The Power Behind Gene Therapy Drug Combinations

While targeted therapies and immunotherapies have become new options for treating many of today’s most serious cancers, these therapies do have their limitations.

Genprex, a clinical-stage gene therapy company developing potentially life-changing technologies for patients with cancer and other serious diseases, is harnessing the power of a combinational treatment approach that utilizes its leading gene therapy drug candidate, Oncoprex, in combination with approved targeted and immunotherapies in order to overcome treatment limitations and offer patients new treatment options. In January 2020, the U.S Food and Drug Administration granted Fast Track Designation for Genprex’s lead drug candidate, Oncoprex™ immunogene therapy for non-small cell lung cancer (NSCLC) in combination therapy with osimertinib (AstraZeneca’s Tagrisso®).

Targeted Therapies

Targeted therapies work by targeting the cancer or disease’s specific gene, protein or tissue that contributes to the disease1 while sparing normal tissue. This therapy is different from chemotherapies, which usually destroy all dividing cells, irrespectively.

Unfortunately, targeted therapies require patients to have an activating genetic mutation specific to the drug. In NSCLC, the vast majority of lung cancer patients do not have the genetic mutations found in lung cancer that qualify them for targeted therapies, such as the EGFR or ALK gene. One study found that only about 10 percent of NSCLC patients had the EGFR mutation2. In addition, the few patients who do have the right genetic mutation to receive some of the available targeted therapies are likely to develop resistance to these drugs over time3.

To overcome the limitations of targeted therapies, many companies and researchers are studying the combination of approved targeted therapies with potential new drug candidates. The hope of these combinations is to improve outcomes for patients. In fact, Genprex has studied its lead drug candidate, Oncoprex, in combination with erlotinib, an approved targeted therapy for NSCLC. 

Preclinical and clinical data show that Oncoprex works synergistically with erlotinib to help destroy the cancer cells and may help patients who have become resistant to erlotinib alone.

The company’s recent Fast Track Designation by the FDA is for the combination of Oncoprex and osimertinib (marketed as Tagrisso® by Astra Zeneca), a third generation EGFR inhibitor. The company received this designation based on its preclinical data of Oncoprex combined with osimertinib and its clinical trial data for Oncoprex combined with erlotinib. Tagrisso® is AstraZeneca’s highest grossing product, which had worldwide sales in 2018 of $1.86 billion and $3.18 billion in 2019.

Immunotherapies

Immunotherapy is a type of treatment that helps the immune system fight disease4. Biomarker testing can help determine if high levels of PD-1/PD-L1 proteins are detected in the patient, signifying that the body’s immune system is not working to fight cancer or disease as it should. These patients could qualify for approved immunotherapies, however, only about 12 percent of patients benefit from immunotherapies5.

Similar to targeted therapies, immunotherapy combinations are being studied to see how these limitations can be overcome. Genprex is conducting preclinical studies to evaluate Oncoprex in combination with checkpoint inhibitors.

Preclinical data shows that Oncoprex is synergistic with anti-PD1 therapy and could result in a stronger antitumor response compared to either agent alone.  

Additionally, the combination of Oncoprex increased the effectiveness of anti-PD1 checkpoint blockade combined with chemotherapy in a humanized mouse model with lung metastases.

Genprex believes its lead drug candidate in combination with checkpoint inhibitor pembrolizumab may have similar synergistic results for patients.

The Power of Immunogene Therapy Combinations

Genprex is working to provide new treatment options to a larger group of patients who would not otherwise be candidates for targeted therapies or immunotherapies or who have built up resistance to currently approved drugs.

The company’s lead drug candidate, Oncoprex immunogene therapy, is unlike the approved targeted therapies and immunotherapies available today. Because Oncoprex is a gene therapy that also modulates immune activity around the cancer cell, it is poised and positioned to help NSCLC patients who cannot benefit from today’s treatment options. It may also be able to be combined with a variety of approved drugs to improve outcomes for patients in a variety of cancers.

To learn more about the company’s lead drug candidate, please visit the Technology page on Genprex’s website.

*Oncoprex is currently in development and is not FDA approved.

References:

1.  Understanding Targeted Therapy. Cancer.Net. https://www.cancer.net/navigating-cancer-care/how-cancer-treated/personalized-and-targeted-therapies/understanding-targeted-therapy. Published December 5, 2019. Accessed February 20, 2020. 

2. El-Telbany A, Ma PC. Cancer genes in lung cancer: racial disparities: are there any?. Genes Cancer. 2012;3(7-8):467–480. doi:10.1177/1947601912465177.

3. Meyers DE, Bryan PM, Banerji S, Morris DG. Targeting the PD-1/PD-L1 axis for the treatment of non-small-cell lung cancer. Curr Oncol. 2018;25(4):e324–e334. doi:10.3747/co.25.3976  

4. Immunotherapy for Cancer. National Cancer Institute. https://www.cancer.gov/about-cancer/treatment/types/immunotherapy. Accessed February 20, 2020.

5. Haslam A, Prasad V. Estimation of the Percentage of US Patients With Cancer Who Are Eligible for and Respond to Checkpoint Inhibitor Immunotherapy Drugs. JAMA Netw Open. 2019;2(5):e192535. doi:10.1001/jamanetworkopen.2019.2535.