The US Food and Drug Administration (FDA) approved the simultaneous administration of Tafinlar (dabrafenib) and Mekinist (trametinib) for the treatment of ATC that cannot be removed by surgery or has metastasized and has the abnormal gene type BRAF V600E (BRAF V600E mutation-positive).
The National Institutes of Health (NIH) estimates there will be 53,990 new cases of thyroid cancer and approximately 2,060 deaths from the disease in the US in 2018.
ATC is aggressive and rare, accounting for only 1% to 2% of all thyroid cancers. The FDA’s approval specifies the two drugs being used together for treatment or simply alone.
Novartis is not combining the drugs at this time.
“This is the first FDA-approved treatment for patients with this aggressive form of thyroid cancer, and the third cancer with this specific gene mutation that this drug combination has been approved to treat,” Richard Pazdur, director of the FDA’s Oncology Center of Excellence and acting director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research, said in the FDA’s announcement of the approval.
“This approval demonstrates that targeting the same molecular pathway in diverse diseases is an effective way to expedite the development of treatments that may help more patients” he added.
The combination of Tafinlar and Mekinist is also approved to treat BRAF V600E mutation-positive, metastatic non-small cell lung cancer.
Clinical trial
The efficacy of both drugs in treating ATC was shown in an open-label clinical trial of patients diagnosed with rare cancers with the BRAF V600E mutation. Data from trials in BRAF V600E mutation-positive, metastatic melanoma or lung cancer and results in other BRAF V600E mutation-positive rare cancers provided confidence in the results seen in patients with ATC.
The clinical trial measured the percent of patients with a complete or partial reduction in tumor size. According the trial’s 23 evaluable patients, 57% experienced a partial response and 4% experienced a complete response. In nine of the 14 patients with responses, there were no significant tumor growths for six months or longer.