Phrontline Biopharma Highlights Encouraging Preliminary Safety and Antitumor Activity of TJ101 Presented at ESMO 2026 and Announces Phase Ib Initiation

Preliminary responses observed in 6 of 8 evaluable urothelial carcinoma patients (75%), including patients previously treated with enfortumab vedotin and pembrolizumab

Early antitumor activity also observed in squamous NSCLC, SCLC and prostate cancer

SHANGHAI and HANGZHOU, China, Oct. 29, 2026 /PRNewswire/ -- Phrontline Biopharma, a clinical-stage biotechnology company developing next-generation antibody-drug conjugates (ADCs), today highlighted encouraging preliminary clinical results for TJ101 presented at the European Society for Medical Oncology (ESMO) Congress 2026 in Madrid, Spain, on October 23, 2026. 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 antitumor activity across multiple advanced solid tumors.

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

The emerging safety and tolerability findings support continued clinical evaluation, with ongoing dose escalation and exploration of alternative treatment schedules aimed at optimizing the therapeutic potential of TJ101.

"We are encouraged by the emerging safety profile and preliminary antitumor activity of TJ101, particularly in urothelial carcinoma and NSCLC," said Martín Sebastian Olivo, MD, MSc, Chief Medical Officer of Phrontline Biopharma. "The responses observed in patients previously treated with EV and pembrolizumab are especially promising as we continue to optimize dosing and treatment schedules."

About TJ101

TJ101 is an investigational EGFR × B7-H3 bispecific ADC incorporating a topoisomerase I inhibitor payload. It is being evaluated in an ongoing global Phase I study in patients with advanced solid tumors. TJ101 has not been approved by any regulatory authority, and its safety and efficacy have not been established.

About Phrontline Biopharma

Phrontline Biopharma is a clinical-stage biotechnology company headquartered in Hangzhou, China, developing next-generation ADCs for solid tumors. Its proprietary platform combines bispecific antibody engineering, multiple payload mechanisms and branched dual-payload linker technology to address tumor heterogeneity and treatment resistance.

For more information, visit www.phrontlinebio.com.

Forward-Looking Statements

This release contains forward-looking statements regarding TJ101's clinical development and potential benefits. Actual results may differ materially due to risks inherent in drug development. Preliminary findings from limited patient numbers may not predict outcomes in subsequent studies. Phrontline undertakes no obligation to update these statements except as required by law.

SOURCE Phrontline Biopharma