “Policymakers should ensure that resources are being used efficiently and effectively to stimulate development of new therapies for rare diseases that don’t have any treatment options.”

The researchers found that the 136 pediatric orphan drug approvals targeted 87 unique diseases, most commonly cystic fibrosis, acute lymphoblastic leukemia, and immune disorder hereditary angioedema.

“Our study reveals reason for optimism and reason for concern,” said senior author Kao-Ping Chua, a pediatrician and researcher at Michigan Medicine C.S. Mott Children’s Hospital. “Many pediatric orphan indications may have represented breakthroughs for children with rare diseases. At the same time, most indications were not for new drugs, and some represented relatively minor expansions of use. Orphan drugs are costly to society, and it’s important to make sure that these costs are justified by the amount of benefit to patients.”

Photo: Lauren Kimmel, lead author of the study and a research assistant at the University of Michigan Medical School and CHEAR