• NPRL2 Gene Therapy Induces Effective Anti-Tumor Activity in Non-Small Cell Lung Cancer Pembrolizumab Resistant Tumors in a Humanized Mouse Model
• Provides Preclinical Validation of the ONCOPREX® Nanoparticle Delivery System with a Second Tumor Suppressor Gene

AUSTIN, Texas, April 19, 2023 /PRNewswire/ -- 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, today announced that its research collaborators presented positive preclinical data for the NPRL2 gene (also known as the TUSC4 gene). The studies used the Company's non-viral ONCOPREX® Nanoparticle Delivery System in KRAS/STK11 mutant anti-PD1 resistant metastatic human non-small cell lung cancer (NSCLC) humanized mouse models and were presented at the 2023 American Association of Cancer Research (AACR) annual meeting, which took place from April 14-18, 2023 in Orlando, Florida.

"We are pleased to have these positive data that support the therapeutic potential of our non-viral delivery system, which is being used in our current REQORSA® clinical oncology programs, presented before some of the world's leading cancer researchers," said Rodney Varner, President and Chief Executive Officer at Genprex. "The use of the ONCOPREX® Nanoparticle Delivery System to deliver the NPRL2 tumor suppressor gene positions Genprex to expand our clinical pipeline with a new drug candidate."

"The preclinical data also provide further evidence that the ONCOPREX® Nanoparticle Delivery System has the ability to be successful using genes other than the TUSC2 gene that we are already using in clinical trials with REQORSA®," stated Varner. "These compelling outcomes give us further confidence in the potentially broad-based application of our non-viral delivery system, which may provide a multitude of potential pipeline opportunities in the future." 

Genprex's ONCOPREX® Nanoparticle Delivery System, is a novel non-viral approach utilizing lipid nanoparticles to deliver tumor suppressor genes that have been 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.

Featured Genprex-supported posters presented at AACR 2023 include:

Event: Americal Association of Cancer Research (AACR) Annual Meeting
Session Category: Immunology
Session Title: Combination Immunotherapies 2
Location: Section 22
Session Date and Time: Tuesday, April 18 from 1:30-5:00 p.m. ET
Title: "NPRL2 gene therapy induces effective antitumor immunity in KRAS/STK11 mutant anti-PD1 resistant metastatic human NSCLC in a humanizedmouse model"
Presenters: Jack A. Roth, MD, The University of Texas MD Anderson Cancer Center
Poster Board Number: 23
Abstract Presentation Number: 5120

The abstract entitled, "NPRL2 gene therapy induces effective antitumor immunity in KRAS/STK11 mutant anti-PD1 resistant metastatic human non-small cell lung cancer (NSCLC) in a humanized mouse model," is available on the AACR website. The presentation reported results from this study, which investigated the antitumor immune responses to NPRL2 gene therapy on anti-PD1 resistant KRAS/STK11 mutant NSCLC in a humanized mouse model. In the study, humanized mice were treated with NPRL2 gene therapy, immunotherapy pembrolizumab (Keytruda®), or the combination. A dramatic antitumor effect was mediated by NPRL2 treatment, whereas pembrolizumab was ineffective. A significant antitumor effect was also found in non-humanized NSG mice, although the antitumor effect was greater in humanized mice, suggesting that the immune response played a role in inducing antitumor activity.

The study data suggest that NPRL2 gene therapy induces antitumor activity on KRAS/STK11 mutant anti-PD1 resistant tumors through DC mediated antigen presentation and cytotoxic immune cell activation.

A KRAS mutation occurs in approximately 25% of patients with NSCLC, and one study found that KRAS/STK11 combination mutations were found in approximately 6.5% of NSCLC patients.

"These data are encouraging because they not only validate Genprex's non-viral oncology platform to deliver a variety of tumor suppressor genes, but they also provide further evidence of the important role that tumor suppressor genes play in cancer, particularly NSCLC," said Mark Berger, MD, Chief Medical Officer at Genprex. "KRAS is the most frequent oncogene mutated in NSCLC, and KRAS mutations are often associated with resistance to drug therapyⁱ. Targeting KRAS/STK11 mutant NSCLC with the NPRL2 gene, and potentially with anti-PD1 as well, may provide therapeutic potential for this group of lung cancer patients."

