On May 26, 2026 Genprex, Inc. ("Genprex" or the "Company") (NASDAQ: GNPX), a clinical-stage gene therapy company focused on developing life-changing therapies for patients with cancer and diabetes, reported that its research collaborators’ abstract was published at the 2026 American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) Annual Meeting. The abstract details positive clinical data from studies of predictive biomarkers in patients receiving its lead drug candidate, Reqorsa Gene Therapy (quaratusugene ozeplasmid), for the treatment of lung cancer.

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"This clinical validation, derived from patients in our Acclaim clinical trials, substantiates earlier preclinical evidence revealing that Non-Small Cell Lung Cancer (NSCLC) patients receiving REQORSA who exhibit high Trop-2 levels and low PTEN levels experience prolonged Progression Free Survival (PFS), underscoring the critical role these biomarkers play in predicting treatment efficacy and advancing our understanding of this novel gene therapy," said Ryan Confer, President and Chief Executive Officer at Genprex. "These findings represent a substantial leap forward for personalized medicine in lung cancer, allowing for a targeted approach to potentially improve treatment outcomes and optimize resource allocation within the therapeutic landscape."

The featured Genprex-supported abstract at ASCO (Free ASCO Whitepaper) 2026:

Title: "Predictive biomarkers for PFS in patients receiving quaratusugene ozeplasmid"

Abstract Number: e15184

Quaratusugene ozeplasmid is a gene therapy that delivers a plasmid coding for the TUSC2 tumor suppressor gene to lung cancer cells, as >80% of lung cancers have been shown to have decreased or absent TUSC2 protein. TUSC2 protein levels have not correlated with PFS, presumably because of the complexities of TUSC2 protein regulation. Preclinical studies have identified higher levels of Trop-2 protein in organoids and lower levels of PTEN protein in lung cancer cell lines as correlating with response (AACR 2026). Tumor tissue from patients in clinical trials with quaratusugene ozeplasmid were evaluated for Trop-2 and PTEN protein expression.

Monoclonal antibodies against Trop-2 (BSB148 from BioSB) and PTEN (138G6 from Cell Signaling Technology) were used for immunohistochemistry in paraffin sections from archival tumor samples in patients enrolled in three clinical trials with quaratusugene ozeplasmid and results expressed as H-scores. H-scores were calculated by evaluating diaminobenzidine staining intensity using the formula [1 × (% cells 1+) + 2 × (% cells 2+) + 3 × (% cells 3+)].

Data on Trop-2 and PTEN protein expression and data on PFS were available from 18 patients enrolled in clinical trials with quaratusugene ozeplasmid.

Six patients with NSCLC were enrolled in the Acclaim-1 trial in combination with osimertinib.
One patient was enrolled in the Acclaim-2 trial in combination with pembrolizumab.
Eleven patients with small cell lung cancer (SCLC) were enrolled in the Acclaim-3 trial in combination with atezolizumab.
In patients with NSCLC, Trop-2 H-scores above 100 correlated with prolonged PFS (p=0.05), and PTEN H-scores below 100 correlated with prolonged PFS (p=0.03).
In patients with SCLC, Trop-2 H-scores were universally low, and thus non-evaluable. PTEN H-scores in patients with SCLC did not correlate with prolonged PFS (p=0.53).
Following up on preclinical cell line and organoid models indicating that Trop-2 and PTEN protein expression correlated with response, levels of Trop-2 and PTEN protein were evaluated in patients treated with quaratusugene ozeplasmid. In conclusion, both Trop-2 H-scores above 100 and PTEN H-scores below 100 correlated with longer PFS in patients with NSCLC, but not in patients with SCLC.

Beyond the ASCO (Free ASCO Whitepaper) 2026 Abstract:

Following the clinical studies outlined above, Genprex completed additional analysis to evaluate the relationship between NSCLCs with high intensity staining (3+) and PFS. NSCLCs with 3+ Trop-2 staining had a strong relationship with PFS that was just outside the bounds for significance (p=0.053) and those with 3+ PTEN staining exhibited a trend for a negative relationship with PFS that was not statistically significant (p=0.309). These results are consistent with the H-score analysis regarding a strong positive relationship between Trop-2 expression and PFS. High (3+) Trop-2 expression will be investigated further as a potential biomarker for REQORSA.

"We look forward to additional studies using intensity staining to understand the correlation between Trop-2 expression and PFS, offering more concrete data for optimized patient selection," said Mark S. Berger, Chief Medical Officer at Genprex.

About Acclaim-1

The Acclaim-1 clinical trial is an open-label, multi-center Phase 1/2 clinical trial evaluating REQORSA in combination with AstraZeneca’s Tagrisso (osimertinib) in patients with late-stage NSCLC with activating epidermal growth factor receptor (EGFR) mutations whose disease progressed after treatment with Tagrisso or or Tagrisso-containing regimens. Acclaim-1 received Fast Track Designation by the U.S. Food and Drug Administration (FDA) for use of REQORSA in combination with TKI Tagrisso for the treatment of NSCLC patients with EGFR mutations whose tumors progressed after treatment with Tagrisso.

About Acclaim-3

The Acclaim-3 clinical trial is an open-label, multi-center Phase 1/2 clinical trial evaluating REQORSA in combination with Genentech, Inc.’s Tecentriq (atezolizumab) as maintenance therapy in patients with extensive stage small cell lung cancer (ES-SCLC) who did not develop tumor progression after receiving Tecentriq and chemotherapy as initial standard treatment. Acclaim-3 received Fast Track Designation by the FDA for the Acclaim-3 treatment combination of REQORSA and Tecentriq as maintenance therapy in patients with ES-SCLC who did not develop tumor progression after receiving Tecentriq and chemotherapy as initial standard treatment. The FDA also granted Orphan Drug Designation to REQORSA for the treatment of SCLC.

(Press release, Genprex, MAY 26, 2026, View Source [SID1234666051])