AstraZeneca taps microbiome specialist Seres for I-O support

AstraZeneca SVP Jean-Charles Soria. (ESMO)

AstraZeneca has teamed up with Seres Therapeutics to explore whether microbiome therapeutics can increase the efficacy of cancer immunotherapies. The deal will see AstraZeneca pay $20 million to collaborate with Seres and test SER-401 in combination with its oncology assets.

Seres firmed up its interest in using microbiome therapeutics in immuno-oncology when it teamed up with the MD Anderson Cancer Center and the Parker Institute for Cancer Immunotherapy to test SER-401 in combination with a checkpoint inhibitor. The collaboration was underpinned by evidence that the gut microbiome influences how patients with melanoma respond to anti-PD-1 drugs.

In AstraZeneca, Seres has found a partner willing to support further explorations of that idea. Seres will receive $20 million from AstraZeneca in three installments over the next two years, plus money to cover research costs it incurs in the course of the collaboration. Shares in Seres rose 25% following news of the deal. 

In return, Seres will work with AstraZeneca to assess the use of the microbiome to predict whether a patient will respond to cancer immunotherapies. The aforementioned evidence of a link between the composition of the microbiome and responses to checkpoint inhibitors suggests it may be possible to identify responders based on gut bacteria.  

The other strand of the collaboration could result in more patients having microbiomes that correlate to responsiveness to checkpoint inhibitors. Seres developed SER-401 by analyzing bacteria found in immunotherapy responders and creating a cocktail that mirrors the microbiome signature seen in these patients. 

Now, Seres has cleared AstraZeneca to test SER-401 in combination with other cancer treatments. Through these tests, AstraZeneca could gain an edge on the immuno-oncology leaders by rendering more people responsive to its drugs. 

“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,” AstraZeneca SVP Jean-Charles Soria, M.D., Ph.D., said in a statement. 

AstraZeneca isn’t the first company to spot the opportunity, though. In 2016, Bristol-Myers struck a deal with Enterome to discover microbiome-derived targets and drugs that could support its cancer drugs. 

News of the AstraZeneca collaboration comes one week after Seres disclosed the initiation of a phase 1b study of SER-401 in patients with metastatic melanoma. The study, which will be run with MD Anderson and the Parker Institute, will assess the effect of giving SER-401 in combination with Bristol-Myers Squibb’s anti-PD-1 checkpoint inhibitor Opdivo.

Investigators will pretreat all 30 patients enrolled in the trial with the antibiotic vancomycin for four days “to prime the gut microbiome for engraftment of the oral microbiome study intervention.” Beyond that, two-thirds of the patients will receive SER-401 and Opdivo, with the remainder taking a placebo on top of the checkpoint inhibitor.

The trial has a safety-focused primary endpoint, but Seres is also looking to generate evidence that the bacteria in SER-401 take root in patients and affect key efficacy measures, including response and survival rates.