At the ACGT anniversary gala in April, Robert Vonderheide, MD, DPhil, the Hanna Wise Professor in Cancer Research and newly appointed Director of the Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, briefed the audience on the progress of his research using immunotherapy for pancreatic cancer and other solid tumors. ACGT first supported Dr. Vonderheide’s innovative immunotherapy research for brain tumors, in 2003.
Now Dr. Vonderheide aims to develop a cancer vaccine, which may prove applicable to all human cancers. His team has identified an enzyme – Telomerase – present in all cancers. Known as a universal tumor antigen, telomerase has the potential to serve as a homing beacon for the immune system’s killer T-cells. Early trials indicate a robust response, without toxicity, and also measurable survival benefits over time.
A vaccine for cancer? Yes, it is possible, but not quite what you know of a vaccine. A cancer vaccine does not introduce live pathogens into the body; instead, modified genetic material is injected to essentially open the door for the body’s natural immune system to go into action
Vaccination has a long history. The US Vaccine Agency was established in 1813 and predominantly targeted viruses. Polio was subsequently the most prominently known successful vaccination program, in addition to smallpox, measles, influenza, and others that destroyed so many lives.
The first polio epidemic was reported in 1894 and by the early 20th century, hundreds of thousands died every year, mostly children. A virus was identified as the source of the disease, and subsequently three different viruses are known to cause polio. In 1935 the first vaccine trials began, and in 1953, Dr. Jonas Salk gave his vaccine to his own family before approval. By the end of the 1960s, the disease was eliminated in the industrialized nations, and, in the 1970s, routine vaccination was introduced throughout the world. Today, the global incidence of polio is down to 1%.*
Two types of vaccines are used widely to protect against disease, both designed to stimulate the immune system but differently. The polio vaccine is based on Specific immunity – a targeted response to a specific pathogen. An inactivated live pathogen, or segments of the virus, is introduced into the body so the immune system recognizes the threat. A Non-Specific vaccine focuses on what is called Innate Immunity – the body goes on alert to foreign materials. In both cases, the body’s natural killer T-cells are released and regulatory T-cells remain on guard against further invasion.
There are currently two cancer vaccines approved by the FDA: Gardasil and Cevarix. Both cervical cancer vaccines are used to prevent infection with two high-risk HPV strains, which cause nearly 70 percent of cervical cancers. Gardasil is said to prevent infection with the strains that cause nearly 90 percent of genital warts. The CDC recommends these vaccines for girls ages 11 to 12, which allows the immune system to develop antibodies before exposure to HPV.
Dr. Vonderheide envisions a non-specific [Innate] vaccine for cancer, a vaccine using modified genetic material to alert the immune system. It is believed now that all cancers contain a marker – the universal tumor antigen and once all its properties are identified, it will be possible to build a vaccine to seek out and destroy cancer by zeroing in on the antigen, and then remain in the body to protect against any further threats.
We live in a world without polio and it is possible, sooner than you might think, to live in a world without cancer. ACGT Research Fellows are paving the way.