Immunotherapy is a relatively nascent weapon in the fight against cancer. Instead of relying on more conventional chemotherapy treatments, this technique encourages the body to use its own immune system to destroy cancerous tissue. It’s been seeing some success recently, and a new drug, IMM-101, has been shown to extend the lives of people with severe pancreatic cancer.
Although this is clearly wonderful, there are two aspects of this trial that stand out as truly remarkable. Firstly, the drug – which is made from heat-treated bacteria – produces no side-effects in patients whatsoever. Secondly, it can successfully treat metastatic cancer, the type wherein tumors have spread all throughout the body and where untreated survival rates are incredibly low.
“To me it’s really exciting,” coordinating researcher Angus Dalgleish, professor of oncology at St George’s, University of London, told The Guardian. “This is the first time we have got an immunotherapy that is a really good candidate to help control pancreatic cancer, which is one of the biggest killing diseases. Its incidence nearly matches its mortality. It is absolutely staggering.”
The trial of 110 people was relatively small, but the potential for the drug is extreme. The fatality rate for this specific cancer, which is the world’s 12th most common type, is incredibly high.
Only 18 percent of those suffering from advanced pancreatic cancer are alive after one year, and this drops to 4 percent after five years. The risk is greatest for the very old, but excessive smoking and body fat contributes towards this risk.
Unlike some other immunotherapy drugs, this one isn’t taken as a pill, but injected into the skin. It stimulates the immune system into quickly manufacturing a variety of white blood cells known as T-cells, whose primary job is to attack cells infected with viruses or those that have become cancerous.
Image in text: A micrograph of pancreatic ductal adenocarcinoma, the most common type of pancreatic cancer. KGH/Wikimedia Commons; CC BY-SA 3.0
This is sufficient for those whose pancreatic cancer had spread locally, but for those who have metastatic cancer, this isn’t enough to destroy the protective cellular shielding that has grown around the pancreatic cancer clumps. However, this is where an additional chemotherapy drug, gemcitabine, comes in.
Taken intravenously, this drug cuts a hole through the cellular shield, which allows the masses of T-cells to attack and destroy the tumors. When taken in combination, the patients who had metastatic disease survived on average of 2.6 months longer, but some lived for over a year. One patient died after nearly three years of treatment.
Immunotherapy has made inroads in treating several other cancers, including skin, but pancreatic cancer has long proven to be difficult to treat – by any means. The tumors are deep-rooted and highly shielded, rendering most chemotherapy ineffective. The immune system alone cannot often recognize the tumors as a threat and consequently leave it alone to develop.
As reported in the British Journal of Cancer, IMM-101 stirs it from its slumber, and gets it to ferociously attack the cancer. With no side-effects, there’s little reason why pancreatic cancer sufferers will be wary about taking it.
However, it must be noted that the overall survival benefit is quite small at this stage. In fact, it’s not yet confirmed that the combination of drugs here truly improved life expectancy of patients to a statistically significant degree. “Further research with more patients is needed to develop therapies that can improve survival,” Justine Alford, Cancer Research UK’s senior science information officer, told the Guardian.
Deaths from pancreatic cancer per million persons, circa 2012. Yellows equate to 0 to 9, oranges equate to 10-162, and reds are 163 or above. Chriss55/WHO/Wikimedia Commons; CC BY-SA 4.0