On June 25, 2026 MAIA Biotechnology, Inc. (NYSE American: MAIA) ("MAIA", the "Company"), a clinical-stage biopharmaceutical company focused on developing targeted immunotherapies for cancer, reported that it has completed international enrollment in Part C of its Phase 2 THIO-101 expansion trial evaluating its lead candidate, ateganosine, in advanced non-small cell lung cancer (NSCLC) patients receiving third line (3L) therapy. Ateganosine is an investigational dual-mechanism therapy targeting telomeres and immune activation in difficult-to-treat cancers.
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THIO-101 Part C patients, who are resistant to prior checkpoint inhibitor (CPI) therapy and chemotherapy, are randomized between MAIA’s proposed combination regimen of ateganosine followed by cemiplimab (Libtayo) and treatment with ateganosine alone for two cycles. International screening was conducted in Taiwan, Turkey, Poland, Hungary, Romania and Georgia, with 41 patients enrolled and receiving treatment. The Part C study is currently screening patients at multiple clinical sites in the United States.
"We greatly appreciate the dedication and contributions of the investigators supporting our THIO-101 trial," said Vlad Vitoc, Founder and Chief Executive Officer of MAIA Biotechnology. "With enrollment now complete at the international Part C clinical sites, we are closely monitoring patient outcomes as the data continues to mature, including key efficacy measures such as disease control rate and overall survival, which have remained central endpoints throughout the Phase 2 THIO-101 trial. Meanwhile, patient screening is ongoing at three activated clinical sites in the United States."
In Parts A and B of THIO-101, MAIA reported data showing median survival of 17.8 months. Overall survival (OS) beyond two years was observed for eight patients in Parts A and B of THIO-101; the patients did not receive subsequent lines of therapy. One patient in this cohort receiving 3L therapy has survived for over 33 months. Expected survival in this heavily pre-treated population is 5.8 months.1
The FDA has granted Fast Track designation for ateganosine in NSCLC treatment, potentially expediting the regulatory process to a potential Accelerated Approval and Priority Review.
About Ateganosine
Ateganosine (THIO, 6-thio-dG or 6-thio-2’-deoxyguanosine) is a first-in-class investigational telomere-targeting agent currently in clinical development to evaluate its activity in non-small cell lung cancer (NSCLC). Telomeres, along with the enzyme telomerase, play a fundamental role in the survival of cancer cells and their resistance to current therapies. The modified nucleotide 6-thio-2’-deoxyguanosine induces telomerase-dependent telomeric DNA modification, DNA damage responses, and selective cancer cell death. Ateganosine-damaged telomeric fragments accumulate in cytosolic micronuclei and activates both innate (cGAS/STING) and adaptive (T-cell) immune responses. The sequential treatment of ateganosine followed by PD-(L)1 inhibitors resulted in profound and persistent tumor regression in advanced, in vivo cancer models by induction of cancer type–specific immune memory. Ateganosine is presently developed as a second or later line of treatment for NSCLC for patients that have progressed beyond the standard-of-care regimen of existing checkpoint inhibitors.
About THIO-101 Phase 2 Clinical Trial
THIO-101 is a multicenter, open-label, dose finding Phase 2 clinical trial. It is the first trial designed to evaluate ateganosine’s anti-tumor activity when followed by PD-(L)1 inhibition. The trial is testing the hypothesis that low doses of ateganosine administered prior to cemiplimab (Libtayo) will enhance and prolong immune response in patients with advanced NSCLC who previously did not respond or developed resistance and progressed after first-line treatment regimen containing another checkpoint inhibitor. The trial design has two primary objectives: (1) to evaluate the safety and tolerability of ateganosine administered as an anticancer compound and a priming immune activator (2) to assess the clinical efficacy of ateganosine using Overall Response Rate (ORR) as the primary clinical endpoint. The expansion of the study will assess overall response rates (ORR) in advanced NSCLC patients receiving third line (3L) therapy who were resistant to previous checkpoint inhibitor treatments (CPI) and chemotherapy. Treatment with ateganosine followed by cemiplimab (Libtayo) has shown an acceptable safety profile to date in a heavily pre-treated population. For more information on this Phase II trial, please visit ClinicalTrials.gov using the identifier NCT05208944.
(Press release, MAIA Biotechnology, JUN 25, 2026, View Source [SID1234668959])