Table 1.

Cell lines from multiple tumor types are sensitive to RN927C

Cell nameTumor typeTrop-2 expression (receptor #)RN927C IC50 (nmol/L)Neg ctrl-ADC IC50 (nmol/L)PF-06380101 IC50 (nmol/L)
A431Epidermoid+++ (700,000)0.202 ± 0.050248.7
FaduPharynx squamous+++ (387,000)0.507 ± 0.219>2670.683 ± 0.066
BxPC3Pancreas++/+++ (137,000)0.674 ± 0.286>2670.116 ± 0.034
HCC-827Lung++/+++0.779 ± 0.328>267
NCI-H1650Lung++ (100,000)1.920>267
Colo205Colorectal+/++ (50,000)50.6 ± 22.5ND
SW620Colorectal>267>2670.305 ± 0.046
  • NOTE: Cytotoxicity assay of RN927C on a panel of tumor cells from different cancer types was performed as described in Materials and Methods. Trop-2 expression (number of + symbols) levels were empirically assigned on the basis of staining intensity of RN927C parent Ab by FACS (data not shown) and corresponded to the following receptor copy number ranges: +, ≤10–50,000; ++, 50–100,000; +++, ≥100,000. For A431, Fadu, BxPC3, NCI-H1650, and Colo205 cells, the actual receptor numbers are listed in parentheses. For A431, Fadu, BxPC3, HCC-827, and Colo205 cells, the inhibitory concentration of 50% (IC50) was calculated by logistic nonlinear regression and is reported as the mean ± SD in nmol/L of antibody concentration from multiple experiments. For SW620, no average can be calculated as most IC50 values from various experiments exceeded the top concentration of 267 nmol/L. Only single experimental value was listed for OVCAR3, RL95-2, Calu-3, NCI-H292, NCI-H1650, MDA-MB-468, and SKBR3 cells. Free payload PF-06380101 was tested on tumor cell lines BxPC3, SW620, and Fadu tumor cells. Note that Trop-2 cell SW620 is sensitive to free payload killing.

  • Abbreviations: ND, not determined; Neg ctrl, negative control.