One Big Question: How close are we to a cancer vaccine?
Earlier this year we reported on new research that focused on training the body's own immune cells to fight cancer through a process known as adoptive immunotherapy. The process involves removing immune-system white blood cells known as T-cells, genetically modifying them to recognize certain proteins involved with cancer cells, then injecting them back in their body where they could basically hunt down and destroy tumors. In the study on which we reported, the technique was successful in destroying blood cancer in 93 percent of the patients involved in a clinical trial.
While that study was focussed specifically on blood cancer in particular, T-cell therapy has shown success with regards to other types of cancer and may, in fact, one day lead to a cancer vaccine that would train our bodies to recognize and destroy cancer cells if they invade.
One company working on such a vaccine is Florida-based company TapImmune. So we got ahold of TapImmune's president and COO John Bonfiglio and put this question to him as part of our ongoing series called One Big Question:
"How close are we to having a cancer vaccine that people can actually get from their doctors?"
Here's what he had to say:
The idea of developing cancer vaccines that target tumors or metastatic disease has been proposed for many years. Several companies have synthesized cancer vaccines and completed clinical studies with marginal success at best.
Science, however, is an iterative process and the failures of the past could indeed lead to a viable vaccine for certain cancers. TapImmune, Inc. is leading the charge in this exciting new era of vaccine development specifically designed to target tumors and metastatic disease. The company is working diligently to bring to market agents for ovarian and breast cancer.
There are approximately 30,000 ovarian cancer patients newly diagnosed every year in the US alone. More than 14,000 will die from the disease. Just as sobering, more than 41,000 people – men and women – will die this year from breast cancer.
In the last several years, the science of immuno-oncology has begun to catch up to the ideas of how to develop such a vaccine. There are known to be three major components necessary to develop a strong immune response against cancer – the first is the activation of killer T-cells (CD8+ cells) against a specific target on a cancer cell. This has been known for quite some time and many vaccines that were tested earlier were designed to work by activating these cells.
What has become apparent recently is the need to activate helper T-cells (CD4+ cells). These cells, together with the CD4+ cells, have been found to be essential to generating an immune response strong enough to have a therapeutic effect against cancer. The last component is the ability of the vaccine to generate memory cells capable of reactivating against metastatic disease. Recent early stage human clinical studies have shown that the TapImmune lead product, TPIV 200, may have all three key components.
The development of a T-cell vaccine is at least five to 10 years from being approved. The process will begin with the clearance of a therapeutic vaccine designed to treat patients with cancer and then progress to treating potential patients prophylactically. This is a necessary progression due to regulatory requirements as well as the time and expense to complete clinical trials for a prophylaxis indication.
TapImmune has initiated a comprehensive clinical program that includes a therapeutic program and we are also collaborating with the Mayo Clinic on early development of a prophylactic vaccine.
We are also working with Memorial Sloan Kettering Cancer Institute in New York on a significant trial that combines TPIV 200 with AstraZeneca's checkpoint inhibitor, durvalumab. We expect to start an additional Phase II study in ovarian cancer patients who are responsive to platinum, in an approach to provide maintenance therapy that will reduce cancer relapse and extend progression-free survival. We received Fast Track Designation for TPIV 200 for this indication from the US FDA in February of this year.