NextCure tanks as it teams up with Simcere on novel ADC

Shares of USA-based NextCure (Nasdaq: NXTC) slumped 26% to $0.50 on Monday, after the company announced a strategic partnership with China-based Simcere Zaiming, subsidiary of Simcere Pharmaceutical Group Ltd (HKEX: 2096) to develop a therapy for the treatment of solid tumors.

The companies will partner on the development of SIM0505, a novel antibody-drug conjugate (ADC) targeting CDH6 (cadherin-6 or K-cadherin) for the treatment of solid tumors. SIM0505 is currently in Phase I clinical testing in China; NextCure expects to begin clinical testing in the USA in the third quarter of 2025.

SIM0505 is a novel ADC developed by Simcere Zaiming. It is directed to CDH6, a promising anti-tumor target, using a unique binding epitope with increased tumor binding compared to competing candidates. It also features Simcere Zaiming’s proprietary topoisomerase 1 inhibitor (TOPOi) payload, designed for broad anti-tumor activity while offering high systemic clearance to enlarge the therapeutic window. Preclinical studies have demonstrated robust anti-tumor activity across multiple solid tumor models and a promising safety profile in toxicology models.