GC Cell and Artiva Biotherapeutics have terminated their collaboration agreement with global pharmaceutical giant Merck Sharp & Dohme Corp. (MSD) to develop CAR-NK solid tumor treatments. GC Cell revealed it in a public filing on Tuesday.

In January 2021, the then GC Lab Cell signed an agreement with MSD to co-develop three CAR-NK (Chimeric Antigen Receptor-Natural Killer) cell therapies targeting solid tumors with its affiliate Artiva Biotherapeutics.

The deal drew the industry’s attention with a total upfront payment of $1.86 billion (about 2.59 trillion won). Of the total upfront payment, GC Cell was to receive a non-refundable upfront payment of $15 million and milestone payments of $966.5 million, which included running royalties in proportion to net sales upon development and approval.

At the time of the agreement's conclusion, GC Cell emphasized that the deal was viewed as a technology export of the original platform, as opposed to the more common practice of licensing out a specific drug candidate, and that it was highly unusual for a global pharmaceutical company to value the CAR-NK platform technology in trillions of won.

According to the disclosure, the termination was based on MSD's internal decision. MSD terminated the collaborative R&D agreement with Artiva, and Artiva notified GC Cell of the termination.

Despite the termination, GC Cell said it is not obligated to return the $15 million upfront payment because it completed “research work” during the term of the agreement.

GC Cell and Artiva Biotherapeutics are jointly developing CAR-NK cell therapies, including AB-201, which targets HER2.