Fig 1.
Potency of hinge-cysteine thailanstatin trastuzumab ADC.
(A) Structure of iodoacetamide derivatized non-cleavable thailanstatin linker-payloads (LPs). (B) In vitro cytotoxicity of hinge-cysteine thailanstatin trastuzumab ADCs against cancer cell lines expressing various levels of Her2, reported in half-maximal inhibitory concentration (IC50) values of conjugated payload in nM. Data are the mean of multiple experiments. (C) In vivo efficacy of hinge-cysteine thailanstatin trastuzumab ADC1 in an N87 gastric cancer xenograft model dosed at 3 mg/kg (q4d x 4). Arrows indicate the day(s) on which intravenous dosing was carried out. DAR = Drug Antibody Ratio; 361 = MDA-MB-361-DYT2; 468 = MDA-MB-468.
Table 1.
In vitro cytotoxicity of single-cysteine mutant thailanstatin trastuzumab ADCs against various levels of Her2 expressing cancer cell lines, reported in Mean IC50 values of conjugated payload in nM.
Fig 2.
Generation of site-specific multiple-payload carrying peptidic linker (MPP) ADC delivering MMAD.
(A) Schematic showing generation of a double-MMAD carrying peptidic linker ADC generated on trastuzumab A114C. (B) In vitro cytotoxicity of peptidic linked MMAD trastuzumab A114C ADC against various levels of Her2 expressing cancer cell lines, reported in Mean IC50 values of conjugated payload in nM. Data are the mean of multiple experiments. MAL = malemide; DBCO = Dibenzocyclooctyne.
Fig 3.
Site-specific thailanstatin MPP ADCs.
(A) Preparation of thailanstatin MPP ADC from thailanstatin NHS ester (8). (B) In vitro cytotoxicity of site-specific thailanstatin MPP trastuzumab ADCs against various levels of Her2 expressing cancer cell lines, reported in Mean IC50 values of conjugated payload in nM. Data are the mean of multiple experiments. (C) In vivo efficacy of thailanstatin MPP trastuzumab ADCs (ADC 13 and ADC 14) in N87 gastric cancer xenograft model dosed at 3 mg/kg (q4d x 4). Arrows indicate the day(s) on which intravenous dosing was carried out.
Fig 4.
Double-cysteine mutant thailanstatin trastuzumab ADCs.
(A) In vitro cytotoxicity of double-cysteine mutant thailanstatin trastuzumab ADCs against various levels of Her2 expressing cancer cell lines, reported in Mean IC50 values of conjugated payload in nM. Data are the mean of multiple experiments. (B) In vivo efficacy of double-cysteine mutant thailanstatin trastuzumab ADC16 in N87 gastric cancer xenograft model dosed at 0.5, 1.56 and 3 mg/kg (q4d x 4). (C) In vitro cytotoxicity of double-cysteine mutant thailanstatin trastuzumab ADC16 against T-DM1 resistant N87 (N87-TDM1) and 361 (361-TDM1) as well as MDR1 overexpressing N87 (N87-MDR1-CL3) cancer cell lines, reported in IC50 values of conjugated payload in nM.