Findings from a single-arm phase II study of combination regimen consisting of nivolumab and ipilimumab in patients with metastatic uveal melanoma demonstrate activity with deep and sustained confirmed responses. Dr Meredith S. Pelster of The University of Texas MD Anderson Cancer Center, Division of Cancer Medicine in Houston, TX, US and colleagues published the study results on 30 October 2020 in the Journal of Clinical Oncology. In their article they point out to an overall response rate (ORR) of 18%, a median progression-free survival (PFS) of 5.5 months and a median overall survival (OS) of 19.1 months with combination therapy in the setting of melanoma patients for which currently there is no standard therapy.
The investigators wrote in the study background that uveal melanoma is the most common primary intraocular malignant tumour in adults. Uveal melanoma is the second most common type of primary melanoma; however, it represents only 5% to 6% of all melanoma diagnoses. The incidence of uveal melanoma globally is approximately 4,800 cases per year. Despite effective local therapies, 40% to 50% of patients will develop metastases with liver metastases present in up to 95% of cases. Median survival of patients with metastatic disease is 6 to 12 months only.
Benefit of immune checkpoint inhibitors in rare subtypes of melanoma, including uveal melanoma, requires additional investigation. Studies of single-agent immune checkpoint inhibitors demonstrated low response rate. The study team hypothesised that dual immune checkpoint inhibition would improve anti-tumour responses in metastatic uveal melanoma.
They conducted a single-institution, open-label, single-arm phase II study of nivolumab and ipilimumab in patients with metastatic uveal melanoma. Any number of prior treatments was permitted. Patients received nivolumab 1 mg/kg and ipilimumab 3 mg/kg for four cycles, followed by nivolumab maintenance therapy for up to 2 years.
The study primary outcome was ORR determined by RECIST v1.1. The PFS, OS and adverse events were also assessed. In total, 35 were enrolled in the study, but 33 patients were evaluable for efficacy.
The ORR was 18%, including 1 confirmed complete response and 5 confirmed partial responses.
Median PFS was 5.5 months (95% confidence interval [CI] 3.4 to 9.5 months) and median OS was 19.1 months (95% CI 9.6 months to non-reached).
A grade 3/4 treatment-related adverse event was experienced by 40% of patients.
The authors concluded that nivolumab in combination with ipilimumab demonstrates anti-tumour activity in patients with metastatic uveal melanoma. They wrote that the results from their study and the Spanish GEM-1402 study indicate that this combination is active and should be considered for this patient population. Additional studies are needed to characterise the molecular and genomic signatures of responders and non-responders.
The study was supported by Bristol Myers Squibb and The University of Texas MD Anderson High Impact Clinical Research Support Program.
Pelster MS, Gruschkus SK, Bassett R, et al. Nivolumab and Ipilimumab in Metastatic Uveal Melanoma: Results From a Single-Arm Phase II Study. JCO; Published online 30 October 2020. DOI: 10.1200/JCO.20.00605.