Background:

SPDB is a small fragment that can linked DM4 conjugates. Conjugated to antibodies utilizing disulfide linkers: anti-EGFR-SPDB-DM4 has been widely used.

[1]. Widdison WC et al. Development of Anilino-Maytansinoid ADCs that Efficiently Release Cytotoxic Metabolitesin Cancer Cells andInduce High Levels of Bystander Killing. Bioconjug Chem, 2015 Nov 18, 26(11):2261-78.