At the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting, held in Chicago, USA, from May 30 to June 3, 7MW3711, a novel B7-H3 targeting ADC, and 9MW2921, a novel Trop-2 targeting ADC, presented clinical study results in poster sessions.

B7-H3 ADC (7MW3711)

In the phase I/II clinical study in patients with advanced solid tumors, 49 patients has been enrolled as of April 23, 2025. During the dose-escalation phase, dose-limiting toxicity (DLT) was not observed and the maximum tolerated dose (MTD) has not been reached. In assessable patients at doses of 4.5 mg/kg or higher (Q3W), the ORR for esophageal cancer (6 cases), ovarian cancer (5 cases), and prostate cancer (4 cases) was 33.3%, 60.0%, and 50.0%, respectively, and the DCR was 100%. In assessable patients at doses of 4.0 mg/kg (Q2W), the ORR for the small cell lung cancer (7 cases) and squamous lung cancer (2 cases) were 57.1% and 50.0%, respectively, and the DCR were 85.7% and 100.0%, respectively.

In the phase I/II clinical study in lung cancer patients, 37 patients were enrolled as of January 8, 2025, including 16 small cell lung cancer (SCLC) patients and 21 non-small cell lung cancer (NSCLC) patients. Common grade ≥3 adverse reactions were neutrophil count decreased, white blood cell count decreased, anemia, white blood cell count decreased, and platelet count decreased. The ORR and DCR were 62.5% and 100.0%, respectively, among 8 assessable patients with small-cell lung cancer at a dose of 4.5 mg/kg. The ORR and DCR were 37.5% and 87.5%, respectively, among 8 assessable patients of squamous lung cancer (Sq-NSCLC) with a B7-H3 H-score >5.

The study results suggest that 7MW3711 has a tolerable safety profile and good anti-tumor activity in patients with advanced tumors such as lung, esophageal, prostate and ovarian cancers.

Trop-2 ADC (9MW2921)

In the first-in-human clinical study in patients with advanced solid tumors, a total of 39 patients were enrolled as of November 12, 2024. The most common ≥3 grade adverse were stomatitis, anemia, white blood cell count decreased, neutropenia, white blood cell count decreased, etc. At a dose of 3.0 mg/kg, the ORR was 42.1% and the DCR was 84.2%. Under this dose level, the ORR and DCR was 75% and 100% for endometrial cancer (4 cases), 50% and 75% for HR+/HER2- breast cancer (4 cases), 50% and 100% for gastric cancer (4 cases), 25% and 100% for non-squamous non-small cell lung cancer (4 cases).

The study result suggests that 9MW2921 has a tolerable safety profile and good anti-tumor activity in patients with advanced tumors.

About 7MW3711

7MW3711 was developed with Mabwell's Interchain-Disulfide Drug Conjugate (IDDC™) platform. It consists of an innovative antibody molecule, a novel linker, and a novel payload Mtoxin™, which is a topoisomerase I inhibitor. It has been granted Orphan Drug Designation (ODD) by the FDA for the treatment of SCLC.

About 9MW2921

9MW2921 was developed with Mabwell's Interchain-Disulfide Drug Conjugate (IDDC™) platform. It consists of an innovative antibody molecule, a novel linker, and a novel payload Mtoxin™, which is a topoisomerase I inhibitor.