A study of Keytruda (pembrolizumab) in patients with a difficult-to-treat type of liver cancer suggests that the treatment may extend the time before their disease progresses.
Data presented at the 2018 American Society of Clinical Oncology Gastrointestinal Cancers Symposium, on Jan. 19, showed that Keytruda stabilized the disease in a significant percentage of patients. However, the treatment should not be viewed as a cure for the majority of patients, as only 1 percent of participants saw their cancer eradicated.
“There continues to be a significant need for new options in the treatment of advanced hepatocellular carcinoma,” Andrew Zhu, MD, PhD, lead investigator and director of liver cancer research at Massachusetts General Hospital Cancer Center, said in a press release. “The durable responses observed with Keytruda monotherapy in this difficult-to-treat cancer are encouraging.”
Developed by Merck (known as MSD outside the U.S. and Canada), the PD-1-targeting checkpoint inhibitor Keytruda is already approved for a range of cancer forms.
The Phase 2 trial, called KEYNOTE-224 (NCT02702414), treated patients with advanced hepatocellular carcinoma (HCC) who had previously been treated with Nexavar (sorafenib). Keytruda was given as the only therapy. Hepatocellular carcinoma is the most common type of liver cancer.
Among 104 patients, the objective response rate was 16.3 percent. Only 1 percent of participants had their cancer eradicated. Meanwhile, the disease control rate was 61.5 percent, meaning that many patients stabilized, but did not improve on the treatment.
The median duration of response was 8.2 months, with the majority of patients having a response for longer than six months, researchers said.
Median progression-free survival was 4.8 months. At six months, 43.1 percent of patients had not progressed, and 77.9 percent were still alive. More than half of treated patients were still alive at the time of the analysis.
Patients in the study experienced similar side effects as those observed in other Keytruda trials. Fatigue, increased liver enzymes, diarrhea, and itch were the most common side effects. One-fourth of patients had severe side effects, and one patient died of treatment-related causes. Seven patients stopped the therapy because of side effects.
“Merck is committed to understanding the clinical benefit of Keytruda monotherapy across a range of gastrointestinal cancers, including advanced liver cancer,” said Roger Dansey, senior vice president and therapeutic area head of oncology late-stage development at Merck Research Laboratories.
“The findings from this study demonstrate the potential of Keytruda in patients with advanced HCC following prior systemic therapy and support the advancement of our clinical development program in this cancer type,” he added.