Dr. Richard Pazdur, director of the Office of Hematology and Oncology Products in the FDA's Center for Drug Evaluation and Research, said the drug therapy is used on melanoma -- the most aggressive type of skin cancer -- that cannot be removed by surgery -- unresectable -- or metastatic -- late-stage melanoma.
Last May, the FDA approved both drugs as single agents to treat patients with unresectable or metastatic melanoma.
Mekinist and Tafinlar are used to block signaling in different sites of the same molecular pathway that promotes cancer cell growth. They are specifically indicated as a combination therapy for patients with melanoma whose tumors express gene mutations called BRAF V600E and V600K. The BRAF protein is involved in the regulation of normal cell growth, but it is mutated in approximately half of melanomas arising from the skin, Pazdur said.
"Mekinist and Tafinlar are the first drugs approved for combination treatment of melanoma," Pazdur said in a statement.
The safety and effectiveness of Mekinist in combination with Tafinlar were demonstrated in a clinical trial of 162 participants with unresectable or metastatic melanoma with the BRAF V600E or V600K mutation, most of whom had not received prior therapy. Participants received either Mekinist in combination with Tafinlar or Tafinlar as a single agent until their melanoma progressed or side effects became intolerable, Pazdur said.
Seventy-six percent of participants treated with Mekinist in combination with Tafinlar saw their cancer shrink or disappear for an average of 10.5 months. In contrast, 54 percent of participants treated with Tafinlar as a single agent experienced these responses for an average 5.6 months. Clinical trials are ongoing to determine whether Mekinist in combination with Tafinlar improves survival.
The most common side effects reported for Mekinist in combination with Tafinlar included: fever, chills, tiredness, rash, nausea, vomiting, diarrhea, abdominal pain, swelling in the hands and feet, cough, headache, joint pain, night sweats, decreased appetite, constipation and muscle pain.