(Yicai) Oct. 12 -- Shares of MicuRx Pharmaceutical reversed an early surge of more than 9 percent today after the Chinese drugmaker announced a potential USD973 million licensing deal with a Swiss partner.

MicuRx [SHA: 688373] quickly erased its gains and closed 3.1 percent lower at CNY5.55 (US 80 cents) per share, falling below the price seen before the deal.

MicuRx plans to license its experimental cancer drug MRX-23 and proprietary development platform to Switzerland's ClearideBio Therapeutics, with potential milestone payments of USD973 million, according to a recent stock exchange filing.

Founded in 2007, MicuRx develops treatments for drug-resistant bacterial infections, with research centers in China and the United States. Its first antibiotic, contezolid, was approved in China in 2021.

MicuRx did not disclose which cancers MRX-23 is intended to treat. According to its 2025 annual report, released in August, MRX-23 is its first bispecific antibody-drug conjugate (ADC) candidate and remains in preclinical development. ADCs use antibodies to deliver cancer-killing drugs to tumor cells, potentially improving treatment effectiveness while limiting damage to healthy tissues. Bispecific ADCs are designed to recognize two targets, allowing for potentially more precise treatment.

Under the proposed licensing agreement, ClearideBio will obtain exclusive global rights to develop, manufacture, and commercialize MRX-23 for all indications, taking responsibility for bringing the drug to market.

The companies also plan a technology agreement under which ClearideBio can use MicuRx's STOPIN platform to develop ADCs with cancer-killing payloads designed to reduce toxicity, covering up to six additional targets or target combinations. The Swiss firm will gain exclusive global rights to each project after exercising its option and making the required payment.

Licensing Terms and Drug Development

Under the MRX-23 agreement, ClearideBio will pay MicuRx USD1 million upfront and up to USD223 million in research and development, regulatory, and sales milestone payments. These include USD3.5 million payable upon approval of the first clinical trial application for a licensed product.

Under the platform agreement, milestone payments could reach USD125 million per project, or USD750 million if ClearideBio exercises its options for all six projects.

ClearideBio will also pay royalties on drug sales, while MicuRx will receive a share of revenue if the Swiss firm sublicenses development rights to third parties.

Founded in December 2025 and based in Basel, ClearideBio develops next-generation ADC therapies, according to its website.

Editor: Emmi Laine