A study under way in the Netherlands to document the effectiveness of the use of drugs off-label for cancer has produced its first results. The Drug Rediscovery Protocol, or DRUP, is an ongoing multicenter trial for patients with advanced or metastatic cancer. Results from the first 215 patients indicated that overall, approximately 30% of patients benefited from the off-label prescriptions, where benefit is defined as complete or partial remission, or stable disease after 16 weeks.1
The goal of the study was to provide opportunities for patients who have run out of options, said Emile Voest, MD, PhD, director of the Netherlands Cancer Institute (NKI), Amsterdam, and the study’s senior author. Genomic sequencing of metastatic cancers revealed that 13% of patients carried a genetic target for which a drug was already approved, but not for use for their particular tumor type. “These are ready-to-go opportunities for patients,” Dr Voest said, “but if we truly want to make sure we collect all the necessary information, we need to run it as a trial.”
In some countries, including the United States, it’s legal — albeit complicated — to prescribe drugs for indications that fall outside of the FDA-approved uses that are listed on the drug’s label. Many cancer patients do receive off-label therapies — but without a formal system for collecting and communicating the results of their treatment, these data remain largely anecdotal.
The DRUP trial, along with the Targeted Agent and Profiling Utilization Registry (TAPUR) study,2 in the United States, and the Canadian Profiling and Targeted Agent Utilization Trial (CAPTUR), in Canada, aim to document the successes and failures of off-label uses, both to guide doctors in prescribing off label and to encourage drug companies to seek formal approval for expanded usage.
To qualify for the trial, a patient must have exhausted all standard-of-care therapies, and the cancer must carry an actionable genetic variant for which a targeted therapy has been approved. Patients are then slotted into cohorts defined by the tumor tissue of origin, the therapy they’ve received, and the mutation found in the tumor.
The study design allows for unlimited parallel cohorts to be tested. In the first stage, 8 patients are enrolled in a cohort, and if no patient responds to the drug, then that cohort is closed. However, if at least 1 patient experiences a remission, the cohort will be expanded to include 24 patients.