Scientists have discovered an unlikely ally when using immunotherapy to fight cancer.
Two teams have found that there is considerable evidence which suggests that gut bacteria, and the amount of it we have in our bodies, can actually influence how well a tumour shrinks.
It’s well documented that the bacteria in our gut plays a key role, not only for digestion but in helping support our immune system.
The fascinating study echoes initial studies around two years ago which found that a certain type of gut bacteria reacted well when a powerful new type of cancer drug was administered.
Now the initial problem with this study was that it was carried out on mice, and while mice continue to be a reliable testbed for cancer research it wasn’t clear if the same effects could be replicated in humans.
The two new studies however, published in the journal Science, have now discovered a clear link by focusing on the relationship between the bacteria in our gut and a for of immunotherapy known as PD-1.
In one of the studies, the team examined 249 lung, kidney and bladder cancer patients. Now 69 of those took antibiotics for general health reasons such as dental work or an infection. All 69 patients had taken these antibiotics either before, or soon after starting PD-1 treatment.
The differences in responses were striking. The patients who were on antibiotics (which can disrupt gut bacteria) either relapsed sooner or didn’t live as long as the patients who hadn’t taken the antibiotics.
They found that one bacteria in particular was responsible for the highest increase in response.
Interestingly the second team found an altogether different bacteria was boosting the immunotherapy treatments suggesting that actually, a highly diverse microbiome can make a huge impact on the effects of this form of treatment.
Immunotherapy is a form of treatment that rather than directly attacking the cancer, almost supercharges the immune system in the body giving it both the strength to fight the cancer while also helping it target the tumour.
Jennifer Wargo of MD Anderson Cancer Center in Houston, Texas and leader of the second study believes the findings have “tremendous implications,” for the future of certain immunotherapy treatments.
Laurence Zitvogel, leader of the first study from the Gustave Roussy Cancer Campus in Villejuif, France is equally as excited about the findings and believes that just by avoiding antibiotics patient responses could be boosted from 25% to 40%.