• Recommendation to Advance to Increased Dose in Third and Final Cohort of Phase 1 Portion of Trial Indicates Favorable Safety Profile of Novel Gene Therapy in Solid Tumor Cancer

AUSTIN, Texas, Dec. 14, 2022 /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 the Safety Review Committee (SRC) has approved continuation to the third and final cohort in the dose escalation Phase 1 portion of the Acclaim-1 Phase 1/2 clinical trial of REQORSA® in combination with Tagrisso® (osimertinib) to treat late-stage non-small cell lung cancer (NSCLC). In 2020, the combination of REQORSA and osimertinib received U.S. Food and Drug Administration's (FDA) Fast Track Designation for treatment of the Acclaim-1 patient population.

Acclaim-1 is an open-label, multi-center Phase 1/2 clinical trial evaluating the Company's lead drug candidate, REQORSA Immunogene Therapy, in combination with Tagrisso (osimertinib) in patients with late-stage non-small cell lung cancer (NSCLC) whose disease progressed after treatment with Tagrisso.

The SRC is comprised of three physicians who are principal investigators in the trial. The SRC may recommend that the trial continues at the same dose or at a lower dose, that it escalates to a higher dose, or that the study be terminated altogether due to safety concerns.

"The SRC's recommendation to increase the dosing of REQORSA is further confirmation of its favorable safety profile and it enables us to advance Acclaim-1 into the final cohort of the Phase 1 dose escalation portion of the study," said Mark Berger, M.D., Chief Medical Officer of Genprex. "We look forward to completing enrollment of this final cohort in the first quarter of 2023."

The Accaim-1 trial includes up to three sequential dose escalation cohorts that will treat study participants with REQORSA intravenously on Day 1 in addition to osimertinib 80 mg fixed dose oral daily tablet during 21-day treatment cycles until disease progression or unacceptable toxicity. The first group received REQORSA IV infusion at 0.06 mg/kg, the second group received 0.09 mg/kg, and the third group will receive 0.12 mg/kg. 

Following successful completion of the Phase 1 dose escalation portion of the Acclaim-1 study, the Company will advance into the dose expansion portion of the study, which will evaluate the toxicity profile of REQORSA in combination with Tagrisso in patients with different eligibility criteria, and will also evaluate efficacy and other endpoints.

"The principal advantage of adding the dose expansion portion to Acclaim-1 is to gain efficacy data earlier than we would otherwise have received it from the Phase 2 portion of the study. We also will receive this data in the two distinct patient populations represented by the two expansion cohorts, which we believe will further increase the likelihood of a successful Phase 2 trial," added Dr. Berger. 

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. Genprex expects the dose escalation Phase 1 portion of the Acclaim-1 trial to enroll up to 18 patients to determine the maximum tolerated dose of the combination. The dose expansion Phase 1 portion of the study will then enroll 66 patients, half of whom will be patients who had received only prior Tagrisso treatment and the other half patients who had received prior 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 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 Tagrisso monotherapy. 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.

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 plasmid portion of REQORSA contains the TUSC2 gene, a tumor suppressor gene. REQORSA consists of the TUSC2 gene containing plasmid encapsulated in a nanoparticle made from lipid molecules with a net positive electrical charge. REQORSA is injected intravenously and is preferentially taken up by 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 its largest selling drug with 2021 sales of over $5 billion.

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 the Company believes is the first systemic gene therapy delivery platform used for cancer in humans. ONCOPREX 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 body. The Company's lead product candidate, REQORSA® (quaratusugene ozeplasmid), is being evaluated as a treatment for non-small cell lung cancer (NSCLC) (with each of these clinical programs receiving a Fast Track Designation from the Food and Drug Administration) and for small cell lung cancer. Genprex's diabetes gene therapy approach is comprised of a novel infusion process that uses an endoscope and an adeno-associated virus (AAV) vector to deliver Pdx1 and MafA genes to the pancreas. In models of Type 1 diabetes, the genes express proteins that transform 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 Type 2 diabetes, where autoimmunity is not at play, it is believed that exhausted beta cells are also rejuvenated and replenished.

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

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, 2021.

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: the timing and success of Genprex's clinical trials and regulatory approvals, including the extent and impact of the COVID-19 pandemic; 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; Genprex's commercial and strategic partnerships, including those with its third party 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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