FDA Grants Fast Track Designation to Ateganosine for NSCLC

The FDA has granted fast track designation to ateganosine (6-thio-dG or 6-thio-2’-deoxyguanosine; THIO) as a potential therapeutic option for patients with non–small cell lung cancer (NSCLC).1

Ateganosine is currently being evaluated in the phase 2 THIO-101 trial (NCT05208944), which is examining the agent given in combination with cemiplimab (Libtayo) in patients with advanced NSCLC who previously received first-line treatment with an immune checkpoint inhibitor–containing regimen.2

“FDA’s fast track designation recognizes ateganosine’s potential as a new therapeutic paradigm in cancer treatment science. Ateganosine is the first and only anticancer treatment of its kind that we are aware of in clinical development,” Vlad Vitoc, MD, chairman and chief executive officer of MAIA Biotechnology, stated in a news release.1 “If we are successful in the fast Track regulatory pathway, ateganosine could qualify for accelerated FDA approval and robust exclusivity in NSCLC, with a potential FDA decision as early as next year.”

THIO-101 Overview

The multicenter, open-label, dose-finding phase 2 study is enrolling patients at least 18 years of age with histologically or cytologically confirmed stage III or IV NSCLC who experienced disease progression or relapse following treatment in the advanced setting.2 For patients with stage IV disease, progression or relapse after first-line treatment is required in parts A and B of the study; in parts C and D, patients with stage IV disease are allowed to enroll if they experienced disease progression or relapse, or discontinued due to toxicity, after 2 lines of treatment in the advanced setting. Patients with stage III disease need to be ineligible for local curative-intent therapy, and they need to have relapse or progression after consolidation therapy with durvalumab (Imfinzi).

Other key inclusion criteria comprise secondary resistance to prior immune checkpoint inhibitor therapy, at least 1 measurable target lesion per RECIST 1.1 criteria, an ECOG performance status of 0 or 1, and adequate organ function. Notably, no prior targeted therapy for driver mutations is permitted.

Part A of the study is a safety lead-in being conducted with a modified 3+3 design, evaluating ateganosine at 360 mg per 3-week cycle, with the agent dosed at 120 mg on days 1 to 3. In part B, patients are being randomly assigned to receive ateganosine at doses of 60 mg, 180 mg, or 360 mg per cycle in combination with cemiplimab.

In part C, patients will receive ateganosine at 60 mg per day on days 1 to 3 of each cycle with or without cemiplimab given at 350 mg on day 5. Part D is examining a ateganosine dose of 180 mg per cycle with cemiplimab for patients receiving third-line therapy.

The study’s primary end points are the incidence of dose-limiting toxicities in part A, overall response rate, disease control rate, and safety. Secondary end points comprise duration of response, progression-free survival, overall survival, and additional safety findings.

“This is an important milestone for MAIA’s clinical development program. Ateganosine has demonstrated robust preclinical efficacy and superior clinical median overall survival compared to other FDA-approved treatments for [patients with] NSCLC with prior disease progression on platinum-based chemotherapy and [an] anti-PD-[L]1 antibody,” K. Robinson Lewis, vice president and head of Regulatory and Quality at MAIA Biotechnology, added in a news release.1 “Additionally, advanced NSCLC is a devastating disease that clearly meets the criteria for a serious condition with unmet medical need. Both are key criteria for the fast track designation. We intend to utilize the incentives of the fast track program to expedite the development and review of ateganosine and bring patient access sooner.”

References

1. MAIA Biotechnology receives FDA’s fast track designation for ateganosine as a treatment for non-small cell lung cancer. News release. MAIA Biotechnology. July 28, 2025. Accessed July 30, 2025. https://ir.maiabiotech.com/news-events/press-releases/detail/146/maia-biotechnology-receives-fdas-fast-track-designation
2. THIO sequenced with cemiplimab in advanced NSCLC. ClinicalTrials.gov. Updated May 31, 2025. Accessed July 30, 2025. https://clinicaltrials.gov/study/NCT05208944