Merck's Keytruda Nets Another Win in Melanoma
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The approval of Keytruda (pembrolizumab), an anti-PD-1 therapy, is indicated for adults and children ages 12 years and older with IIB or IIC melanoma, and also now includes stage III melanoma following complete resection for pediatric patients 12 years and up.
Keytruda is already approved for multiple other indications, including non-small cell lung cancer, alongside pemetrexed and platinum chemotherapy, head and neck squamous cell cancer in combination with platinum and fluorouracil (FU), classical Hodgkin lymphoma, urothelial carcinoma and primary mediastinal large B-cell lymphoma, among other types of cancers. It is administered intravenously and works by enhancing the immune system to help detect and combat tumor cells.
The FDA's decision is based on the first interim findings from the Phase III KEYNOTE-716 trial, where Keytruda demonstrated a statistically significant change in recurrence-free survival (RFS) and a 35% reduction in the risk of disease recurrence or death. When patients were followed up after a median of 14.4 months, 11% of those who received the drug either had a recurrence or died, compared to the higher 17% for the placebo group. The efficacy for pediatric users was taken from data observed in adults.
The trial enrolled 976 participants who were randomized to receive 200 mg or the pediatric dose of 2mg/kg via IV every three weeks for up to one year until unacceptable toxicity or disease recurrence. Patients were not previously treated for melanoma beyond complete surgical resection. The primary outcome was RFS. The participants were also asked to undergo imaging every six months in the first to fourth years and then once in year five.
"Keytruda was the first anti-PD-1 therapy to be approved in metastatic melanoma in the U.S. seven years ago. Since then, we have built on this foundation in melanoma and have expanded the use of Keytruda into earlier stages of this disease," Dr. Scot Ebbinghaus, vice president for clinical research at Merck Research Laboratories, said in a statement. "With today’s approval, we can now offer healthcare providers and patients 12 years and older the opportunity to help prevent melanoma recurrence with Keytruda across resected stage IIB, stage IIC and stage III melanoma."
Though the drug is not totally clear of immune-mediated adverse reactions, the study urges close monitoring in the early stages of treatment to identify and manage any side effects. If these occur, Keytruda must be either withheld or permanently discontinued and then corticosteroids given as needed. It is also not recommended for pregnant women.
Melanoma is the most severe form of skin cancer, characterized by the uncontrolled growth of pigments. In 2020, almost 325,000 new cases were recorded worldwide. In the U.S., over 106,000 new cases are expected in 2021, resulting in over 7,000 deaths. Recurrence rates are at 32% to 46% for stage IIB and IIC disease and 39% to 74% for stage III. Detecting cancer earlier may increase a patient's survival.