The US Food and Drug Administration (FDA) has approved Tafinlar in combination with Mekinist (trametinib) for the treatment of anaplastic thyroid cancer (ATC).
The combination treatment has been approved for patients with ATC that cannot be removed by surgery or has spread to other parts of the body, and is BRAF V600E mutation-positive.
A BRAF V600E mutation is a specific mutation in the BRAF gene that makes a protein involved in sending signals in cells and in cell growth. The gene abnormality can occur in several types of cancer, including melanoma and colorectal cancer, and may increase the growth and spread of cancer cells.
Tafinlar in combination with Mekinist is currently approved in the US for patients with unresectable or metastatic melanoma with a BRAF V600E/K, and non-small cell lung cancer with a BRAF V600E mutation. The safety and efficacy profile of the Tafinlar and Mekinist combination has not yet been established outside of the approved indications.
The efficacy of Tafinlar and Mekinist in treating ATC was shown in an open-label clinical trial of patients with rare cancers with the BRAF V600E mutation. The trial measured the percentage of patients with a complete or partial reduction in tumour size. Of the 23 evaluable patients, 57% experienced a partial response and 4% experienced a complete response.
ATC is a rare form of thyroid cancer that often has a poor prognosis due to its aggressive behaviour and resistance to cancer treatments. The National Institutes of Health estimates there will be 53,990 new cases of thyroid cancer and an estimated 2,060 deaths from the disease in the US in 2018.
The FDA granted Priority Review and Breakthrough Therapy designation for this indication. Orphan Drug designation was also granted, designed to encourage the development of drugs for rare diseases.
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 Dr Richard Pazdur said: “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. 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.”