Combining nivolumab with radiation therapy (RT) may improve objective responses and outcomes in patients with unresectable hepatocellular carcinoma (HCC), according to new data presented at the 2019 American Society for Therapeutic Radiation Oncology (ASTRO) Annual Meeting in Chicago, Illinois. Researchers found the objective response rate as determined by mRECIST criteria was approximately 35%, substantially increased from historical controls, suggesting that this approach may help boost the number patients who might benefit from immune checkpoint inhibition.
“This finding is consistent with findings in other disease sites where radiation therapy has been shown to improve response to immunotherapy,” said study investigator William Smith, MD, who is a resident physician of radiation oncology, Mount Sinai Health System, New York, New York.
The researchers retrospectively identified 84 patients who received both nivolumab and RT between January 2012, and September 2018, for HCC; 35 patients met inclusion criteria. They separately analyzed patients who received upfront RT prior to/overlapping with nivolumab initiation (25 patients) and patients receiving salvage RT (9 patients) for longer than 4 weeks following nivolumab initiation.
With a median follow-up 17.8 months, among responders, the median duration of response was 9.8 months. As previously noted, upfront RT yielded an approximate 35% ORR compared with 15% to 20% in historical controls. Dr Smith, who presented the findings at the meeting, said salvage RT failed to produce an abscopal response. However, among patients receiving upfront RT, they found that progression-free survival was superior, and overall survival trended toward improvement among responders. “We need to invest in trials combining radiation therapy and immunotherapy as part of a multimodal approach to improve outcomes for patients with unresectable hepatocellular carcinoma. We believe this approach represents a promising treatment paradigm that may enhance the benefit we see from immunotherapy without significant additional toxicity,” Dr Smith told Cancer Therapy Advisor.
Smith W. The effect of radiation therapy on the objective response and outcomes with nivolumab for hepatocellular carcinoma. Presented at: 2019 American Society for Therapeutic Radiation Oncology (ASTRO) Annual Meeting; September 15-18, 2019; Chicago, Illinois. Abstract 1199.