Table 1.

CD25-positive and -negative cell lines were incubated with increasing concentrations of ADCT-301 or free warhead (SG3199) for 96 hours before processing by the MTS assay

Mean CD25GI50
Cell lineTumor typemolecules per cell surface (thousands)ADCT-301 ng/mL (pmol/L)SG3199 pmol/L
Su-DHL-1ALCL3100.74 (4.96)12.11
HDLM-2HL1672.94 (19.60)158.60
L-540HL961.11 (7.49)14.80
Karpas 299ALCL772.56 (17.07)18.49
RamosBurkitt<1a>1,000 (>6,667)5.83
DaudiBurkitt<1a>1,000 (>6,667)18.11
HuT-78CTCL<1a>1,000 (>6,667)12.98
EoL-1AML170.04 (0.26)0.79
KG-1AML<1a>1,000 (>6,667)NDb
  • NOTE: Data for each cell line are presented as the GI50, that is, 50% of the net tetrazolium reduction product increase in untreated cells. The mean number of CD25 molecules per cell line was determined by flow cytometric analysis using Qifikit (DAKO).

  • Abbreviation: ALCL, anaplastic large cell lymphoma; AML, acute myeloid leukemia; CTCL, cutaneous T cell lymphoma; HL, Hodgkin lymphoma.

  • a1,000 reflects the limits of sensitivity of this assay below which cell lines were considered CD25 negative.

  • bNot determined.