San Diego, USA & Suzhou, China, April 2, 2026
Strong Clinical Efficacy in MSS Colorectal Cancer
In a major advancement for immuno-oncology research, Adagene Inc. has announced updated results from its Phase 1b/2 clinical trial evaluating muzastotug (ADG126) in combination with KEYTRUDA® (pembrolizumab) in patients with microsatellite stable colorectal cancer (MSS CRC)—a subtype known for its poor response to conventional immunotherapies. The latest data reveal a dose-dependent improvement in overall response rate (ORR), with 31% ORR in the 20 mg/kg cohort compared to 13% in the 10 mg/kg group, highlighting a clear efficacy advantage at higher dosing levels.
Importantly, the median duration of response (mDOR) was not reached in the higher-dose cohort, with responses continuing beyond nine months, indicating durable anti-tumor activity in heavily pretreated patients. Additionally, progression-free survival (PFS) improved to 6.7 months at 20 mg/kg, compared to 4.8 months at lower doses, reinforcing the therapy’s potential to deliver clinically meaningful outcomes in this difficult-to-treat population.
Survival Benefits and Safety Profile Highlight Differentiation
Beyond response rates, the study demonstrated encouraging survival outcomes, a critical benchmark in oncology trials. Patients in the 10 mg/kg cohort achieved a median overall survival (OS) of 19.8 months, with 48% survival at two years, reflecting the characteristic long-tail survival benefit of CTLA-4–based immunotherapies. Meanwhile, the 20 mg/kg cohort showed a one-year survival rate of 80.8%, suggesting even greater potential benefit at optimized dosing. Notably, the therapy maintained a favorable safety profile, with no dose-limiting toxicities and no Grade 4 or 5 treatment-related adverse events reported across all cohorts.
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The overall discontinuation rate was only 4%, underscoring strong tolerability. While Grade 3 adverse events were higher in the 20 mg/kg group (38%), they were described as manageable and transient, supporting the feasibility of dose escalation. Common side effects included pruritus, fatigue, hypothyroidism, and diarrhea, with relatively low incidence of severe gastrointestinal toxicity. These findings position muzastotug as a potentially safer and more effective alternative to traditional anti-CTLA-4 therapies, which are often limited by toxicity concerns.
Phase 2 Expansion and Regulatory Momentum
Building on these promising results, Adagene is advancing into a randomized Phase 2 trial, designed in collaboration with the U.S. FDA, to further evaluate optimal dosing strategies and confirm efficacy outcomes. The study will enroll up to 60 late-line MSS CRC patients without liver metastases, comparing two dosing regimens of muzastotug in combination with pembrolizumab. The trial’s primary endpoint is overall response rate, with secondary endpoints including duration of response, progression-free survival, and overall survival.
Initial results are anticipated in the first half of 2027, with the potential for a registration-enabling trial to follow. Notably, the combination therapy has already received FDA Fast Track designation, reflecting its potential to address a significant unmet medical need in colorectal cancer treatment. This regulatory support may accelerate development timelines and facilitate earlier patient access if clinical benefits are confirmed.
Advancing SAFEbody Technology in Oncology
The success of this study also validates Adagene’s proprietary SAFEbody® platform, a next-generation antibody engineering approach designed to improve the therapeutic window of immunotherapies. By enabling tumor-specific activation and reducing off-target toxicity, SAFEbody technology addresses one of the most critical challenges in cancer treatment—balancing efficacy with safety. MSS CRC has long been considered an “immune cold tumor”, resistant to checkpoint inhibitors due to limited immune infiltration.
However, the combination of CTLA-4 inhibition with PD-1 blockade, enhanced by SAFEbody precision, appears to reactivate immune responses within the tumor microenvironment. As the oncology field increasingly shifts toward combination and precision-based therapies, Adagene’s approach could play a pivotal role in expanding the reach of immunotherapy to previously unresponsive cancers. These findings mark a significant milestone in colorectal cancer research and highlight the potential for innovative biologics to redefine treatment paradigms in oncology.
Source: Adagene press release
