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In big year for microbiome drugs, a small biotech sets the bar

A small Massachusetts biotech has released new data which support the idea that boosting healthy bacteria in people’s bodies can help them recover from sometimes deadly illnesses.

The data come from a study of just over 200 patients who were battling recurrent infections from Clostridioides difficile, or C. diff, a bacterium that invades the intestines and can cause diarrhea or, in severe cases, life-threatening colon inflammation. Eight weeks in, the study showed a 62% cure rate for patients treated with just standard-of-care antibiotics, but a 75% cure rate for those who got antibiotics as well as an experimental drug from Finch Therapeutics.

This difference in cure rates was large enough to declare the drug, called CP101, successful on the study’s main goal. Finch expects to eventually run another large trial to confirm the results, and will use the two datasets together to support a submission for approval.

An approval would be a milestone not only for Finch, which launched in 2017 with just under $6 million in funding, but also a larger field of research that focuses on the ways human health is affected by the microbes living inside our bodies. Scientists have theorized this so-called microbiome may offer a path to treating a wide range of diseases, from inflammatory bowel to Alzheimer’s.

“For a long time, we didn’t have the technology to understand the complexity of these [microbe] communities and how they might impact our health,” Finch CEO Mark Smith told BioPharma Dive. But research recently hit a turning point, providing drug companies with a better understanding of the microbiome and the tools needed to “rewire it in a way that improves patient outcomes by restoring the complexity of this community,” according to Smith.

These advances didn’t come without setbacks, however. In July 2016, one of the field’s pioneering companies, Seres Therapeutics, announced that its leading experimental therapy had failed in a mid-stage clinical trial — an outcome that seemed to cool big pharma’s interest in the microbiome.

Deep-pocketed drug developers have slowly started to come back around, with Roche, Takeda, AstraZeneca and Gilead all teaming up with small, specialized biotechs over the past few years to do microbiome research. If successful, their work would fill big gaps in therapeutic options; currently, the main treatment for a sick microbiome is a fecal transplant, an invasive procedure that has triggered safety concerns at the Food and Drug Administration.

This year offers another potential turning point as Finch, Seres and privately owned Rebiotix report pivotal data for their experimental microbiome medicines targeting C. diff.

Rebiotix, acquired by Swiss drugmaker Ferring Pharmaceuticals in 2018, was the first to do so, announcing in May “positive preliminary results” from a late-stage study testing its lead drug in patients with C. diff infections. The company didn’t provide any details — or data — but said full results would be presented in the back half of the year.

Seres, meanwhile, expects its study to read out sometime in mid-2020.

The data from Rebiotix and Seres should help contextualize Finch’s. Until then, both the company and the microbiome research field are left to draw their own conclusions on how compelling the early results are.

To Smith, the 13% difference in cure rates between the active and comparator arms shows that CP101 is “better than the existing treatment options available for these patients.”

Finch’s Chief Medical Officer Zain Kassam said it would also matter to doctors treating C. diff infections, since there’s not many options to layer on top of standard-of-care antibiotics.

Joe Petrosino, a director at the Baylor College of Medicine’s Center for Metagenomics and Microbiome Research, described the difference in cure rates as “modest,” but also a “step in the right direction” as the field expands beyond fecal transplants. Finch’s and Seres’ drugs are taken orally, while Rebiotix’s is an enema. All are donor-derived therapies composed of gut bacteria.

Yet the results are made more encouraging, according to Petrosino, by the 51 sites Finch used to collect data.

“The fact that they still saw this signal, even through all the noise that you sometimes get when you have a highly spread-out clinical trial, I think is actually a good sign,” he said, adding that the trial’s design should make it easy to scale up for any large, confirmatory study.

Petrosino reviewed the data at BioPharma Dive’s request on the condition he not share the results.

Like other trials, Finch’s mid-stage study enrolled patients whose infections had persisted after multiple rounds of antibiotics. But it also enrolled those who had failed only one treatment prior — and it’s this population in which Smith sees a drug like CP101 as particularly beneficial, since the microbiome takes damage after each line of antibiotic therapy.