China's Centre for Drug Evaluation (CDE) granted breakthrough therapy designation (BTD) on 7 July to Chia Tai Tianqing's TQB2102, an HER2-targeting bispecific antibody-drug conjugate (ADC), for neoadjuvant treatment of HER2-positive early or locally advanced breast cancer. TQB2102 combines a humanised HER2 IgG1 bispecific antibody with a topoisomerase I inhibitor payload (drug-to-antibody ratio 6). Phase II data presented this year showed 76.9% total pathological complete response (tpCR) in the 6 mg/kg cohort (n=26), surpassing standard chemo/dual-target therapy (56-66% tpCR).

The ADC also demonstrated activity in HER2-low breast cancer (53.4% objective response rate [ORR] in Phase Ib) and HER2-positive solid tumours (41.2% ORR in Phase I). Three HER2 bispecific ADCs are in global development, with TQB2102 initiating four Phase III trials since August 2024. The therapy maintains a manageable safety profile, with no interstitial lung disease reported.