BARCELONA – Checkpoint inhibition with nivolumab led to a clinically meaningful, but not statistically significant, improvement in overall survival, compared with sorafenib for the first-line treatment of advanced hepatocellular carcinoma (HCC) in the phase 3 CheckMate 459 study.
Median overall survival (OS), the primary study endpoint, was 16.4 months in 371 patients randomized to receive the programmed death-1 (PD-1) inhibitor nivolumab, and 14.7 months in 372 patients who received the tyrosine kinase inhibitor sorafenib – the current standard for advanced HCC therapy (hazard ratio, 0.85; P = .0752), Thomas Yau, MD, reported at the European Society for Medical Oncology Congress.
The median OS seen with nivolumab is the longest ever reported in a first-line phase 3 HCC trial, but the difference between the arms did not meet the predefined threshold for statistical significance (HR, 0.84 and P = .419). However, clinical benefit was observed across predefined subgroups of patients, including those with hepatitis infection and those with vascular invasion and/or extrahepatic spread, said Dr. Yau of the University of Hong Kong.
The overall response rates (ORR) were 15% and 7% in the nivolumab and sorafenib arms, with 14 and 5 patients in each group experiencing a complete response (CR), respectively, he said.
At 12 and 24 months, the OS rates in the groups were 59.7% vs. 55.1%, and 36.5% vs. 33.1%, respectively. Median progression-free survival (PFS) was similar in the groups, at 3.7 and 3.8 months, respectively, and analysis by baseline tumor programmed death-ligand 1 (PD-L1) expression showed that ORR was 28% vs. 9% with PD-L1 expression of 1% or greater in the groups, respectively, and 12% vs. 7% among those with PD-L1 expression less than 1%.
Additionally, nivolumab had a more tolerable safety profile; grade 3/4 treatment-related adverse events were reported in 22% and 49% of patients in the groups, respectively, and led to discontinuation in 4% and 8%, respectively. No new safety signals were observed, Dr. Yau said.
Participants in the multicenter study were systemic therapy–naive adults with advanced disease. They were randomized 1:1 to receive intravenous nivolumab at a dose of 240 mg every 2 weeks or oral sorafenib at a dose of 400 mg twice daily, and were followed for at least 22.8 months.
“These results are important in the treatment of hepatocellular carcinoma, as there have been no significant advances over sorafenib in the first-line setting in more than a decade,” Dr. Yau said in an ESMO press release. “HCC is often diagnosed in the advanced stage, where effective treatment options are limited. The encouraging efficacy and favorable safety profile seen with nivolumab demonstrates the potential benefit of immunotherapy as a first-line treatment for patients with this aggressive cancer.”
He further noted that the OS benefit seen in this study is “particularly impactful considering the high frequency of subsequent use of systemic therapy, including immunotherapy, in the sorafenib arm,” and that the OS impact is bolstered by patient-reported outcomes suggesting improved quality of life in the nivolumab arm.
Nevertheless, the fact that CheckMate 459 did not meet its primary OS endpoint means the findings are unlikely to change the current standard of care, according to Angela Lamarca, MD, PhD, consultant medical oncologist and honorary senior lecturer at the Christie NHS Foundation Trust, University of Manchester (England).
She added, however, that the findings do underscore a potential role for immunotherapy in the first-line treatment of advanced HCC and noted that the clinically meaningful improvement in response rates with nivolumab, along with the checkpoint inhibitor’s favorable safety profile in this study, raise the possibility of its selection in this setting.
“In a hypothetical scenario in which both options ... were available and reimbursed, and if quality of life was shown to be better with nivolumab ... clinicians and patients may favor the option with a more tolerable safety profile,” she said in the press release.
She added, however, that at this point conclusions should be made cautiously and the high cost of immunotherapy should be considered.
Dr. Lamarca also highlighted the finding that patients with high PD-L1 expression had an increased response rate only in the nivolumab arm. This suggests a potential role for PD-L1 expression as a predictive biomarker in advanced HCC, but more research is needed to better understand how to select patients for immunotherapy, she said, adding that the lack of a reliable biomarker may have contributed to the study’s failure to show improved OS with nivolumab.
“In addition, the study design with a ‘high’ predefined threshold of statistical significance is generating confusion in the community, with potentially beneficial therapies generating statistically negative studies,” she noted.
CheckMate 459 was funded by Bristol-Myers Squibb. Dr. Yau is an advisor and/or consultant to Bristol-Myers Squibb, and reported honoraria from the company to his institution. Dr. Lamarca reported honoraria, consultation fees, travel funding, and/or education funding from Eisai, Nutricia, Ipsen, Pfizer, Bayer, AAA, Sirtex, Delcath, Novartis, and Mylan, as well as participation in company-sponsored speaker bureaus for Pfizer, Ipsen, Merck, and Incyte.
SOURCE: Yau T et al. ESMO 2019, Abstract LBA38-PR