Merck & Co. will pay Shanghai-based SciBrunch Therapeutics $400 million upfront — and up to $2.13 billion in milestone payments — for exclusive global rights to SPR2015, a preclinical oral molecular glue targeting KRAS G12D (ON). The transaction has closed, and Merck will record the $400 million as a pre-tax charge, approximately $0.13 per share, in its third-quarter GAAP and non-GAAP results.

For that money, Merck acquires a candidate that has never entered human trials. SciBrunch describes SPR2015 as an oral KRAS G12D (ON) inhibitor in development for colorectal cancer (CRC), non-small cell lung cancer (NSCLC), and pancreatic ductal adenocarcinoma (PDAC). KRAS G12D is the most common oncogenic RAS mutation in human tumors, with 38% prevalence across pancreatic cancer, CRC, and NSCLC, according to a 2023 study. The mutation substitutes glycine with aspartate at position 12, leaving KRAS constitutively active and signaling for cell proliferation and survival.

The preclinical evidence

SciBrunch reported nanomolar antiproliferative activity for SPR2015 across KRAS G12D-mutant cell lines, with selectivity retained over KRAS wildtype cells. At the 2026 AACR Annual Meeting, a team including founder, chairman, and CEO Tao Hu, PhD, presented data from multiple in vivo cell-derived and patient-derived xenograft models.

"SPR2015 is a highly potent and selective KRAS G12D (on) inhibitor with nanomolar proliferation inhibitory activities in various KRAS G12D cell lines while with good selectivity over KRAS wild type," Hu and colleagues wrote in a poster presentation.

The headline number comes from a head-to-head mouse study: a single oral once-daily 100 mg/kg dose of SPR2015, compared against an unspecified G12D (ON) inhibitor in more than 15 CRC CDX and PDX models, produced a 64.7% objective response rate and 94.1% disease control rate as monotherapy. The comparator's identity remains undisclosed — a detail R&D evaluators will want clarified.

At the poster presentation, SciBrunch expected SPR2015 to enter human Phase I studies by the end of this year. In the deal announcement, neither company disclosed a current timeframe.

The competitive gap

SPR2015 starts behind. Sreyashi Paul, PhD, business analyst with Lucidquest Ventures, framed the core diligence question on the firm's website: "The diligence question is whether those properties survive translation into humans strongly enough to compensate for SPR2015's later start."

Paul cited the benchmark SPR2015 must beat: Revolution Medicines' zoldonrasib (RMC-9805), which posted a 52% confirmed ORR and 93% disease control rate in 27 efficacy-evaluable previously treated KRAS G12D NSCLC patients, reported in May. Verastem's VS-7375 has also produced early human data in the Phase I/II TARGET-D 101 trial (NCT07020221). In June, Verastem reported Phase I/II data (NCT06162221) showing 13 of 14 heavily pretreated metastatic PDAC patients on 900 mg once-daily monotherapy achieved greater than 50% reductions in the tumor marker CA19-9.

Strategic context

For Merck, the deal serves two portfolio needs: external innovation from Chinese biotechs, and pipeline rebuilding ahead of Keytruda's 2028 U.S. patent expiry. Keytruda (pembrolizumab) generated $15.81 billion in Q1–Q2 2026 sales on top of $31.641 billion last year, excluding $590 million from the subcutaneous Keytruda Qlex approved by FDA in September 2025. Wall Street consensus forecasts peak annual Keytruda revenue of roughly $33 billion by 2028.

Merck sees upside beyond replacement. Louise Chen, a managing director with Scotiabank, told Reuters the company has foreseen more than $70 billion of potential commercial opportunity by the mid-2030s.

"Evidence continues to accumulate for the therapeutic potential of targeting the KRAS pathway, a well-characterized factor in tumor cell growth," stated George Addona, senior vice president, discovery, preclinical development and translational medicine at Merck Research Laboratories. "This agreement complements and diversifies our expanding pipeline of precision targeted candidates with SPR2015, a potent engineered inhibitor for one of the most prevalent mutant forms of KRAS found in human cancers."

The seller

SciBrunch, founded in 2014 by Hu and CSO Yang Zhang, PhD, focuses on small molecule oncology therapeutics against clinically validated targets. In January, the company closed an oversubscribed Pre-A round above $35 million led by HighLight Capital, with participation from InnoPinnacle Fund, Hankang Capital, BioTrack Capital, LongRiver Investments, and Elikon Venture — bringing total capital raised to $65 million across two rounds. Proceedes were earmarked partly for IND-enabling studies of new-generation molecular glue RAS inhibitors.

"This agreement with Merck not only validates the R&D strength of our platform but also underscores the potential of SPR2015 in addressing longstanding unmet medical needs in oncology," Hu said. "We are excited that Merck, a global leader in oncology, will take SPR2015 forward."

SPR2015 is not the company's lead asset. That is SPR1020, a brain-penetrant PARP1 selective inhibitor in a Phase I/II first-in-human trial (NCT07359066) in advanced solid tumors, which dosed its first patient on January 8. SciBrunch predicts SPR1020 will show significant efficacy in tumors harboring BRCA mutations or homologous recombination repair pathway alterations — a projection the ongoing trial will now test.

Merck's next disclosure obligations on SPR2015 will come with its quarterly reporting; the industry will watch whether the Phase I start, once promised for this year, survives the transition to a new sponsor.