Table 1.

Antibody-drug conjugates approved for the treatment of HER2-positive breast cancer as of February 2023

ADC	Trade name	Target antigen	Antibody	Payload	Linker	Average DAR	Developer	Approved date	Approved indications
Trastuzumab emtansine (ado-trastuzumab emtansine; T-DM1)	Kadcyla	HER2	humanized IgG1 (trastuzumab)	DM1	non-cleavable (SMCC)	3.5	Genentech	February 2013	Patients with HER2-positive metastatic breast cancer who have received prior treatment with trastuzumab and a taxane, separately or in combination
								May 2019	The adjuvant treatment of patients with HER2-positive early breast cancer who have residual invasive disease after neoadjuvant taxane and trastuzumab-based treatment
Trastuzumab deruxtecan (fam-trastuzumab deruxtecan-nxki; T-DXd; DS8201a)	Enhertu	HER2	humanized IgG1 (MAAL-9001)	DXd	cleavable (maleimide GGFG peptide)	7.0–8.0	Daiichi Sankyo	December 2019	adult patients with unresectable or metastatic HER2-positive breast cancer who have received two or more prior anti-HER2-based regimens in the metastatic setting (accelerated approval)
								May 2022	adult patients with unresectable or metastatic HER2-positive breast cancer who have received a prior anti-HER2-based regimen either in the metastatic setting, or in the neoadjuvant or adjuvant setting, and have developed disease recurrence during or within 6 months of completing therapy

HER2, human epidermal growth factor receptor 2; ADC, antibody-drug conjugate; DAR, drug-to-antibody ratio; SMCC, succinimidyl trans-4-(maleimidylmethyl)cyclohexane-1-carboxylate; GGFG, glycine-glycine-phenylalanine-glycine.