Working together, ZIOPHARM and Intrexon are on the path to treating melanoma
The skin is the body’s largest organ, protecting other vital organs and shielding the body from heat, injury and infection. It also protects the body from damage caused by ultraviolet radiation from the sun, manufactures vitamin D and stores water and fat.
Skin cancer is the most common type of cancer in the United States with approximately 2 million people per year diagnosed with some form of the disease. A smaller number, 75,000, of these Americans were diagnosed with melanoma, the deadliest form of skin cancer, in 2013. Nearly 10,000 of those diagnosed this year died from the disease.
Current treatments for melanoma include surgery, chemotherapy, photodynamic (laser) therapy and radiation therapy. For some with the most advanced stages of melanoma, biologic therapies may improve the body's natural defense (immune system response) against cancer. There are currently two biologics approved in the treatment of melanoma – interferon, which can slow the growth of melanoma cells and interleukin-2, which can help the body destroy cancer cells.
Intrexon and ZIOPHARM have partnered to create the next generation of biologics, advancing the treatment of melanoma to include targeted and highly regulatable therapeutics. ZIOPHARM’s therapy employs an adenoviral vector to deliver, directly into the patient's cells, a gene which expresses Interleukin-12 (IL-12). IL-12 is a potent, naturally occurring cytokine central to the initiation and regulation of cellular immune responses. To date, IL-12 has had limited use as a therapeutic agent due to significant toxic effects that occur with systemic administration.
Unique to the IL-12 therapy developed by Intrexon and ZIOPHARM is tight regulation of IL-12 production within cells through Intrexon’s RheoSwitch Therapeutic System® (RTS®) platform, a gene switch controlled by an orally administered small molecule activator ligand (AL).
ZIOPHARM recently presented positive Phase I data at the world’s premier clinical oncology meeting – the 2013 Annual Meeting of the American Society of Clinical Oncology. For the study, Ad-RTS-IL-12, an adenoviral vector engineered to express IL-12 under RTS® control was injected into the tumors of patients with advanced melanoma. Expression of IL-12 was controlled through the administration of an oral AL.
ZIOPHARM observed improvement in lesion appearance in 71 percent of patients dosed at the two highest dose levels. In addition, after receiving Ad-RTS-IL-12 and the activator ligand this group of patients expressed high levels of IL-12 and interferon, both of which boost immune response to cancer.
These promising results demonstrate the potential for regulatable therapies to harness the power of the immune system to elicit an anti-cancer response. The Phase I study observations are the foundation for an ongoing Phase II study with Ad-RTS-IL-12 that will focus on optimizing a dosing schedule.