Table 1. Summary of features, activities, MTDs, and tumor PK of C188 and C188-9.

Features	C188	C188-9
Chemical Features
Structure
Log P	-	5.2
Solubility (μM)1	-	13.1
Inhibitory Activity (Mean ± SEM, n ≥ 2)
STAT3-pY peptide binding (SPR)	7.5 ± 3.5	2.5 ± 2.1
Ki	37.3 nM	12.4 nM
Ligand stimulated phosphorylation (Phosphoflow)
pSTAT3 (G-CSF)	16.8 ± 20.1	8.9 ± 5.8
pSTAT1 (IFNγ)	15.0 ± 0.0	9.5 ± 5.6
G-CSF Induced Phosphorylation (Luminex)
pSTAT3	16.2 ± 2.3	3.7 ± 1.9
pSTAT1	18.6 ± 4.7	4.1 ± 3.3
Constitutive pSTAT HNSCC cells
UM-SCC-17B
pSTAT3	15.4 ± 9.2	10.6 ± 0.7
Anchorage dependent growth (MTT)
UM-SCC-17B	6.3 ± 0.8	3.2 ± 0.6
MTD (mg/Kg/day)
Mice: 14 days	100	100
Plasma PK: IP and oral (10 mg/Kg)
Area under the curve (AUC, IP/oral, μg-hr/mL)	ND	12.5/12.5
Tumor PK: IP (10 mg/Kg; mouse)
Tumor level/plasma level (mg/ml [μM])2	ND	5.0 [10.4]/ 1.9 [4.0]
Tumor: Plasma ratio	ND	2.6

ND: Not Done; Cells used: G-CSF induced pSTAT3 and IFN-γ induced pSTAT1 by Phosphoflow: Kasumi-1, G-CSF induced pSTAT/GAPDH by Luminex (Kasumi1),

¹60 min at 37°C in PBS, pH 7.4,

²Tumor and plasma harvested 1 hr following IP dose.