Gut bacteria research is seeing a resurgence in drug development, including beyond gastrointestinal disorders, with pharmaceutical companies diving into microbiome-focused cancer therapeutic candidates. Experts, however, are taking a cautious stance when it comes to treating melanoma, according to reporting by Reynald Castañeda, Pharma Writer for the Investigative News team at GlobalData, a leading data and analytics company.

Castañeda comments: “There is early data showing manipulating gut flora could enhance efficacy of approved melanoma drugs designed to boost the patient’s own immune system to recognize and kill tumours. So it makes sense several companies have ongoing melanoma trials with microbiome-focused therapeutics.

“However, experts noted it is unclear how susceptible melanoma will be to a microbiome therapy. Also, the fact that melanoma patients are very diverse makes it tough to study microbiome approaches in a clinical trial setting. Every patient will have different bacteria types and ratios.”

4D Pharma, Evelo Biosciences, Seres Therapeutics and Vedanta Biosciences all have clinical-stage microbiome-based assets, according to GlobalData. Each company’s study has slightly differing protocols in terms of which immunotherapy each microbiome approach is being coupled with, as well as the exact treatment regimen being used.

One strategy – employed by Seres and Vedanta – involves using an antibiotic prior to treatment with the experimental microbiome therapy combined with Bristol-Myers Squibb’s Opdivo. Evelo’s trial, on the other hand, skips antibiotic pretreatment but administer EDP1503 for two weeks before combining it with Merck’s Keytruda. 4D’s protocols have MRx0518 administered on the same day as Keytruda.

Castañeda continues: “Experts I spoke to said that trials that leverage a broad-spectrum antibiotic or microbiome monotherapy before coupling with the immunotherapy have some advantages over a straight combination approach. Furthermore, some of the microbiome therapeutics being tested introduce one bacteria type versus a combination of bacterial strains. While the first approach may make it easier to pinpoint what caused efficacy, multiple bacterial types may be more critical for efficacy.”

Evelo’s Phase II EDP1503 and Seres’ Phase Ib SER-401 have data expected in 2H, while Vedanta’s Phase I/II VE800 is anticipated in 2021 and 4D hasn’t disclosed timelines for its Phase I/II MRx0518 trial, according to GlobalData.