On April 17, 2026 Adagene Inc. ("Adagene") (Nasdaq: ADAG), a company transforming the discovery and development of novel antibody-based therapies, reported new data from two ongoing Phase 1b/2 studies of muzastotug in triple combination regimens at the American Association of Cancer Research (AACR) (Free AACR Whitepaper) annual meeting 2026, held April 17-22 in San Diego. Results support muzastotug’s mechanistic advantages over traditional anti-CTLA-4 therapies, and its continued development as a potential backbone therapy in combination regimens for difficult-to-treat cancers. FDA has previously designated muzastotug in combination with Merck’s (known as MSD outside of the United States and Canada) anti-PD-1 therapy, KEYTRUDA (pembrolizumab), as a Fast Track product for adult patients with microsatellite stable metastatic colorectal cancer (MSS mCRC) without current or active liver metastases.
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"At AACR (Free AACR Whitepaper), Adagene shared new data from two triplet regimens supporting muzastotug’s potential as a combination backbone for multiple tumor types, said Peter Luo, Ph.D., CEO and President of R&D at Adagene. In HCC, adding muzastotug to the atezolizumab plus bevacizumab combo resulted in higher efficacy, with a safety profile consistent with historical studies of the doublet alone. In MSS CRC, adding muzastotug to pembrolizumab plus fruquintinib showed dose-dependent response rates, with no DLTs or Grade 4 or 5 treatment related adverse events. As muzastotug continues to generate more data in additional settings, we are increasingly convinced that its intentionally designed wider therapeutic index has potential to improve the efficacy of current immunotherapies without worsening the toxicity for patients with difficult to treat solid tumors."
Final copies of the two posters from AACR (Free AACR Whitepaper) can be found on the Pipeline Publications section of the company’s website.
AACR Poster Presentations
Abstract CT054
The MORPHEUS-Liver study (NCT04524871) is a Phase 1b/2 open-label randomized umbrella study designed to evaluate immunotherapy-based combinations as first line therapy in patients with locally advanced or metastatic hepatocellular carcinoma (HCC). As of July 11, 2025, six patients had been randomized to the triple combination of muzastotug (6 mg/kg Q6W), atezolizumab and bevacizumab and 40 patients had received atezolizumab and bevacizumab in the active control arm. Interim results from patients in the muzastotug arm (18.8 months median duration of follow-up) demonstrated a 66.7% overall response rate (ORR; 4/6) using HCC-specified modified RECIST v1.1 criteria1. ORR was 50.0% (3/6) using RECIST v1.1 criteria. The median progression free survival (mPFS) was 8.2 months (same for both RECIST criteria) and the median overall survival (mOS) was not yet reached at the data cut but was greater than 22 months.
These results compared favorably to the 40 patients in the active control arm (17.2 months median duration of follow-up) that demonstrated an ORR of 32.5% (13/40) using HCC-specified modified RECIST v1.1 criteria, mPFS of 5.5 months, and mOS of 17.5 months. Using RECIST v1.1 criteria, the ORR was 17.5% (7/40) and the mPFS was 4.3 months. The mOS in the doublet control arm was largely overlapping with that reported in the IMbrave150 Phase 3 study2,3 (19.2 months), which served as the basis for approval of atezolizumab (Tecentriq) for HCC in 20204.
The triplet regimen of muzastotug, atezolizumab and bevacizumab was well-tolerated with safety data comparable to the doublet active control arm of atezolizumab and bevacizumab. Grade 3 or greater TRAEs were 50% (3/6) in the muzastotug arm and 45% (18/40) in the active control arm, which supports the potential for continuous dosing with muzastotug. Muzastotug was safely administered continuously at 6 mg/kg Q6W in a triplet setting, which is twice the dose of ipilimumab in the currently approved HCC doublet regimen, (capped at 3 mg/kg Q3W for only 4 cycles)5. In addition, encouraging durability was observed with responses maintained beyond 84 weeks in some patients. Ongoing muzastotug plus atezolizumab treatment after bevacizumab discontinuation suggests potential flexibility to modify individual agents during safety-related interruptions while preserving durable clinical benefit.
Abstract CT083
A Phase 1b/2 single arm study (NCT05405595) is evaluating the triple combination of muzastotug, pembrolizumab and fruquintinib in patients with advanced and metastatic microsatellite stable (MSS) colorectal cancer (CRC). As of February 21, 2026, nine patients have been treated with the triple combination — four (4) patients at a dose of 10 mg/kg every 6 weeks (Q6W) of muzastotug and five (5) patients at a dose of 15 mg/kg Q6W of muzastotug. All patients were without liver metastases (NLM). Interim results demonstrated a 25% ORR (1/4) among patients in the 10 mg/kg arm (6.7 months median follow-up), and a 40% ORR (2/5) among patients in the 15 mg/kg arm (5.9 months median follow-up).
The triplet regimen was well-tolerated with no new safety signals relative to known CTLA-4, PD-1, and fruquintinib monotherapy and combination safety data. There were no dose-limiting toxicities, 25 – 60% Grade 3 TRAEs, and no Grade 4 or Grade 5 TRAEs. Given that fruquintinib is known to be active in MSS CRC patients with liver metastases, the triple combination may have therapeutic benefit beyond the NLM population being evaluated in this study.
(Press release, Adagene, APR 17, 2026, View Source [SID1234664466])