Posted 20 December 2016
By Michael Mezher
A team of officials at the US Food and Drug Administration (FDA) are calling for a "culture shift" by drugmakers, regulators and clinical investigators to encourage enrolling more adolescent patients in relevant "adult-type" cancer clinical trials.
The officials made the call in a recent article in Clinical Cancer Research, where they argue that excluding older adolescents, ages 12 to 17, from adult oncology trials leads to delayed access to new treatments for those patients.
"In order to facilitate earlier access to investigational and approved drugs for adolescent patients with cancer, and because drug exposure is most often similar in adolescents and adults, we recommend the inclusion of adolescents (ages 12-17) on disease and target-appropriate adult oncology trials," the officials write.
"Some of the most common cancers in adolescent patients are similar to those seen in adults, including some soft tissue and bone sarcomas, [central nervous system] CNS tumors, leukemias and lymphomas, and melanoma," the authors write.
While the authors say that most pediatric cancer patients are enrolled in clinical trials, older adolescents are enrolled at much lower rates. For instance, only 10-15% of adolescent patients with cancer between ages 15 and 19 participate in oncology trials.
The authors say this discrepancy is an issue, as clinical trial participation is considered one of the major factors in the "more than 50% decrease in overall childhood cancer mortality since 1975."
In part, the authors attribute this discrepancy to a "lack of access to relevant trials" for adolescents, as they are often considered ineligible for adult oncology trials and pediatric trials often occur years afterwards.
These delays, the authors say, have serious consequences: "accrual to pediatric trials evaluating drugs already approved in adults may be seriously threatened by 'off-label' use in children; there are no prospectively collected data in product labeling to guide the prescribing physician on safe and effective use of the drug in adolescents at the time of adult approval; and, most importantly, the current approach contributes to delayed access to investigational and effective approved drugs for adolescent patients with more 'adult-type' cancers."
Dr. Vinay Prasad, an oncologist at the Oregon Health & Science University, told Focus he supports including more adolescents in adult oncology trials, arguing adolescents and other minority groups are at a "disadvantage" by not being equally represented.
"The authors' proposal is to be commended. These groups can and should be included in these trials, as long as we take special effort to look for differential safety or efficacy signals," Prasad said.
Challenges and Solutions
However, the authors say there are several potential, but surmountable, barriers to including adolescents in adult oncology trials.
Some of the logistical issues may be addressed by revising age eligibility criteria for the trials and by relying on a single institutional review board.
These changes, the authors say, would "allow for the enrollment of adolescents on relevant clinical trials when they are managed outside of a pediatric setting" and improve multi-center trial oversight.
The authors also say that FDA already allows for some flexibilities regarding preclinical studies ahead of trials involving pediatric patients: "Consistent with the [International Council for Harmonisation] ICH S9 guidance, FDA does not always require juvenile animal studies prior to the initiation of pediatric assessment of a drug. Juvenile animal studies may be warranted when the known mechanism of action of a drug is likely to cause developmental toxicities or when available clinical or nonclinical data is not sufficient to provide information on relevant toxicities, but are not routinely needed prior to the evaluation of oncology drugs in pediatrics."
Enrolling adolescents in disease/target-appropriate adult oncology clinical trials of investigational agents