On April 12, 2021 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 collaborators presented positive preclinical data for the combination of TUSC2 immunogene therapy (REQORSA) in combination with chemotherapy and immunotherapies for the treatment of non-small cell lung cancer (NSCLC) (Press release, Genprex, APR 12, 2021, View Source [SID1234577913]). Collaborators also presented positive preclinical data for the use of REQORSA in combination with targeted therapies for the treatment of NSCLC. These data were presented in two presentations at the 2021 American Association of Cancer Research (AACR) (Free AACR Whitepaper) annual meeting. The TUSC2 gene is a tumor suppressor gene and is the active agent in REQORSA.
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"We are pleased to have these positive data that provide further support for the therapeutic potential of REQORSA in combination with immunotherapies and targeted therapies in NSCLC presented before an audience of the world’s leading cancer researchers. These data are particularly encouraging as we look to initiate our upcoming combination Acclaim-1 and Acclaim-2 clinical trials of REQORSA in NSCLC," said Rodney Varner, President and Chief Executive Officer of Genprex. "We know that many patients inevitably develop resistance to immune checkpoint blockade therapy or EGFR-TKI therapy. These data show that REQORSA in combination with immunotherapies and targeted therapies may provide enhanced efficacy in NSCLC that has become resistant to these regimens, offering hope to a large patient population who currently has limited treatment options."
Featured Genprex-supported posters presented at AACR (Free AACR Whitepaper) 21 include:
Oral Presentation:
Session: MS.IM02.02 – Overcoming Resistance in the Tumor Microenvironment: Novel Immunomodulatory Agents
Title: "TUSC2 immunogene therapy enhances efficacy of chemo-immune combination therapy and induces robust antitumor immunity in KRAS-LKB1 mutant NSCLC in humanized mice"
Poster Number/Channel: #76/Channel 03
Presentation Date/Time: April 10, 2021 from 2:50-3:00 p.m. ET
Presenters: Ismail M. Meraz, Mourad Majidi, RuPing Shao, Feng Meng, Min Jin Ha, Elizabeth Shpall, Jack A. Roth. University of Texas MD Anderson Cancer Center, Houston, TX
Poster Presentation:
Session: PO.ET03.01 – Drug Resistance in Molecular Targeted Therapies
Title: "Overcoming resistance to osimertinib by TUSC2 gene therapy in EGFR mutant NSCLC"
Poster Number: #1105
Presentation Date/Time: April 10, 2021 from 8:30 a.m. – 11:59 p.m. ET
Presenters: Ismail M. Meraz, Mourad Majidi, RuPing Shao, Lihui Gao, Meng Feng, Huiqin Chen, Min Jin Ha, Jack A Roth
The first presentation, entitled "TUSC2 immunogene therapy enhances efficacy of chemo-immune combination therapy and induces robust antitumor immunity in KRAS-LKB1 mutant NSCLC in humanized mice," showed that the triple combination of chemotherapy, immunotherapy (immune checkpoint blockade) and REQORSA demonstrated strong antitumor efficacy and induced robust antitumor immunity in KRAS-LKB1 (KL)-mutant NSCLC in clinically relevant humanized mice models.
In this study, researchers evaluated the antitumor immune response of a chemo-immunotherapy combination with REQORSA on highly metastatic KL-mutant human lung cancer in humanized mice. Humanized mice were first treated with REQORSA, immunotherapy nivolumab (Opdivo), or the combination. The results showed synergistic antitumor activity with the combination. Next, humanized mice were treated with REQORSA, immunotherapy pembrolizumab (Keytruda), or the combination. When REQORSA was added to the chemotherapy and immune checkpoint blockade combination, metastases regression was significantly greater than either REQORSA, REQORSA and pembrolizumab, or chemotherapy and pembrolizumab treatments.
"KRAS is a frequent genomic driver in lung adenocarcinoma,", said Michael Redman, Executive Vice President and Chief Operating Officer of Genprex. "LKB1 (also known as STK11) is a distinct subgroup of KRAS-mutants and is the most prevalent genomic driver of resistance to PD-1 blockade in KRAS-mutant lung cancer."
The second poster, entitled "Overcoming resistance to osimertinib by TUSC2 gene therapy in EGFR-mutant NSCLC," showed that REQORSA in combination with targeted therapy osimertinib (Tagrisso) demonstrated synergistic antitumor efficacy in EGFR mutant osimertinib resistant NSCLC tumors in H1975-OsiR isogenic tumors. Researchers also found that the upregulation of PDK1 was associated with osimertinib resistance.
In this study, researchers developed an osimertinib resistant H1975-OsiR isogenic cell line through continuous exposure to osimertinib. Xenograft tumors from both H1975-parental and H1975-OsiR cells were developed in NSG mice and were treated with osimertinib. Synergistic antitumor activity of REQORSA and osimertinib was found in H1975-OsiR tumors. The combinations showed a robust antitumor effect compared with single agent treatment groups. Reverse phase protein array (RPPA) data showed that PDK1 was significantly upregulated in the REQORSA and osimertinib group when compared with either control, osimertinib alone or REQORSA alone treated H1975-OsiR tumors, indicating that PDK1 may be associated with osimertinib resistance. No PDK1 inhibitor effect was found in the REQORSA treated group, implicating the specific role of PDK1 in osimertinib resistance.