Baseline plasma levels of soluble PD-1, PD-L1, and BTN3A1 predict response to nivolumab treatment in patients with metastatic renal cell carcinoma: a step toward a biomarker for therapeutic decisions

Figures & data

Figure 1. The assessment of PD-L1 expression using immunohistochemistry (IHC) staining in formalin-fixed paraffin-embedded (FFPE) tissue samples shows several limitations inherent to the tissue sampling, IHC detection methods and used antibodies. Circulating ICs could represent more dynamic biomarkers and be useful to predict the effect of the anti-PD-1 monoclonal antibody against RCC

Table 1. Clinical and pathological features of localized RCC patients

Baseline characteristics Tot (n)	15
Median age (range) – years	61 (31–87)
Sex Male Female	11 (73.3%) 4 (26.7%)
Histological classification Clear cell Others	15 (100%) 0 (0%)
Type of surgery Partial Nephrectomy Radical Nephrectomy	7 (46.7%) 8 (53.3%)
AJCC/UICC TNM classification Stage I Stage II Stage III	7 (46.7%) 5 (33.3%) 3 (20%)

Table 2. Clinical and pathological features of metastatic RCC patients

Baseline characteristics Tot (n)	21
Median age (range) – years	61 (36–70)
Sex, n (%) Male Female	19 (90.5%) 2 (9.5%)
Histological classification Clear cell Other	21 (100%) 0 (0%)
Prior nephrectomy Yes No	5 (23.8%) 16 (76.2%)
No. of evaluable disease sites, n (%) ≤2 ≥3	4 (19.1%) 17 (80.9%)
Site of metastasis Lung only Lung + others	6 (28.6%) 15 (71.4)
Site of metastasis, individual Lung Lymph node Liver Bone Pancreas SNC	10 (47.6%) 11 (52.4%) 6 (28.6%) 5 (23.8%) 1 (4.7%) 4 (19%)
IMDC Prognostic Risk Group, n (%) Favorable Intermediate Poor	6 (28.6%) 15 (71.4%) 0 (0%)
Best response to nivolumab treatment
Complete response (CR)	1 (4.7%)
Partial response (PR) Stable disease (SD) Progressive disease (PD)	9 (42.9%) 10 (47.7%) 1 (4.7%)
Median duration of response (range) – months	14 (3–28)

Table 3. Median and range of pretreatment (T0) levels of plasmatic ICs in all mccRCC patients and in long-responders (>18 months) group

ICs	All Nivolumab pts N = 21	Long-responders pts (PFS>18mo) N = 9	p value *
sPD-1 Median (ng/ml) Range	2.00 0.52–25.00	13.25 1.22–25.00	p = .01
sPD-L1 Median (ng/ml) Range	0.64 0.26–1.31	1.09 0.47–2.41	p = .02
sBTN3g Median (ng/ml) Range	12.94 3.32–28.18	12.32 7.79–27.77	p = ns
sBTN3A1 Median (ng/ml) Range	6.84 2.03–24.76	11.03 5.11–24.76	p = .03
sBTN2A1 Median (ng/ml) Range	8.79 5.67–16.93	7.71 4.91–10.00	p = ns

*ANOVA test

Figure 2. PFS (months) to nivolumab treatment in mccRCC patients (a); mean value of plasmatic ICs levels in all nivolumab patients versus long-responders patients (>18 months) (b, c–f)

Figure 3. Kaplan-Meier analysis of progression free survival in patients from learning cohort with high and low plasma levels of sPD-1 (a), sPD-L1 (b), and sBTN3A1 (c)

Table 4. Association of sIC with best overall response by RECIST (BOR) and objective response of >20% (OR)

	Total pts (n.)	Best overall response by RECIST				Objective response
		RC/RP	SD	PD	p value*	>20%	<20%	p value*
PD-1 (ng/ml) ≤2.11 >2.11	13 8	1 6	8 1	4 1	<0.001	1 6	12 2	0.001
PD-L1 (ng/ml) ≤0.66 >0.66	10 11	2 6	5 4	4 1	ns	2 6	6 5	ns
sBTN2A1 (ng/ml) ≤6.01 >6.01	3 18	2 8	1 8	0 2	ns	2 8	1 10	ns
sBTN3A1 (ng/ml) ≤6.84 >6.84	11 10	1 7	6 2	4 1	0.015	1 7	10 3	0.004

*Pearson’s chi-square test

Table 5. Association between baseline plasma ICs levels and number of metastatic sites, localization of metastasis and IMDC Prognostic Risk Group

	Total pts (n.)	No. of metastatic sites			Site of metastasis			IMDC Prognostic Risk Group
		≤2	≥3	p value*	Lung	Others	p value*	Favorable	Intermediate	p value*
PD-1 (ng/ml) ≤2.11 >2.11	13 8	4 0	9 8	ns	5 1	8 7	ns	4 2	9 6	ns
PD-L1 (ng/ml) ≤0.66 >0.66	10 11	4 0	6 11	0.03	6 0	4 11	0.003	6 0	4 11	0.003
sBTN2A1(ng/ml) ≤6.01 >6.01	3 18	3 1	0 17	0.003	3 3	0 15	0.01	2 4	1 14	ns
sBTN3A1(ng/ml) ≤6.84 >6.84	11 10	4 0	7 10	ns	4 2	7 8	ns	5 1	6 9	ns

* Fisher’s exact test

Figure 4. Comparison T0-T1 of ICs levels in the plasma of mccRCC long responders patients treated with nivolumab

Figure 5. ICs in RCC patients: localized vs metastatic disease at baseline (pretreatment)