NextCure Signs $745 Million Licensing Agreement for SIM0505 with Simcere Zaiming

NextCure has signed a licensing deal valued at up to $745 million for the rights outside Greater China to Simcere Zaiming’s experimental cancer therapy, SIM0505. The agreement is part of NextCure’s ongoing transition toward developing antibody-drug conjugates (ADCs) and includes milestone-based payments as well as royalties on potential future sales.

SIM0505 is a CDH6-targeted ADC currently undergoing phase 1 evaluation in China. The experimental treatment is being tested by Simcere in an ongoing early-stage clinical trial. NextCure plans to begin its own clinical trial of SIM0505 in the United States in the third quarter of 2025.

The design of SIM0505 involves combining a CDH6-targeting antibody with a topoisomerase 1 inhibitor (TOPOi) payload. According to NextCure’s June 16 release, this combination is intended to provide “broad anti-tumor activity while offering high systemic clearance to enlarge the therapeutic window.” Simcere is eligible to receive a total of up to $745 million in upfront, development, regulatory, and commercial milestone payments. Although the exact breakdown of the payments was not disclosed, Simcere may also receive tiered royalties should the product reach the market outside of Greater China.

Under the terms of the deal, NextCure also obtains access to Simcere’s proprietary linker and TOPOi payload technology. This access will enable NextCure to develop a separate, undisclosed preclinical ADC program. In this case, Simcere will retain rights within the Greater China region.

The licensing arrangement follows a strategic decision by NextCure in November 2024 to concentrate its resources on ADCs. This involved deprioritizing its clinical-stage LAIR-2 Fc fusion protein candidate, NC410, in favor of a preclinical ADC targeting B7-H4. That preclinical candidate has since progressed into clinical development.

NextCure’s Chief Executive Officer, Michael Richman, commented on the significance of the agreement. “We believe SIM0505 has the potential to be an important new therapy for cancer patients,” Richman said. He added, “Partnering with Simcere Zaiming, a leader in antibody-drug conjugates, provides us with an opportunity to advance a class-leading ADC directed to CDH6. Their proprietary payload is a potent cytotoxin with a potentially improved safety and efficacy profile compared to other topoisomerase inhibitors.”

Simcere’s portfolio includes multiple oncology drugs in the Chinese market. These include treatments such as Cosela, which has received FDA approval, and Enweida, which is used for biliary tract cancer. In early 2025, Simcere also entered into a separate licensing deal worth up to $1 billion focused on a phase 1-stage trispecific antibody with another company.

Initial data from Simcere’s ongoing SIM0505 clinical trial is expected in the first half of next year. Meanwhile, NextCure is preparing to initiate its own evaluation of the drug in the U.S., scheduled to begin in the third quarter of 2025.