On Friday, November 9, the U.S. FDA granted accelerated approval to the checkpoint immunotherapy pembrolizumab (Keytruda®, Merck) for the treatment of certain patients with advanced hepatocellular carcinoma (HCC), the most common form of liver cancer which affects tens of thousands of people in the United States each year.
By targeting the PD-1 checkpoint that can suppress immune responses, pembrolizumab, which is already approved for nine other types of advanced cancer, works by “unleashing” patients’ immune cells and enabling them to eliminate cancer cells they encounter. Now, following last year’s approval of nivolumab, which also targets the PD-1 pathway, pembrolizumab is another important option for people with advanced liver cancer that hasn’t responded to the standard-of-care treatment, sorafenib (NEXAVAR®, Bayer).
“Hepatocellular carcinoma is the most common type of liver cancer in adults, and while we have seen recent therapeutic advancements, there are still limited treatment options for advanced recurrent disease,” according to study leader Andrew X. Zhu, M.D., Ph.D., of Massachusetts General Hospital and Harvard Medical’s School. “Today’s approval of Keytruda is important, as it provides a new treatment option for patients with hepatocellular carcinoma who have been previously treated with sorafenib.”
The FDA’s approval of pembrolizumab was based upon results from the phase II Keynote-224 trial, in which 104 patients with previously treated liver cancer received pembrolizumab. In total, eighteen patients (17%) responded to the immunotherapy, with one patient having their cancer disappear completely. Of the eighteen patients who saw their tumors shrink, 89% of them maintained those responses for at least six months, while just over half (56%) maintained their responses for more than a year.
Unfortunately, because the majority of advanced liver cancer patients still don’t respond to current treatments, the Cancer Research Institute (CRI) remains committed to supporting work aimed at developing new, potentially improved ways that the immune system could be used to address this disease. Several immune-related avenues currently being explored by CRI-funded scientists include: reverse engineering antibodies against the hepatitis C virus, a major cause of liver cancer (Andrew I. Flyak, Ph.D.); the role that immune cells called macrophages play in tumor development and survival (Zihou Deng, Ph.D.); and how obesity can influence liver homeostasis and create an inflammatory environment that promotes the development of liver disease and cancer (Chaoran Li, Ph.D., and Zhenyu Zhong, Ph.D.).
Photo by Rene Böhmer on Unsplash.