Merck Discontinues In-House TROP2 ADC MK-6837 After Revealing Dual Development Strategy
核心洞察
Merck & Co (搜索) has discontinued its internally developed TROP2 (搜索)-directed antibody-drug conjugate MK-6837, just three weeks after its mechanism was revealed through an Israeli clinical trial registry.
The company had been simultaneously developing MK-6837 alongside its licensed TROP2 (搜索) ADC sacituzumab tirumotecan from Kelun (搜索), creating an unusual dual development strategy for the same target.
Dean Li, president of Merck Research Laboratories, cited the "profound impact of sac-tmt" as one reason for abandoning MK-6837, which featured a unique payload design.
Merck & Co (搜索) has quietly discontinued its internally developed TROP2 (搜索)-directed antibody-drug conjugate MK-6837, just three weeks after the molecule's mechanism of action was revealed through an obscure Israeli clinical trial registry. The decision marks an abrupt end to an unusual dual development strategy that saw the pharmaceutical giant simultaneously advancing two ADCs targeting the same antigen.
The discontinuation was announced during Merck's first-quarter earnings call on Thursday, when Dean Li, president of Merck Research Laboratories, confirmed to analysts that "we have discontinued that" in response to questions about MK-6837. Li provided no detailed explanation for the decision but noted that MK-6837 was "another ADC, which had a unique payload."
Dual TROP2 Strategy Revealed
MK-6837 had been shrouded in secrecy since entering phase 1 clinical development in July 2024, with its main clinicaltrials.gov listing revealing nothing about its mechanism of action. The molecule's true nature only came to light in April through an Israeli clinical trial registry, which disclosed that "MK-6837 is a novel antibody-drug conjugate that binds to the tumour-associated antigen TROP2 (搜索)."
This revelation exposed Merck's unusual strategy of developing two TROP2 (搜索)-directed ADCs simultaneously. The company has been advancing sacituzumab tirumotecan (sac-tmt), licensed from Kelun (搜索) in 2022 for $47 million upfront, which is now enrolled in 17 pivotal studies seeking to recruit over 15,000 patients across numerous tumor types.
Strategic Implications and Questions
The parallel development of MK-6837 alongside sac-tmt raised questions about potential conflicts with Merck's licensing agreement with Kelun (搜索). While the details of the 2022 deal remain confidential, it appeared unusual that Merck was permitted to develop an in-house asset that would theoretically compete against the licensed molecule.
Li suggested that the decision to abandon MK-6837 was influenced by sac-tmt's performance, citing the "profound impact of sac-tmt" as one factor. He emphasized Merck's broader ADC strategy, stating: "We've always said that we're very interested in the ADC field in changing the target, but also changing the payload and thinking about combinatory [approaches] or cycling different payloads."
Kelun Partnership Remains Central
Despite the discontinuation of MK-6837, Merck's relationship with Kelun (搜索) appears to remain strong. The collaboration has expanded several times since the original sac-tmt transaction and now includes several other ADCs. Together with a major 2023 partnership with Daiichi Sankyo, Kelun serves as a key source of Merck's ADC expertise.
The importance of sac-tmt to Merck's oncology pipeline cannot be understated, given its extensive clinical development program spanning multiple tumor types. The molecule represents a cornerstone of Merck's ADC strategy, which may have ultimately made the parallel development of MK-6837 redundant.
While Merck declined to provide further details about MK-6837's design characteristics or the reasoning behind developing both ADCs, the discontinuation suggests the company is consolidating its TROP2 (搜索) efforts around the proven Kelun (搜索)-originated asset. Whether external pressure from Kelun influenced this decision remains unclear, as the Chinese company has not responded to requests for comment on the matter.