Alphamab Oncology announced that data from the clinical study conducted in China (JSKN003-102) of anti-HER2 bispecific antibody-drug conjugate (ADC) JSKN003 for the treatment of HER2-expressing advanced solid tumors, were presented for the first time at the 2024 Annual Meeting of American Society of Clinical Oncology (2024 ASCO Annual Meeting). Title: Evaluation of the safety, pharmacokinetics, and efficacy of JSKN003 in patients with advanced solid tumors: A phase I/II clinical study. JSKN003, an anti-HER2 bispespecific antibody-drug conjugate ("bis-ADC), developed inhouse with proprietary Glycan-specific conjugation platform, shows better serum stability which may lead to a broader therapeutic window.

The data of the phase I clinical trial conducted in Australia presented at the 2024 Annual Meeting ofAmerican Association for Cancer Research (AACR) in April demonstrated favorable tolerability, safety profile and encouraging preliminary anti-tumor activity. Multiple clinical studies of JSKN003 are currently being conducted in Australia and China, and are also actively making the progress in its pivotal clinical trial in advanced HER2 low-expression breast cancer in China. M M&S: JSKN003-102 (NCT05744427) is a phase I (dose escalation and expansion) and phase II (cohort expansion) clinical study in Chinese patients with advanced solid tumors.

Patients with confirmed pathological records of unresectable locally advanced or metastatic solid tumors with HER2 expression (IHC1+) or gene mutation (HER2 exon 19 or 20 mutation) who failed standard therapy, cannot tolerate standard therapy, or lack of effective treatment were enrolled. The objectives were safety, pharmacokinetics (PK), preliminary antitumor activity of JSKN003 and to determine the maximum tolerated dose (MTD) or the recommended phase II dose (RP2D). Dose-escalation part adopts BOIN design across 7 dose levels (1.0 - 8.4 mg/kg, Q3W).

Results from April 5, 2024, 46 patients (25 breast cancers, 11 gastric cancers, 8 colorectal cancers, 1 lung cancer, and 1 ovarian cancer) were enrolled and received JSKN003 across 6 dose levels (2.1 - 8.4mg/kg, Q3W) in phase I part (1.0mg/kg was exempted). For breast cancer, the ORR was 73.3% in 15 HER2 positive patients and 33.3% in 9 HER2 low patients, respectively. JSKN003 is an anti-HER2 bis pecific antibody-drug conjugated (bis-ADC), which is developed inhouse with proprietary Gly can-specific conjugation platform.

JSKN003 targets HER2 and triggers internalization and release the cytotoxic drug. Compared with its counterparts, JSKN003 demonstrated better serum stability, stronger byer effect and comparable tumor killing activity, which effectively expands the therapeutic window. Multiple clinical studies of J SKN003 are currently being conducted In Australia and China, and are already actively making the progress in its Phase I clinical trial in advanced HER 2 low- expression in China.