• Outstanding measure of efficacy relative to high-risk cancers with limited treatment options

CHICAGO, Oct. 23, 2025 (GLOBE NEWSWIRE) -- MAIA Biotechnology, Inc. (NYSE American: MAIA) (“MAIA”, the “Company”), a clinical-stage biopharmaceutical company focused on developing targeted immunotherapies for cancer, today announced highlights from a recent presentation at the European Society for Medical Oncology (ESMO) Congress 2025 held in Berlin, Germany. Starting October 19, 2025, MAIA showcased two e-posters at ESMO detailing its ongoing Phase 2 and Phase 3 clinical trials of ateganosine in non-small cell lung cancer (NSCLC).

“The posters showcased at ESMO 2025 featured exceptional extended survival in third-line NSCLC patients. In addition, as of September 17, 2025, a patient that began therapy in March 2023 has shown survival of 30 months, or 912 days, an outstanding measure relative to many of the high-risk cancers,” said MAIA CEO Vlad Vitoc, M.D. “Very few options exist for patients who are refractory or resistant to immune checkpoint inhibitors (ICI). We believe that a survival of over two years is a clear signal of ateganosine’s role in effectively targeting and eliminating NSCLC tumor cells.”

The THIO-101 patient with 30-month survival received therapy every three weeks, and concluded treatment upon reaching the maximum treatment duration of 2 years based on protocol requirements.

MAIA’s newest posters featured at ESMO 205 are now available on MAIA’s website at maiabiotech.com/publications .

  • Presentation 1: A Phase 2 Study of Ateganosine (THIO; 6-thio-2'-deoxyguanosine) in Combination with Immune Checkpoint Inhibitor (ICI) in Patients with Advanced Non-Small Cell Lung Cancer (NSCLC) Resistant to Prior ICI and Chemotherapy: THIO-101 Trial in Progress

  • Presentation 2: A Phase 3 Study of Ateganosine (THIO) Sequenced with Immune Checkpoint Inhibitor (ICI) versus Standard of Care Chemotherapy in ICI-Resistant Advanced NSCLC: THIO-104 Trial in Progress

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.

About MAIA Biotechnology, Inc.
MAIA is a targeted therapy, immuno-oncology company focused on the development and commercialization of potential first-in-class drugs with novel mechanisms of action that are intended to meaningfully improve and extend the lives of people with cancer. Our lead program is ateganosine (THIO), a potential first-in-class cancer telomere targeting agent in clinical development for the treatment of NSCLC patients with telomerase-positive cancer cells. For more information, please visit www.maiabiotech.com .

Forward Looking Statements
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