Merck licenses KRAS G12D cancer drug from SciBrunch for $400 million upfront

On September 28, 2026, Merck agreed to pay Shanghai-based SciBrunch Therapeutics $400 million upfront, with potential milestones reaching $2.13 billion, for global rights to the preclinical KRAS G12D inhibitor SPR2015. The deal highlights a growing trend of U.S. drugmakers licensing Chinese oncology assets. SPR2015 targets KRAS G12D, the most common RAS mutation in cancers, entering Merck into a highly competitive development landscape alongside rivals like Revolution Medicines.

Terms of the licensing agreement

• ▪The licensing agreement for SPR2015 could reach a total payout of up to $2.13 billion for SciBrunch Therapeutics if certain milestones are achieved
• ▪Merck agreed on September 28, 2026, to pay Shanghai-based SciBrunch Therapeutics $400 million upfront for global rights to develop and commercialize the preclinical cancer drug candidate SPR2015

Preclinical profile of SPR2015

• ▪Preclinical data presented in April 2026 at the American Association for Cancer Research annual meeting showed that SciBrunch Therapeutics' drug candidate SPR2015 administered as a monotherapy led to significant anti-tumor efficacy against colorectal cancer
• ▪SPR2015 is a preclinical small molecule drug candidate designed to block the KRAS G12D protein, which is associated with many types of cancer

Mechanism of RAS mutations

• ▪KRAS G12D is the most common RAS mutation found in human cancers
• ▪Mutated RAS proteins act like an on/off switch stuck in the "on" position, continuously sending cell proliferation signals that drive cancer growth

Competition in the KRAS inhibitor market

• ▪Merck's licensing of SPR2015 enters Merck into competition with Revolution Medicines' zoldonrasib, BridgeBio Oncology's BBO-11818, and Verastem Oncology's VS-7375, which are all targeting KRAS G12D
• ▪Merck is already developing MK-1084, an inhibitor of KRAS G12C proteins in the "off" state, which is in late-stage clinical testing for colorectal and non-small cell lung cancers
• ▪The first marketed RAS inhibitors, developed by Amgen and Bristol Myers Squibb, block the KRAS G12C variant, while Revolution Medicines recently won FDA approval for Rasonque to block multiple RAS variants

SciBrunch Therapeutics background and funding

• ▪SciBrunch Therapeutics was founded in 2024 by CEO Tao Hu, a veteran of Wuxi AppTec who previously sold a different KRAS G12D inhibitor to AstraZeneca in 2023
• ▪SciBrunch Therapeutics announced the close of $35 million in financing in January 2026, bringing the company's total raised to $65 million to support clinical development of its drug pipeline

US licensing of Chinese medicines

• ▪Chinese biotechnology companies frequently retain domestic rights to their drugs while licensing overseas rights in exchange for upfront payments, milestone payments, and royalties
• ▪Merck's agreement with SciBrunch Therapeutics on September 28, 2026, makes Merck the latest United States drugmaker to license China-developed medicines