Cancer: microbiome transplant boosts immunotherapy success

Image of the intestines Photo: Elionas2 Pixabay

For the first time in the world, a team from Israel successfully controlled malignant tumors with an intestinal treatment. New hope against evil.

Modifying the gut microbiome can reprogram the immune system to attack malignant tumors. This was reported by a unique clinical trial conducted at the Sheba Medical Center in Israel.

The results were published in the scientific journal Science and the study was carried out by a research team led by senior gastrointestinal oncologist Ben Boursi, senior oncologist Gal Markel, and student Erez Baruch.

“For the first time in history, we successfully fight cancerous tumors by changing the gut microbiome. Currently, immunotherapy works for only 40 to 50 percent of patients but today we can anticipate that with the help of this revolutionary treatment, we will see as many patients as possible transform from non-responders to responders,” said Dr. Boursi. .

The researchers performed fecal microbiota transplantation (FMT) in a dozen terminally ill patients with metastatic melanoma who had not responded to immunotherapy and had exhausted all other existing treatment options.

“In the first phase, we eradicated the patient's existing microbiome after which we transplanted gut microbiota from cancer survivors who had had melanoma but had responded well to immunotherapy and who had been cancer-free for at least a year,” he explained. explained.

Relevant results

Half a month after the donor microbiome had been introduced through a colonoscopy - and the patients had completely absorbed the donor microbiota - immunotherapy was resumed.

For one quarter, patients were given odorless, tasteless pills containing the same bacteria.

In two of the study participants, the tumors shrank significantly. One patient's tumor disappeared and, two years later, it had not grown back.

“To see a 30 percent response is really extraordinary,” Boursi told ISRAEL21c, considering the participants' terminal condition and their previous failed treatments.

Most significantly, Boursi and his team saw evidence of an increased immune response at the cellular level, as well as in the gene expression profiles of the three patients who responded well.

Boursi said he believes some of the transplant patients did not respond to immunotherapy due to genetic changes in their tumors, meaning the microbiome is not the only factor that may affect response to treatment.

“While we emphasize the clinical benefit of the treatment, we must remember that it is the icing on the cake. Our main objective was to see if the treatment is safe and feasible,” described the specialist.

Now that microbiome transplantation has been shown to be “simple, safe and relatively inexpensive,” Boursi and the Sheba team are testing it in other patients with melanoma and lung cancer, one of the most common causes of death from cancer.

no side effects

Whether or not this affected the success of the immunotherapy, there was another unexpected benefit: While many of the trial participants had suffered serious side effects during their previous failed round of immunotherapy, the microbiota transplant treatment showed none of that. .

“That alone is a tremendous achievement,” Boursi said. Now, the team is exploring whether the transplant treatment could be used specifically to help alleviate the side effects of immunotherapy.

The scientists said their continued laboratory work can help them identify cancer patients who will benefit most from the therapy as well as identify the most appropriate donor for each patient. They also hope to define the biological pathway underlying the change in immune responsiveness.

What is it about the gut microbiome that can make a difference in the success of immunotherapy? “We know that the gut microbiome has many functions in human health, and one is the development of the immune system. An example: in germ-free mice, the immune system does not develop correctly.”

Other authors of the study are from Tel Aviv University, Shamir Medical Center, Hadassah Medical Center, Bar-Ilan University and Assuta University Hospital in Ashdod.

Source: ISRAEL21c

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