Genprex Publishes Positive Clinical Data from Phase 1 Portion of Acclaim-1 Clinical Trial Evaluating REQORSA® Immunogene Therapy in Non-Small Cell Lung Cancer at the 2023 ASCO Annual Meeting

Results Show Combination of REQORSA® and Tagrisso® was Well Tolerated at All Three Dose Levels of Phase 1 Trial with Encouraging Evidence of Efficacy Observed

AUSTIN, Texas, May 25, 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 positive data from the Phase 1 portion of its Acclaim-1 clinical trial evaluating REQORSA® Immunogene Therapy in combination with Tagrisso® in late-stage non-small cell lung cancer (NSCLC) were published in an abstract at the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting, taking place June 2-6, 2023 in Chicago, IL and online.

"We are thrilled to have our abstract, which reports positive results from the Phase 1 portion of our Acclaim-1 clinical trial, published at the ASCO Annual meeting," said Mark Berger, MD, Chief Medical Officer at Genprex. "We are encouraged by the favorable safety profile of REQORSA, as well as the preliminary efficacy data we have observed, and we believe this data will support our advancement to the Phase 2 portion of the clinical trial."

Details of the abtract are below:
Abstract Number: e15081
Title: ACCLAIM-1 dose escalation: Determination of quaratusugene ozeplasmid and osimertinib recommended phase 2 dose (RP2D)
Session Title: Publication Only: Developmental Therapeutics—Molecularly Targeted Agents and Tumor Biology
Track: Developmental Therapeutics—Molecularly Targeted Agents and Tumor Biology

The abstract reports preliminary results from eight patients in Genprex's Phase 1 portion of its Acclaim-1 clinical trial evaluating REQORSA Immunogene Therapy (quaratusugene ozeplasmid) with Tagrisso (osimertinib) in patients with advanced, EGFR mutant NSCLC whose disease progressed after Tagrisso. REQORSA was generally well tolerated, as there were no dose limiting toxicities. Full safety and efficacy data on the Phase 1 portion of the study will be presented at an upcoming medical meeting.

While the Phase 1 portion of the clinical trial is designed primarily to assess safety, promising efficacy results were also observed. One patient at the 0.06 mg/kg dose level, previously treated with carboplatin, pemetrexed, and osimertinib, had a partial remission (PR) by investigator evaluation and treatment is ongoing after 16 cycles, which is approximately 10.5 months. Another patient at the 0.09 mg/kg dose level, previously treated with osimertinib, has stable disease and treatment is ongoing after 14 cycles, or approximately 9 months. The extended and ongoing progression free survival (PFS) of each of these patients is significantly greater than the median PFS observed from treatment with osimertinib alone in this treatment setting in several prior clinical trials¹ and is consistent with long-term PFS seen in prior clinical trials of REQORSA. PFS is the primary endpoint of both the Phase 2 expansion portion and the Phase 2 randomized portion of the Acclaim-1 trial.

"Demonstrating a favorable safety profile substantially de-risks the REQORSA development program and is a major accomplishment for Genprex," said Rodney Varner, Chairman, President and Chief Executve Officer of Genprex. "It is encouraging that several patients who were progressing on their previous therapy are now having long periods of response and stable disease in the Phase 1 portion of the study. We wish to thank the patients and investigators participating in our clinical trials and our investors who make it possible to move our drug candidates forward toward availability for patients in need."

^1. CHRYSALIS-2 NSCLC clinical trial data reported at ASCO 2022

About Acclaim-1
The Acclaim-1 clinical trial is an open-label, multi-center Phase 1/2 clinical trial evaluating the Company's lead drug candidate, REQORSA, in combination with Tagrisso in patients with late-stage NSCLC with activating epidermal growth factor receptor ("EGFR") mutations whose disease progressed after treatment with Tagrisso.
The enrollment of the dose escalation Phase 1 portion of the Acclaim-1 trial has been completed.  The Phase 2 expansion portion of the study is expected to enroll approximately 66 patients, half of whom will have received only Tagrisso treatment and the other half will have received Tagrisso treatment and chemotherapy, to determine toxicity profiles of patients with different eligibility criteria, as well as efficacy and other endpoints. There will be an interim analysis following the treatment of 19 patients in each cohort.  The Phase 2 randomized portion of the study is expected to enroll approximately 74 patients to be randomized 1:1 to receive either REQORSA and Tagrisso combination therapy or platinum-based chemotherapy. The primary endpoint of the Phase 2 portion of the trial is progression-free survival, which is defined as time from randomization to progression or death. An interim analysis will be performed at 25 events.

About REQORSA® Immunogene Therapy
REQORSA Immunogene Therapy (quaratusugene ozeplasmid) for non-small cell lung cancer (NSCLC) uses Genprex's unique, proprietary ONCOPREX® Nanoparticle Delivery System, which is the first systemic gene therapy delivery platform used for cancer in human clinical trials. The active agent in REQORSA is a plasmid that expresses the TUSC2  tumor suppressor gene. REQORSA consists of the TUSC2 gene expressing plasmid encapsulated in non-viral lipid nanoparticles made from lipid molecules with a positive electrical charge. REQORSA is injected intravenously and specifically targets cancer cells. Once REQORSA is taken up into a cancer cell, the TUSC2 gene is expressed, and the TUSC2 protein is capable of restoring certain defective functions arising in the cancer cell. 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.

Tagrisso® is a registered trademark of AstraZeneca plc and is its top-selling drug with 2022 sales of more than $5 billion.

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 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). 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.

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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; 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.

Genprex, Inc.
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SOURCE Genprex, Inc.