The impact of therapy like chemotherapy not just depends on patients’ body but the effect of a specific drug also depends on the trillions of bacteria in the gut. Experts have said that 100 trillion bacteria that live inside the digestive tract, which is known as the human gut microbiome are essential for extracting nutrients from food. The gut microbiome help boost the immune system response. It can modulate the impact of drugs as well. A new study has linked the gut microbiome in apparently unrelated states from the response to cancer treatments to obesity and a range of neurological issues such as Alzheimer’s disease, Parkinson’s disease, depression, schizophrenia, and autism. Experts have made discrete observations that the gut bacteria can send signs beyond the gut and these signals have large effects on a wide range of target tissues. This study has been done in order to develop new therapies for cancer. Experts have tried to find out whether altering the gut microbiome can help cancer patients. The findings of the new study have been published in the journal called Science.
Experts have transferred the fecal matter from cancer patients who have been responding well to the treatment to those patients who have not been showing any progress after being given immunotherapy. They have found that this novel treatment has been able to reduce the tumors of patients who have been dealing with advanced-stage cancer when other therapies have failed to provide any relief. As per the study, the gut microbiome is linked to the success and failure of many cancer treatments. These treatments involve chemotherapy and immunotherapy along with immune checkpoint inhibitors such as nivolumab and pembrolizumab. Recent studies have shown that the species and population of gut bacteria are responsible for a cancer patient responding to drugs, which are known as immune checkpoint inhibitors.
The new research has shown that the differences in the gut microbiome among cancer patients are linked with different outcomes of these drugs. However, experts have not been able to find out the specific mechanism behind microbiome and immune interaction. Experts have said that patients dealing with advanced-stage cancer are often treated with immunotherapy, which aims at specific proteins on the surface of immune cells, which are known as PD-1 and CTLA-4. As per the data, this treatment works on a subset of cancer patients. Around 50 to 70 percent of patients with cancer do not get any relief from this treatment. Until now, there is no approved treatment for cancer patients who have not been responding to PD-1 immunotherapies. With the new study, experts have tried to find out whether some types of the microbiome can boost the efficiency of PD-1 immunotherapies.
Scientists have taken stool samples of patients who have been responding well to immunotherapy thinking that they might have higher amounts of gut bacteria. Then, they have transferred these samples to patients who have failed this therapy. They have said that as it is hard to find out one or two species of bacteria, which are responsible for beneficial response, they have gone ahead with fecal microbe transplant. Both donors and recipients have been tested for many other diseases to ensure that no contagious agent is transmitted during the transplant. Experts have assessed the transplant 12 weeks after the treatment Patients who have been identified with reduced tumors after the fecal microbe transplant have continued taking pembrolizumab for up to two years. After the transplant, around six out of 15 patients have been identified with reduced tumors or stabilized tumors.
Some of the patients have suffered mild side effects such as fatigue. Patients who have shown a reduction in their tumors or some improvements have been found to have increased numbers of gut bacteria, which have been linked with better responses to immunotherapy. These patients, who have received fecal microbe transplants, have been identified with low levels of adverse immune cells, which are known as myeloid cells. There has been an increase in the levels of memory immune cells in these patients. Experts have seen a drop in levels of key molecules in the immune system, which are linked to resistance in the blood serum of treated patients.