NextCure, Inc. (Nasdaq: NXTC) and Simcere Zaiming have announced a strategic partnership to develop SIM0505, a novel antibody-drug conjugate (ADC) targeting CDH6 for the treatment of solid tumors. Under the agreement, NextCure gains global development and commercialization rights excluding Greater China, where Simcere Zaiming will retain rights.
Novel CDH6-Targeting ADC Platform
SIM0505 is directed to CDH6 (cadherin-6 or K-cadherin), described as a promising anti-tumor target, using a unique binding epitope with increased tumor binding compared to competing candidates. The ADC 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, according to the companies.
Clinical Development Timeline
SIM0505 is currently in Phase 1 dose escalation studies in China. NextCure expects to begin clinical testing in the United States in the third quarter of 2025, following clearance of an Investigational New Drug application by the U.S. Food and Drug Administration. Initial Phase 1 clinical data is expected in the first half of 2026.
A global dose expansion study is planned following the dose escalation portion of the study to include multiple tumor types.
Partnership Terms and Technology Access
The partnership includes substantial financial terms, with Simcere Zaiming eligible to receive payments throughout potential development phases, including upfront payment, development, regulatory and sales milestones up to $745 million, as well as tiered royalties up to double digits on net sales outside of the Greater China territory.
Additionally, NextCure gains access to Simcere Zaiming's proprietary linker and TOPOi payload for use in an ADC directed to a NextCure novel target, with Simcere Zaiming retaining Greater China rights to this additional novel target ADC.
Executive Perspectives
"We believe SIM0505 has the potential to be an important new therapy for cancer patients. Partnering with Simcere Zaiming, a leader in antibody-drug conjugates, provides us with an opportunity to advance a class-leading ADC directed to CDH6," said Michael Richman, NextCure's president and CEO. "Their proprietary payload is a potent cytotoxin with a potentially improved safety and efficacy profile compared to other topoisomerase inhibitors."
Renhong Tang, PhD, CEO of Simcere Zaiming, stated: "SIM0505 is a significantly differentiated CDH6 targeting ADC candidate independently developed by Simcere Zaiming. Our alliance reflects NextCure's recognition of our proprietary ADC platform, and together, we aim to accelerate drug development to benefit more cancer patients worldwide."
Company Backgrounds
NextCure is a clinical-stage biopharmaceutical company focused on advancing innovative medicines for cancer patients who do not respond to or have disease progression on current therapies, through differentiated mechanisms of action including antibody-drug conjugates.
Simcere Zaiming, founded in 2023, is an oncology-focused biopharmaceutical company and subsidiary of Simcere Pharmaceutical Group Limited (HKEX: 2096). The company has successfully launched several innovative products in China, including COSELA®, Enweida®, Endostar®, and Enlituo®.
