The FDA last week approved drugs for pancreatic cancer and a rare form of leukemia that affects both adults and children.
The agency approved erlotinib (Tarceva), in combination with gemcitabine, as a first-line treatment for patients with advanced, inoperable, or metastatic pancreatic cancer. The approval was based on a single phase III randomized clinical trial in which the combination of erlotinib, an EGFR-inhibitor approved approximately a year ago for the treatment of non-small-cell lung cancer, and gemcitabine, the standard treatment for these patients, resulted in a small but statistically significant improvement in survival compared with gemcitabine alone. The median improvement in survival was only 12.8 days, but the 1-year survival rates favored the addition of erlotinib, 24 percent versus 17 percent.
During a meeting in September, the FDA Oncology Drugs Advisory Committee voted in favor of approving erlotinib for this new indication. Committee members struggled with whether such a small survival improvement - which could be accompanied by an increase in diarrhea and skin rash - was enough to justify an approval recommendation. In the end, most committee members agreed, as one put it, that the approval would be an important "first step" toward new options for what is an almost uniformly fatal form of cancer.
The agency also approved nelarabine (Arranon) to treat adults and children with T-cell acute lymphoblastic leukemia (T-ALL) and T-cell lymphoblastic lymphoma (T-LBL), and whose disease is refractory to or has relapsed following at least two chemotherapy regimens. Nelarabine, which was approved under an accelerated approval mechanism and also granted orphan drug status, is the first drug cleared for this rare indication; an estimated 500 patients per year have relapsed or refractory disease.
FDA based the accelerated approval - which requires the drug's manufacturer, GlaxoSmithKline, to conduct additional studies to verify clinical benefit - on two NCI-sponsored phase II clinical trials. The nelarabine phase II trial in children was conducted by the Children's Oncology Group (COG), while the trial in adults was led by the Cancer and Leukemia Group B, in conjunction with the Southwest Oncology Group. In both trials, complete responses were observed in approximately 20 percent of patients. Median overall survival was 21 weeks in adults and 13 weeks in children. The post-approval study will be an NCI-sponsored phase III trial conducted by COG and will include event-free survival at 4 years as an endpoint.
"It is very important to now have this drug available," said Dr. Kimberly P. Dunsmore, associate professor of pediatrics at the University of Virginia Health System. "It's proven to be quite effective in the phase I and II settings." Nelarabine's effectiveness in the trials to date is welcome, she adds, because patients have typically been refractory to other drugs tested for this indication.
Dr. Dunsmore is the principal investigator for a COG-conducted pilot study testing nelarabine upfront in patients with T-ALL or T-LBL who are at increased risk for relapse. The trial recently closed to accrual.