Table 1.

General Patient Characteristics (IAE’s = Immune-related Adverse Events)

Variables	Cohort A (No Metformin) N = 33 (60%)	Cohort B (Metformin) N = 22 (40%)
Mean Age at Diagnosis (Years)	60.8 ± 15.3	67.4 ± 12.6	P = 0.08
Sex
Male	19 (57.6%)	15 (68.2%)	P = 0.42
Female	14 (42.4%)	7 (31.8%)
Dead	11 (36.4%)	5 (22.7%)	P = 0.28
TNM Stage
IIIC	2 (6%)	0 (0%)
IV	31 (94%)	22 (100%)	P = 0.23
BRAF Mutations	14 (58.3%)	11 (73.3%)	P = 0.34
NRAS Mutations	5 (21.7%)	4 (26.7%)	P = 0.67
Mean no. of mutations	1.3 ± 0.8	1.46 ± 0.9	P = 0.67
History of Diabetes	1 (3%)	17 (77.3%)	P < 0.001
Median Metformin Dose		500 mg BID (Range 500 mg BID – 1000 mg BID)
Median duration of Metformin Therapy (Months)		13.5 (0.5–108.7)
Radiation therapy	6 (18.2%)	2 (9%)	P = 0.34
Prior Chemo/Immunotherapy	14 (42.4%)	9 (40.9%)	P = 0.91
Immunotherapy
Anti- PD-1 (Pembrolizumab, Nivolumab)	20 (60.6%)	14 (63.6%)	P = 0.93
Ipilimumab/Nivolumab	9 (27.2%)	6 (27.3%)
Ipilimumab	4 (12.1%)	2 (9.1%)
Progression	20 (60.6%)	10 (45.4%)	P = 0.26
Mean number of metastatic site involved before starting therapy	2.54 ± 1	2.36± 0.95	P = 0.5
Mean number of new metastatic site appeared while on therapy	1.51±1.5	0.59± 0.5	P = 0.009
Skeletal Metastasis
Before therapy	7 (21.2%)	4 (18.2%)	P = 0.78
During Therapy	6 (18.2%)	3 (13.6%)	P = 0.69
Brain Metastasis
Before therapy	6 (18.2%)	2 (9%)	P = 0.34
New brain metastasis during therapy	5 (15.2%)	1 (4.5%)	P = 0.21
IAE	20 (60%)	13 (59%)	P = 0.91
Prednisone required for IAE’s	18 (54.5%)	13 (59%)	P = 0.73
Performance Status
0	12 (36.4%)	11 (50%)	P = 0.33
1	14 (42.4%)	8 (36.4%)
2	7 (21.2%)	2 (9.1%)
3	0 (0%)	1 (4.5%)