Abstract 738P
Background
Despite immunotherapy has revolutionized the treatment of mccRCC, predicting which patient will benefit from the treatment still remain an issue and more dynamic biomarkers are required for patient selection.
Methods
We performed a prospective study including a cohort of 36 patients with ccRCC: 21 with metastatic disease, 15 with localized disease. In the group of mccRCC patients candidate to nivolumab as second line treatment, peripheral blood samples were collected at baseline, before starting nivolumab (T0), and after a 4-weeks period (T1). The plasma sPD-1, sPD-L1 and pan-sBTN3A, sBTN3A1 and sBTN2A1 levels were measured by specific ELISA assays not yet commercially available.
Results
The median progression free survival (PFS) measured before starting nivolumab treatment (T0) of patients with sPD1<8.05 ng/ml was 5.8 months whereas in the patients with sPD1 >8.05 the median PFS was 17.5 months (p=0.0274). The Wilcoxon test for paired samples showed a statistically significant difference between T0 and T1 for both sPD1 and sBTN2A1 (sPD1: T0 vs T1 p=0.0078; sBTN2A1 T0 vs T1 p=0.0007). For sPD-L1 probably the small number of samples did not allow us to reach statistical significance (p=0.097). In the patients with PFS>18 months, after a 4-weeks period (T1) with nivolumab treatment, levels of sPD1 and sPD-L1 were lower than baseline, with a mean of 1.23 ng/ml (1.06-1.93) for sPD-1 and 0.73 ng/ml (0.56-1.39) for sPD-L1; levels of sBTN2A1 were higher at the 4-weeks period (T1; 9.99 ng/ml; 7.94-19.13) than baseline (T0; mean 7.71 ng/ml; 4.91-10.0). An exploratory analysis in metastatic versus localized ccRCC patients, showed that the concentrations of sPD-1 and sPD-L1 were elevated in the plasma of metastatic in comparison with localized RCC patients (sPD-1 p=0.003; sPD-L1 p=0.164).
Conclusions
Soluble PD-1, PD-L1, pan-BTN3As, BTN3A1 and BTN2A1 could help to identify patient’s subgroups for immune-checkpoint treatment, driving the therapeutic choice and monitoring the patient’s response.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
University of Palermo.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.