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Acclaim-1 Phase 1 study had no Dose Limiting Toxicity, and results establish Phase 2 Recommended Dose as well as provide data showing efficacy of REQORSA® in combination with Tagrisso®

Preclinical results show that REQORSA® in combination with a checkpoint inhibitor has anti-tumor activity in a humanized mouse model of small cell lung cancer (SCLC)

AUSTIN, Texas, Oct. 4, 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 research collaborators will present positive clinical and preclinical data from studies of its lead product candidate, REQORSA® (quaratusugene ozeplasmid) used for the treatment of lung cancers, at the 2023 AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics taking place from October 11-15, 2023 at the Hynes Convention Center in Boston. REQORSA is a non-viral gene therapy that leads to expression of the TUSC2 tumor suppressor gene in cancers.

"The encouraging Phase 1 results in the Acclaim-1 trial document REQORSA's favorable safety profile thus far and show early efficacy in patients with non-small cell lung cancer (NSCLC) whose disease has progressed on Tagrisso. Importantly, there were no Dose Limiting Toxicities. Based on these results, the Safety Review Committee has recommended that we move forward with the Phase 2 expansion portion of the study, which moves us one step closer to our goal of bringing this potentially life-saving therapy to patients," said Rodney Varner, Chairman, President and Chief Executive Officer at Genprex. "In addition, the preclinical data presented by our research collaborators is very encouraging, as we know that despite the broader success of immunotherapies, such as checkpoint inhibitors, they have limited efficacy in the treatment of small cell lung cancer. We look forward to evaluating REQORSA in combination with a checkpoint inhibitor to treat SCLC in our upcoming Acclaim-3 clinical trial, where we have both FDA Fast Track and Orphan Drug Designations for this patient population."

Details of the presentations are outlined below:

Dr. Spira's presentation will focus on the results of the Phase 1 dose escalation portion of the Acclaim-1 clinical trial of REQORSA in combination with Tagrisso® (osimertinib) to treat late-stage NSCLC. Results showed REQORSA was generally well tolerated with no Dose Limiting Toxicities. Of the 12 patients treated with escalating doses of REQORSA and standard doses of Tagrisso, all of whom had progressed on Tagrisso containing regimens, two patients experienced prolonged time to progression, including one with continuing partial response. While REQORSA administration was associated with delayed infusion-related reactions of muscle aches, fever and chills in some patients, this was managed with prophylactic steroids, acetaminophen and diphenhydramine, and symptoms decreased with repeat cycles.

The study's Safety Review Committee met and determined that the recommended Phase 2 dose for REQORSA in combination with Tagrisso in patients with NSCLC progressing after Tagrisso treatment will be 0.12 mg/kg. This was the highest dose level delivered in the Phase 1 portion and is twice the highest dose level delivered in Genprex's prior clinical trial combining REQORSA with Tarceva® (erlotinib) for the treatment of late-stage NSCLC. The SRC also recommended the trial advance to the Phase 2 expansion portion of the study.

The combination of REQORSA and Tagrisso received U.S. Food and Drug Administration's (FDA) Fast Track Designation for treatment of the Acclaim-1 patient population.

The study evaluated REQORSA, referred to as TUSC2 gene therapy in the abstract, in combination with the immune checkpoint inhibitor Tecentriq® (atezolizumab) for the treatment of chemotherapy resistant SCLC tumors in humanized mice. The use of humanized mice allowed an evaluation of the human immune cell subtypes that infiltrated the tumor.

Study authors concluded that TUSC2 expression is reduced in almost all SCLC tumors and absent in 41%. The researchers investigated the antitumor response to TUSC2 gene therapy in combination with Tecentriq. The data show that TUSC2 gene therapy in combination with Tecentriq induces strong antitumor activity in a chemo-resistant SCLC through cytotoxic CD8 T- and NK-cell activation, as the study found that CD8 T and NK-cell infiltration in the tumor was increased by REQORSA.

The combination of REQORSA and the checkpoint inhibitor Tecentriq received FDA Fast Track and Orphan Drug Designations for treatment of the Acclaim-3 patient population.

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 the type of toxicity often associated with viral delivery systems.

The aforementioned 2023 AACR-NCI-EORTC posters will be available on Genprex's website here following the completion of their live presentations.

About the Acclaim Clinical Trials in Lung Cancers
Genprex currently has three clinical trials evaluating the Company's lead drug candidate, REQORSA® (quaratusugene ozeplasmid) in lung cancer. The Acclaim-1 clinical trial, whose patient population 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 mutations whose disease progressed after treatment with Tagrisso. The Acclaim-2 clinical trial, whose patient population 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 upcoming Acclaim-3 clinical trial is an open-label, multi-center Phase 1/2 clinical trial evaluating REQORSA in combination with Tecentriq® (atezolizumab) as maintenance therapy in patients with extensive-stage SCLC who did not develop tumor progression after receiving Tecentriq and chemotherapy as an initial treatment. The FDA granted both Fast Track and Orphan Drug Designation for REQORSA in the Acclaim-3 patient population.

About REQORSA® Immunogene Therapy
REQORSA® (quaratusugene ozeplasmid) for NSCLC and SCLC consists of the TUSC2 gene expressing plasmid encapsulated in non-viral nanoparticles made from lipid molecules (Genprex's ONCOPREX® Nanoparticle Delivery System) with a positive electrical charge. REQORSA is injected intravenously and specifically targets cancer cells, which generally have a negative electrical charge. REQORSA is designed to deliver the functioning TUSC2 gene to cancer cells while minimizing their uptake by normal tissue. REQORSA has a multimodal mechanism of action whereby it interrupts cell signaling pathways that cause replication and proliferation of cancer cells, re-establishes pathways for programmed cell death, or apoptosis, in cancer cells, and modulates the immune response against cancer cells.

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 systemic, non-viral ONCOPREX® Nanoparticle Delivery System which encapsulates the gene-expressing plasmids using lipid nanoparticles. The resultant product is administered intravenously, where it is taken up by tumor cells that then express tumor suppressor proteins that were 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). Each of Genprex's three lung cancer clinical programs has received a Fast Track Designation from the FDA for the treatment of that patient population, and Genprex's SCLC program has received an FDA Orphan Drug Designation. 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 may be 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.

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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 and specifications; 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 as a going concern and 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.

Genprex, Inc.
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SOURCE Genprex, Inc.