Daiichi Sankyo’s Next Lung Cancer Bet: What the New Merck Partnership Study Means for Investors

Daiichi Sankyo Company (DSKYF) announced an update on their ongoing clinical study.

Study Overview
This study, officially titled “KEYMAKER-U01 Substudy 01F: A Phase 1b/2 Umbrella Study With Rolling Arms of Investigational Agents for Previously Treated Participants With Advanced or Metastatic Nonsquamous Non-small Cell Lung Cancer (NSCLC) With KRAS G12C Mutations,” aims to test new drug combinations in patients whose lung cancer has already been treated but has come back or spread. The main goals are to see how safe these combinations are and how well they shrink or clear tumors, in a group of patients with a specific KRAS G12C mutation that is drawing strong interest from oncology drug developers.

Intervention/Treatment
The study tests MK-1084, an oral targeted cancer drug, in combination with three different antibody-based medicines: patritumab deruxtecan (HER3-DXd), sacituzumab tirumotecan (Sac-TMT), and cetuximab. These combinations are designed to attack cancer cells in different ways, aiming to improve responses in hard-to-treat lung cancer while keeping side effects manageable.

Study Design
This is an interventional Phase 1b/2 trial with randomized assignment. Patients first enter a dose-escalation stage, where the study team increases doses step by step to find safe levels. After that, eligible patients are placed in parallel treatment groups to compare the different combinations. The study is open-label, meaning doctors and patients know which treatment they receive. The main purpose is treatment, focusing on safety and tumor response rather than prevention or diagnosis.

Study Timeline
The study was first submitted on 17 November 2025, signaling the start of regulatory and site-activation work. It is listed as “Not yet recruiting,” so patient enrollment has not begun but is expected to follow. The latest update was submitted on 23 December 2025, indicating the protocol and operational plans have been recently reviewed and adjusted. Primary and final completion dates are not yet posted, which is typical for an early-stage, flexible umbrella design that may add or close treatment arms over time.

Market Implications
This update reinforces Merck’s and Daiichi Sankyo’s push into KRAS G12C lung cancer, an area already targeted by players such as Amgen and Mirati/Bristol Myers Squibb. For Daiichi Sankyo (DSKYF), inclusion of its antibody–drug conjugate patritumab deruxtecan as a key partner in this trial strengthens the company’s pipeline story in solid tumors beyond breast and gastric cancers. If early safety and response data trend positive, the news could support sentiment around Daiichi Sankyo’s oncology franchise, validate its platform for more partnerships, and justify premium valuations. However, investors should note that this is a Phase 1b/2 effort at a very early stage, so near-term revenue impact is limited and readouts are likely several years away. Competitive risk also remains high as multiple KRAS G12C and antibody–drug conjugate programs are racing to establish best-in-class status. Overall, the update adds incremental pipeline optionality for Daiichi Sankyo and its partner but does not yet change the fundamental risk profile of the stock.

The study remains active in setup and has been recently updated, with further details available on the ClinicalTrials.gov portal under the listed identifier.

To learn more about DSKYF’s potential, visit the Daiichi Sankyo Company drug pipeline page.