Genprex currently has three clinical trials evaluating the Company's lead drug candidate, REQORSA® Immunogene Therapy (quaratusugene ozeplasmid) in lung cancer. The Acclaim-1 clinical trial, which received FDA Fast Track Designation, is an open-label, multi-center Phase 1/2 clinical trial evaluating REQORSA in combination with Tagrisso® (osimertinib) in patients with late-stage NSCLC with activating epidermal growth factor receptor ("EGFR") mutations whose disease progressed after treatment with Tagrisso. The Acclaim-2 clinical trial, which received FDA Fast Track Designation, is an open-label, multi-center Phase 1/2 clinical trial evaluating REQORSA in combination with Keytruda® (pembrolizumab) in patients with late-stage NSCLC whose disease progressed after treatment with Keytruda. The Acclaim-3 clinical trial, expected to open for enrollment by the end of the third quarter of 2023, is an open-label, multi-center Phase 1/2 clinical trial evaluating REQORSA in combination with Tecentriq® (atezolizumab) in patients with extensive-stage small-cell lung cancer (SCLC) who did not develop tumor progression after receiving Tecentriq and chemotherapy as an initial treatment.

The AACR abstract has been made available on Genprex's website here.

About Genprex, Inc.

Genprex, Inc. is a clinical-stage gene therapy company focused on developing life-changing therapies for patients with cancer and diabetes. Genprex's technologies are designed to administer disease-fighting genes to provide new therapies for large patient populations with cancer and diabetes who currently have limited treatment options. Genprex works with world-class institutions and collaborators to develop drug candidates to further its pipeline of gene therapies in order to provide novel treatment approaches. Genprex's oncology program utilizes its proprietary, non-viral ONCOPREX® Nanoparticle Delivery System which encapsulates the gene-expressing plasmids using lipid nanoparticles. The resultant product is administered intravenously, where it is then taken up by tumor cells that express tumor suppressor proteins that are deficient in the tumor. The Company's lead product candidate, REQORSA® (quaratusugene ozeplasmid), is being evaluated in three clinical trials as a treatment for non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). Both NSCLC clinical programs received a Fast Track Designation from the Food and Drug Administration. Genprex's diabetes gene therapy approach is comprised of a novel infusion process that uses an adeno-associated virus (AAV) vector to deliver Pdx1 and MafA genes directly to the pancreas. In models of Type 1 diabetes, GPX-002 transforms alpha cells in the pancreas into functional beta-like cells, which can produce insulin but are distinct enough from beta cells to evade the body's immune system. In a similar approach, GPX-003 for Type 2 diabetes, where autoimmunity is not at play, is believed to rejuvenate and replenish exhausted beta cells.

For more information, please visit the Company's web site at www.genprex.com or follow Genprex on Twitter, Facebook and LinkedIn.

Cautionary Language Concerning Forward-Looking Statements

Statements contained in this press release regarding matters that are not historical facts are "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. These forward-looking statements are made on the basis of the current beliefs, expectations and assumptions of management, are not guarantees of performance and are subject to significant risks and uncertainty. These forward-looking statements should, therefore, be considered in light of various important factors, including those set forth in Genprex's reports that it files from time to time with the Securities and Exchange Commission and which you should review, including those statements under "Item 1A – Risk Factors" in Genprex's Annual Report on Form 10-K for the year ended December 31, 2022.

Because forward-looking statements are subject to risks and uncertainties, actual results may differ materially from those expressed or implied by such forward-looking statements. Such statements include, but are not limited to, statements regarding: Genprex's ability to advance the clinical development, manufacturing and commercialization of its product candidates in accordance with projected timelines; the timing and success of Genprex's clinical trials and regulatory approvals; the effect of Genprex's product candidates, alone and in combination with other therapies, on cancer and diabetes; Genprex's future growth and financial status, including Genprex's ability to continue to obtain capital to meet its long-term liquidity needs on acceptable terms, or at all; Genprex's commercial and strategic partnerships, including those with its third party vendors, suppliers and manufacturers and their ability to successfully perform and scale up the manufacture of its product candidates; and Genprex's intellectual property and licenses.

These forward-looking statements should not be relied upon as predictions of future events and Genprex cannot assure you that the events or circumstances discussed or reflected in these statements will be achieved or will occur. If such forward-looking statements prove to be inaccurate, the inaccuracy may be material. You should not regard these statements as a representation or warranty by Genprex or any other person that Genprex will achieve its objectives and plans in any specified timeframe, or at all. You are cautioned not to place undue reliance on these forward-looking statements, which speak only as of the date of this press release. Genprex disclaims any obligation to publicly update or release any revisions to these forward-looking statements, whether as a result of new information, future events or otherwise, after the date of this press release or to reflect the occurrence of unanticipated events, except as required by law.

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ⁱ _{FDA Approves First Targeted Therapy for Lung Cancer Mutation Previously Considered Resistant to Drug Therapy | FDA}