On April 2, 2024 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 have published positive preclinical data for the NPRL2 tumor suppressor gene, utilizing the Company’s non-viral Oncoprex Delivery System, in KRAS/STK11 mutant anti-PD1 resistant non-small cell lung cancer (NSCLC) in a humanized mouse model (Press release, Genprex, APR 2, 2024, View Source [SID1234641694]).

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NPRL2 is a tumor suppressor gene whose expression is reduced in many cancers including lung, renal, colorectal, glioma, gastric, and hepatocellular carcinoma, and it has been closely correlated with poor clinical outcomes.

Genprex’s Oncoprex Delivery System is a novel non-viral approach that utilizes lipid-based nanoparticles in a lipoplex form to deliver tumor suppressor genes deleted during the course of cancer development. The platform allows for the intravenous delivery of various tumor suppressor genes, and potentially other genes, to achieve a therapeutic affect without the risk of toxicity often associated with viral delivery systems. Genprex believes this system allows for delivery of a number of cancer-fighting genes, alone or in combination with other cancer therapies, to combat multiple types of cancer.

The manuscript, titled, "NPRL2 gene therapy induces effective anti-tumor immunity in KRAS/STK11 mutant anti-PD1 resistant metastatic non-small cell lung cancer (NSCLC) in a humanized mouse model," was published on the bioRxiv biology preprint server.

"These positive preclinical data are very encouraging and support NPRL2 gene therapy as a potential treatment for a sub-group of NSCLC in which patients traditionally are resistant to existing therapies," said Rodney Varner, President, Chairman and Chief Executive Officer at Genprex. "We believe this data could support the potential for a new drug candidate in our pipeline, and it also provides further evidence that the Oncoprex Delivery System has the ability to be successful using genes other than the TUSC2 gene we are already using in clinical trials with Reqorsa."

The studies evaluated the intravenous injection of NPRL2 gene-loaded cationic lipoplexes (DOTAP-NPRL2) with or without anti-PD1 drugs (pembrolizumab). The studies used a KRAS/STK11 mutant anti-PD1 insensitive cell line, as well as syngeneic mouse LLC2 tumors, which are also anti-PD1 resistant. In both of these mouse models, NPRL2 showed a significantly strong anti-tumor effect whereas anti-PD1 (pembrolizumab) was not effective. The anti-tumor effect was greater in humanized mice than non-humanized mice, suggesting that an immune response contributed to anti-tumor activity.

Additionally, a dramatic anti-tumor effect was mediated by NPRL2 treatment with or without a pembrolizumab combination. Bioluminescence imaging on mice showed that 7 out of 10 mice contained an extremely low amount of tumor burden in the NPRL2 treatment group, which was significantly different than in the control or pembrolizumab group.

Unlike previous experiments with Reqorsa Immunogene Therapy (quartusugene ozeplasmid), the Company’s lead drug candidate using the TUSC2 tumor suppressor gene, the anti-tumor efficacy of DOTAP-NPRL2 did not involve Natural Killer (NK) cells. The studies also found that tumors with stable NPRL2 expression exhibited significantly slower growth compared to controls. In conclusion, researchers reported that NPRL2 gene therapy induces anti-tumor activity through dendritic cell-mediated antigen presentation and cytotoxic immune cell activation.