CHICAGO — September 16, 2026
MAIA Biotechnology, Inc. announced that the first U.S. patient has been dosed in the Phase 2 THIO-101 clinical trial expansion evaluating ateganosine in third-line non-small cell lung cancer (NSCLC). The milestone follows FDA clearance of MAIA’s amended investigational new drug (IND) submission, which highlighted improvements in the company’s manufacturing capabilities and efficiencies. The U.S. expansion is supported by a $2.3 million National Institutes of Health (NIH) grant, specifically funding evaluation of ateganosine in patients receiving third-line treatment. MAIA has activated three U.S. clinical sites, expanding a study that is already enrolling patients across four continents. The company said the U.S. expansion strengthens the global development program for ateganosine and supports continued evaluation of the investigational therapy in patients with advanced disease who have progressed following standard checkpoint inhibitor treatment.
Ateganosine Combines Telomere Targeting With Immune Activation
Ateganosine (THIO, 6-thio-dG or 6-thio-2’-deoxyguanosine) is an investigational telomere-targeting therapy designed to combine direct cancer-cell effects with immune activation. The modified nucleotide induces telomerase-dependent modification of telomeric DNA, triggering DNA damage responses and selective cancer-cell death. Damaged telomeric fragments can accumulate in cytosolic micronuclei and activate innate cGAS/STING and adaptive T-cell immune responses. MAIA is evaluating ateganosine sequentially with the PD-(L)1 inhibitor cemiplimab (Libtayo), with the treatment strategy intended to prime an immune response before checkpoint inhibition. The company holds FDA Fast Track designation for ateganosine and is developing the candidate as a second- or later-line treatment for NSCLC patients with telomerase-positive cancer cells who have progressed after checkpoint inhibitor-containing standard treatment.
THIO-101 Evaluates Ateganosine in Heavily Pretreated NSCLC
The THIO-101 Phase 2 study is designed to evaluate ateganosine followed by PD-(L)1 inhibition in patients with advanced NSCLC who have previously received checkpoint inhibitor therapy. The multicenter, open-label, dose-finding study is evaluating the safety and tolerability of ateganosine as both an anticancer compound and an immune-priming agent, while overall response rate (ORR) serves as the primary clinical efficacy endpoint. The U.S. expansion specifically evaluates patients receiving third-line therapy who are resistant to previous checkpoint inhibitor and chemotherapy treatments. MAIA reported that prior THIO-101 Parts A and B generated overall survival beyond 24 months in eight patients treated with ateganosine sequenced with a checkpoint inhibitor. The company also reported an acceptable safety profile to date in a heavily pretreated population. These findings remain investigational and the ongoing Phase 2 expansion is intended to generate additional clinical evidence on response, durability and safety.
Advertisement
MAIA Advances Global Ateganosine Development Strategy
The addition of U.S. patients represents an important expansion of MAIA Biotechnology’s global ateganosine development program, while the NIH grant provides non-dilutive support for third-line NSCLC evaluation. With patients now enrolled across four continents, THIO-101 is becoming a broader international clinical program focused on a population with limited treatment options following resistance to established therapies. MAIA is also assessing whether data from the development program could potentially support an FDA accelerated approval pathway, although such a pathway is not guaranteed and would depend on regulatory requirements and clinical evidence. The company’s strategy centers on developing ateganosine as a potential first-in-class telomere-targeting therapy while combining its mechanism with checkpoint inhibition. With U.S. enrollment now underway, improved manufacturing capabilities cleared by the FDA, and NIH-backed clinical expansion, MAIA is advancing ateganosine toward a broader late-stage development strategy in difficult-to-treat NSCLC.
Source:MAIA Biotechnology, press release
