WASHINGTON — Four experimental cancer treatments that may one day help gravely ill children are facing review by U.S. pediatric advisers who have been working for years to find ways to develop more drugs for this underserved population.
The medicines from GlaxoSmithKline, Amgen, Threshold Pharmaceuticals and Boehringer Ingelheim have the potential to treat children with a variety of tumors and fast-spreading leukemia.
The pediatric advisers to the Food and Drug Administration met Wednesday to discuss how best to test the medicines in sophisticated clinical trials in kids that may eventually lead to marketing approval.
Companies typically gain clearance for cancer medicines in adults first and then take the time to learn more about the drugs’ potential in younger patients, a smaller and less profitable market.
That approach, though, has led to only 15 such medicines being allowed for use in children since 1998.
Childhood cancers are “therapeutic orphans,” said Richard O’Reilly, chairman of the Department of Pediatrics at the Memorial Sloan-Kettering Cancer Center in New York. “We have long wanted to have access to promising drugs earlier in their development for kids.”
About 10,000 children develop cancer over the course of a year, O’Reilly said, or less than 1 percent of the 1.6 million people in the United States who the American Cancer Society estimates will develop the disease this year.
The new focus on getting adult cancer drugs to youngsters will be aided by legislation taking effect in January that requires drugmakers to discuss pediatric studies earlier than normal for appropriate populations of younger patients. Now, pharmaceutical companies are required by law to study their products in children if the disease exists in the pediatric population.
Children don’t get breast or lung cancer that affect large groups of people. Instead, they suffer from their own deadly malignancies in relatively small numbers, O’Reilly said. An incentive that gives companies six additional months to market their treatment free from generic competition may help coax them into studying their drugs in cancers for younger patients.
The population of pediatric cancer patients is so small that researchers have one shot at studying a particular cancer because trials for a single drug will use up all the children with a targeted disorder, said Susan Weiner, president of the Washington-based Children’s Cause for Cancer Advocacy.
“We have to pick the best bets,” she said.
Acute lymphoblastic leukemia is the most common cancer in children, representing about 23 percent of pediatric cancer diagnoses, according to the National Cancer Institute. About 2,900 children and adolescents younger than 20 in the U.S. are diagnosed with the disease each year, which causes unformed blood cells and peaks among 2- to 3-year-olds.
The doctors and academics convening today are members of a subcommittee of the FDA’s oncology advisory panel. They will advise the agency on helping drug companies advance their understanding of how their medicines might work in children.
Prior meetings haven’t borne fruit as regulators learned how to refine their approach, though New York-based Pfizer’s Xalkori, discussed at the 2010 meeting, is being studied by the Children’s Oncology Group in young patients with solid tumors resistant to treatment, according to ClinicalTrials.gov. Children’s Oncology Group, which said it’s the world’s largest organization devoted exclusively to childhood and adolescent cancer research, has almost 100 clinical trials open at any time and is supported by the Bethesda, Md.-based National Cancer Institute, which is part of the National Institutes of Health.
Each of the four experimental drugs under discussion — trametinib from London-based Glaxo, blinatumomab from Thousand Oaks, Calif.-based Amgen, South San Francisco, Calif.-based Threshold’s TH-302, and volasertib from closely held Boehringer of Ingelheim, Germany — has garnered interest from pediatric oncology doctors, O’Reilly said. Weiner didn’t want to comment on specific drugs.
O’Reilly is part of a trial that just began Amgen’s blinatumomab for acute lymphoblastic leukemia that he expects will study patients in early phase trials over two years.
“Pediatric legislation, including a combination of incentives and requirements, has significantly increased pediatric drug research and development and led to a substantial increase in products with new pediatric information in labeling,” according to an FDA staff report.
Drugmakers are testing 981 medicines and vaccines to fight cancer, according to a May report from the Pharmaceutical Research and Manufacturers of America.