Collaboration to Explore How Gut Bacteria Might Bolster Immunotherapy

Seres Therapeutics and AstraZeneca have established a research collaboration to unravel the mechanisms by which the microbiome – the natural, beneficial community of microbes living in the gut — might enhance the efficacy of cancer immunotherapies.

“Our new collaboration with Seres Therapeutics represents an important opportunity to advance our understanding of the relationship between the microbiome and the immune system’s ability to respond to cancer therapy,” Jean-Charles Soria, MD, PhD, senior vice president, Research & Development Oncology at AstraZeneca, said in a press release.

The human gut microbiome is increasingly recognized as a key factor determining the susceptibility to certain diseases and responses to therapy.

Previous research has shown that the gut microbiome may contribute to the effectiveness of immunotherapy, namely that of checkpoint inhibitors, in cancers such as advanced melanoma. This suggests that people with different microbial composition may respond differently to cancer immunotherapy, and that modifying which microbes reside in the gut may enhance such responses.

“Despite progress in the field of immunotherapy, we are only at the tip of the iceberg. Too many patients are still unable to benefit from existing therapies, so we must continue following the science in pursuit of new and innovative solutions,” Soria said.

Under the collaboration, researchers will investigate patients’ microbiome composition to assess which ones are linked with a better response to certain cancer immunotherapies.

Moreover, Sere’s SER-401, an investigational oral microbiome therapy made up of a mixture of live bacteria, will be tested in combination with AstraZeneca’s cancer immunotherapies. The collection of bacteria in SER-401 is similar to the one seen in patients who responded to cancer immunotherapy.

SER-401 is currently being tested, in combination with Bristol-Myers Squibb’s immune checkpoint inhibitor Opdivo (nivolumab), in a placebo-controlled Phase 1b trial (NCT03817125) with advanced melanoma patients not fit for surgery.

The trial, which is looking for participants, is aiming to include 30 patients to assess SER-401’s safety as a primary goal. Additional objectives include the proportion of patients who respond to treatment, the length of time during and after treatment that a patient lives without disease worsening, and overall survival.

Researchers will also examine whether SER-401’s bacteria are present in the patients’ microbiome.

“We are very pleased to be collaborating with AstraZeneca, a global leader in oncology, to advance the development of potential microbiome-based therapies for cancer,” said Eric Shaff, president and chief executive officer of Seres Therapeutics.

“Through the activities under this collaboration and in our SER-401 Phase 1b clinical study in metastatic melanoma, we hope to meaningfully advance our understanding of the potential for microbiome therapeutics to magnify the impact of cancer immunotherapy,” Shaff added.