A fecal transplant has enabled patients with advanced melanoma to respond to immunotherapy treatments to which their tumors had previously resisted.
- Patients who were resistant to melanoma treatment with immunotherapy received a fecal transplant
- The changes made to the composition of their microbiome have enabled several of them to respond to treatments.
- It is a new therapeutic avenue for the treatment of certain cancers
The intestinal microbiome could be a therapeutic target against cancer. This is the conclusion reached by researchers from the National Cancer Institute and the University of Pittsburgh who used fecal transplantation on patients with immunotherapy-resistant melanoma. Six of them, out of fifteen, experienced a reduction of the tumor or a stabilization of the disease in the long term. This study was published on February 4 in Science.
These six patients with advanced melanoma did not initially respond to immunotherapy treatments, including when these were combined with other drugs. After receiving a faecal microbiota transplant from a patient who had responded to immunotherapy, they showed a decrease in immune system molecules associated with treatment resistance and an increase in biomarkers associated with response to this processing.
No disease progression
Concretely, these patients showed no progression of the disease one year after this fecal transplant which allowed a better response to immunotherapy. The researchers observed biological changes in them with modification of the composition of their microbiome explaining this phenomenon.
“Immunotherapy drugs called PD-1 and PD-L1 inhibitors have benefited many patients with this type of cancer but we need new strategies to help those whose cancers are not responding,” says Dr Giogio Trinchieri , participating in this study. Hence the idea of this clinical trial using a faecal transplant.
The grafts were collected from patients who also had advanced skin cancers and who had responded to pelmbrolizumab (an immunotherapy drug). They were analyzed to ensure that they could not transmit infectious agents and were administered to patients participating in the trial by colonoscopy.
Increased numbers of bacteria associated with T-cell activation
“The results show that introducing certain faecal microorganisms into a patient’s colon can help the patient respond to drugs that improve the immune system’s ability to recognize and kill tumor cells,” Dr. Trinchieri. After analyzing the microbiome of the six patients whose cancers had improved or stabilized, it appeared that it showed an increased number of bacteria associated with the activation of T lymphocyte immune cells.
“If further research identifies the microorganisms essential for a good response to immunotherapy, it may be possible to deliver them directly to patients who need them without resorting to fecal transplantation,” concluded Giorgio Trinchieri.
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