Figure S1: In vitro kinetics of SYD985. Total antibody concentration during 96-hour incubation of 100 mg/mL SYD985 at 37°C in human, monkey, rat and mouse plasma (mean +/- SEM). Figure S2: Ion trap MS/MS fragmentation spectrum (HCD @30 eV) of three SYD985-CES1c cross-linked peptide structures (all precursor ions were 3+) Figure S3: A, Conjugated antibody concentrations in female BALB/c mice after a single IV bolus injection of 1 and 5 mg/kg SYD985 in combination with an intraperitoneal injection of 150 mg/kg BNPP, 15 minutes prior to SYD985 dosing (mean +/- SEM, n=3). B, Conjugated antibody concentrations in female BALB/c mice after a single IV bolus injection of 5 mg/kg SYD985 in combination with increasing subcutaneous dosages of CBDP, 60 minutes prior to SYD985 dosing (mean +/- SEM, n=3). Figure S4: Anti-tumor activity of SYD985 compared to vehicle control in the breast cancer PDX models MAXF449. Table S1: ADC pharmacokinetic parameters in CES1c transgenic mice mice after a single i.v. bolus injection of 5 mg/kg SYD985. Table S2: IC50 and efficacy values of cytotoxic activity presented in Figure 1E. Table S3: Comparison of SYD985 conjugated antibody PK parameters in MAXF1162 tumor bearing CES1c -/- SCID mice with the PK in human.