Table 2 Characteristics of the dogs at baseline.

 Median

13

 Range

8–16

Age category―no. (%)

 ≥10 year

27 (93.1)

 <10 year

2 (6.9)

Sex―no. (%)

 Male

     Intact

8 (27.6)

     Castrated

11 (37.9)

     All

19 (65.5)

 Female

     Intact

3 (10.3)

     Spayed

7 (24.1)

     All

10 (34.5)

PD-L1 status—no. (%)

  Positive

     TPS ≥ 50%

18 (62.1)

     TPS 1–49%

1 (3.4)

     TPS ND

7 (24.1)

     All

26 (89.7)

  Negative (TPS < 1%)

2 (6.9)

  ND

1 (3.4)

Prior therapy―no. (%)

  Surgery

17 (58.6)

  Radiation

     ≤8 weeks^a

8 (27.6)

     >8 weeks

4 (13.8)

     Unknown

2 (6.9)

     All

14 (48.3)

  Chemotherapy

1 (3.4)

  None

2 (6.9)

Measurable lesion(s)―no. (%)

     Present

13 (44.8)

     Absent

16 (55.2)