From very early on, researchers and doctors have dreamed of using the body’s own immune system to fight cancer. The big question has been why doesn’t the immune system attack the tumor cells that invade healthy tissue?

The really good news is that finally science is catching up with this vision.

Therapeutic cancer vaccines that can actually activate a patient’s immune system against a cancer and help prevent a recurrence are finally starting to become a reality. Our hope is that we will be able to achieve the early promise of cancer vaccines and use them as a part of our standard arsenal in fighting cancer.

“We really are in a transformative moment,’’ said Dr. Glenn Dranoff, professor of medicine at Harvard Medical School and a medical oncologist and immunologist at the Dana-Farber Cancer Institute. Men with advanced prostate cancer have been the first to realize a benefit from immunotherapy with the vaccine Provenge, a therapeutic vaccine that recently received federal approval. The results of the critical phase 3 trial showed that Provenge both was safe and extended survival in men with advanced prostate cancer

Not too long after the approval of Provenge another cancer vaccine received FDA approval, Yervoy (ipilimumab). It was approved for people with metastatic melanoma, a deadly skin cancer. Cancer generally limits the body’s immune response to a tumor; Yervoy turns the immune system back on, enhancing the immune system’s ability to kill cancer cells. Yervoy is now in clinical trials to treat advanced prostate cancer.

The even better news is that currently there are many other potential cancer vaccines under development including trials for patients with breast, prostate, lung, kidney, colon, cervical, brain, and pancreatic cancers, as well as lymphomas. Like in Yervoy, if a trials is shown to be effective in one type of cancer they will probably then be tried to combat other cancers.

From an economic standpoint, which is important because it drives future investment in other potential vaccines, the market initially responded enthusiastically when Provenge was approved. Along with a very positive stock market response came additional commitments from other researchers to develop other cancer vaccines.

Despite the initial economic fervor seen for Dendreon (Provenge’s developer) the economics have cooled because initial sales figures fell well below expectations. But the drug’s $200 million or so in revenue still puts its first-year sales among the top five or six ever for a cancer product, according to the company president and chief executive, Dr. Mitchell H. Gold.

Both approved vaccines, Provenge and Yervoy, come with substantial price tags: Provenge is on the market for $93,000 for three treatments and Yervoy is $120,000 for four treatments. Despite these high prices most insurance carriers as well as Medicare cover the costs. If you look at my prior analysis you will see that in reality these vaccines are in line with chemotherapy’s costs (Provenge, It Isn’t Over Priced, Its Actually A Bargain Basement Product and worthwhile because they block cancer from spreading, recurring and they extend life.

According to Estuardo Aguilar-Cordova, chief executive of Advantagene Inc. which is developing another prostate cancer vaccine, ProstAtak® which is in phase 3 trials, “Radiation or surgery after initial diagnosis costs about $50,000 and treating cancer that recurs can easily cost $500,000. He went on to say “It’s a lot less expensive for our society as a whole to prevent the disease than to treat the disease. That’s part of the promise of cancer vaccines.”

In an early trial designed to look at safety, ProstAtak® cut the prostate cancer recurrence rate from 30 percent to 10 percent, Aguilar-Cordova said. His company has just begun a larger national trials that include at UMass Memorial Medical Center in Worcester. The trial should help determine how many patients remain recurrence-free, and for how long.

Cancer vaccines seem to work best as a supplement to treatment as opposed to replacing existing treatments. Many scientists believe that multiple vaccines may work better then a single vaccine.
It is our hope and our belief that over time vaccines will improve substantially. “This is really the first wave and proof-of-principle kind of stuff,’’ said Dr. Philip Kantoff, chief clinical research officer at Dana-Farber and a professor at Harvard Medical School.

More potent vaccines that extend life spans even longer than the current ones are certainly coming, said Darrell J. Irvine, an associate professor at MIT’s David H. Koch Institute for Integrative Cancer Research. On the flip side of the coin Irving said “Before, our cancer vaccines were so weak, there wasn’t much concern that they could trigger a systemic immune reaction, like the autoimmune diseases psoriasis, multiple sclerosis, or rheumatoid arthritis…. Now, perhaps we’re reaching the stage where the threat of autoimmunity will be something to worry about.’’

There remain many unanswered questions about how our immune system works. As Irvine indicated, as we increase the vaccine’s potency they might also pose greater risks.

We are on the cusp of great potentials. Led by Provenge, cancer vaccines will continue to improve and provide additional life extension.

Joel T Nowak, M.A., M.S.W.