‘Promising’ cancer treatments on the horizon
JAZELLE HUNT | 7/7/2014, 1:17 p.m.
WASHINGTON – Cancer is the nation’s second-leading cause of death for both Blacks and Whites. While there is no known cure for cancer, a flurry of FDA approval requests to treat the most threatening cancer cases has researchers optimistic that progress is being made toward an eventual cure.
As Dr. William Chambers, national vice president of Extramural Research for the American Cancer Society, explains, “Things are happening on all fronts, not just in research, but in clinicals as well.”
Much of the developments are around immunotherapy, an established concept that includes all treatments that employ or manipulate a patient’s own immune system to target the illness.
Researchers seem to be most interested in improving cancer vaccines, which can be preventative (prophylactic), or used as treatment (therapeutic). Two prophylactic vaccines that fight viruses known to cause cancer are already on the market, i.e., the HPV and hepatitis B vaccines. But so far, such vaccines only work for the small subset of cancers caused by viruses. Still, this hasn’t stopped researchers from trying to create a vaccine against cancer itself.
“Most effort has been toward therapeutic vaccines, which seek to immunize those who already have cancer,” Chambers said. “But because there are so many factors, it’s tough to provoke an immune response.”
Therapeutic vaccines either boost overall immune response, or teach a patient’s immune system to recognize and target afflicted cells.
Provenge, the first, and currently only, FDA-approved therapeutic vaccine, does the latter. Provenge is used for prostate cancer and has been shown to add close to four more months of life for near-terminal patients. Although the mortality rate is low for prostate cancer, Black men are more than twice as likely as White men to die from it. They are also 60 percent more likely to contract it in the first place, according to the ACS.
Provenge is what’s known as a dendritic cell vaccine. It is created from a patient’s own immune cells and cancer cells. The immune cells are enhanced for growth, “taught” to recognize those cancer cells, and re-implanted into the patient, where the cells multiply and alert the immune system to fight cancer cells like the one sampled.
On another front, Pfizer is partnering with a French pharmaceutical company to create a standardized tumor-cell-based vaccine. This type of treatment samples a tumor cell and reengineers it to be more detectable to the immune system; when the cell is reintroduced to a patient, the immune system recognizes and attacks all cells like it. Unlike customized vaccines such as Provenge, this treatment uses a random tumor sample from a patient to create a generalized vaccine that can be used in anyone with a comparable diagnosis.
Pfizer’s is slated to begin clinical trials for this treatment next year.
In addition to vaccines, there are monoclonal antibodies, man-made proteins engineered to infiltrate unchecked cancer cells, and make them visible to the body’s immune system. AstraZeneca, for example, is poised to release such a treatment, known as MEDI4736. In its first round of clinical trials, tumors shrank in 19 percent of patients (diagnosed with a few different cancers), and another 39 percent had their cancer stabilize for a year or longer. The treatment is currently in its final round of trials.