A team of Canadian scientists is exploring whether human poo transplants can be used to treat one of the deadliest forms of skin cancer.
Traditionally, melanoma is treated with immunotherapy drugs, which stimulate the patient's immune system to attack and destroy cancer cells.
But while these drugs can significantly improve survival outcomes in those with melanoma, they are only effective in 40-50% of patients.
Scientists believe that the human microbiome - the diverse collection of microbes in our body - may play a vital role in whether or not a patient responds.
"The gut microbiome helps establish immunity from an early age. It makes sense that a healthy gut could improve response to immunotherapy," explains Dr. Jeremy Burton, a Lawson Scientist who specialises in human microbiome research.
"This led us to consider the potential of fecal transplants."
Fecal transplants involve collecting a stool from a healthy donor, preparing it in a lab and transplanting it to the patient.
The goal is to transplant the donor's microbiome so that healthy bacteria will colonise in the patient's gut, helping their body respond to the immunotherapy drugs.
Twenty melanoma patients from the London Regional Cancer Program at the London Health Sciences Centre in Ontario will take part in the first clinical trial of the new treatment.
The fecal transplant will consist of taking a number of specially-prepared oral capsules, which the patient will swallow before receiving immunotherapy as normal.
Patients will be assessed over time for any changes to their cancer, microbiome, immune system and overall health.
The primary goal of the study is to evaluate safety of the novel treatment combination, but researchers will also evaluate patient outcomes.
"Melanoma is the least common skin cancer but it is the deadliest and rates are going up," says Dr. John Lenehan, Associate Scientist at Lawson and Oncologist at LHSC.
"Anti-PD1 immunotherapy drugs can be extremely effective but we want to help more patients respond. That's our goal."
While the team is studying the combination of fecal transplants and immunotherapy for melanoma, they see potential for other cancers as well.
"We're one of the first in the world to study fecal transplants in cancer patients," said Dr. Saman Maleki, a Lawson Associate Scientist who specialises in cancer immunology.
"This study is as cutting-edge as it gets with potential applications for multiple disease sites.
"With experts in microbiology, infectious disease, cancer and immunology, our institute is well-positioned to carry this forward."
Fecal transplants have already been used to treat patients with recurrent C. diff - the diarrhoea-causing superbug that is common in hospital - saving countless lives.
The researchers are now starting to see its potential for the treatment of other diseases including non-alcoholic fatty liver disease, multiple sclerosis (MS) and cancer treatment toxicity.