Phrontline Biopharma, a clinical-stage biotechnology company developing next-generation antibody-drug conjugates (ADCs), on Thursday reported encouraging preliminary clinical results for TJ101 presented at the European Society for Medical Oncology (ESMO) Congress 2026 in Madrid, Spain.

The company also announced the initiation of Phase Ib, with the first patient dosed.

TJ101 is an investigational bispecific ADC targeting EGFR and B7-H3, incorporating a topoisomerase I inhibitor payload. The ESMO presentation highlighted its emerging safety and tolerability profile and preliminary antitumour activity across multiple advanced solid tumours.

Among eight response-evaluable patients with urothelial carcinoma, six achieved partial responses (75%), including patients previously treated with enfortumab vedotin (EV) and pembrolizumab. Preliminary antitumour activity was also observed in other solid tumours, including squamous non-small cell lung cancer (sqNSCLC), small cell lung cancer (SCLC) and prostate cancer, supporting further clinical investigation across these indications.

Phrontline Biopharma said that the emerging safety and tolerability findings support continued clinical evaluation, with ongoing dose escalation and exploration of alternative treatment schedules aimed at optimising the therapeutic potential of TJ101.