An icky ticket to better health

The United States Food and Drug Administration on April 26 approved the first oral pill derived from human feces.

Seres Therapeutics produces the therapy, which it markets under the Vowst brand. Its intended use is as a preventive measure against recurrent C. diff infections in persons 18 years of age and older. Recurrent C. difficile can cause life-threatening diarrhea and colon inflammation, especially in immunocompromised adults and the elderly. While some medical experts say the new pill offers an attractive alternative to the current status quo, a fecal microbiota transplant, others are more skeptical of its effectiveness.

Microbiota refers to all microorganisms, including bacteria, viruses, fungi and protozoa, living in the human body. During a fecal microbiota transplant (FMT), a patient typically undergoes a colonoscopy to transplant healthy bacteria from a donor’s feces. Beneficial bacteria, initially destroyed by the antibiotics used to treat C. diff, can then trigger an immune response.

With Vowst, instead of undergoing FMT, C. diff. patients can follow a regimen of four capsules daily taken for three consecutive days. “Vowst’s approval is an incredible moment for Seres, and we believe this is just the beginning of what’s possible with microbiome therapeutics,” CEO Eric Shaff said in a conference call with the company. FDA.

Vowst is not the first FMT replacement pill to receive FDA approval. The agency approved Ferring Pharmaceuticals’ Rebyota, a faecal microbiota pill administered rectally in a single dose, in November. Both drugs outperform placebos in studies. Dr. Sahil Khanna, a gastroenterologist at the Mayo Clinic and researcher on clinical trials at Vowst, said it was beneficial for patients to have both options. Khanna noted that some elderly patients with C. diff have trouble swallowing, which makes Rebyota the best choice for them. Others who have aversions to taking anything rectally may prefer Vowst.

Khanna sees Vowst and Rebyota, the first microbiota-based pills to receive FDA clearance, as indicators of improving medicine. “The biggest umbrella is microbiota restoration therapies,” he said. Khanna predicts that microbiota-based therapies will expand to treat medical conditions such as inflammatory bowel disease and multidrug-resistant infections.

While Khanna sees no need to completely move away from FMT procedures, he noted that FMT’s reliance on stool banks is not sustainable. Stool banks are difficult to maintain and access is limited. The non-profit organization OpenBiome, the largest stool bank in the United States, announced plans to phase out its FMT program in February 2022. Commenting on Mayo Clinic’s stool bank, Khanna said: “It’s so cumbersome to manage and maintain that I actually think it’s a welcome thing [to provide alternatives].”

Dr. Alexander Khoruts, a gastroenterologist and director of the Microbiota Therapeutics Program at the University of Minnesota, is less enthusiastic about the new pills. To make the Vowst pill, Seres washes human stool samples with ethanol to kill most bacteria. Only spore-forming Firmicute bacteria capable of surviving the ethanol treatment remain. Khoruts wonders if this purification process removes components of the faecal microbiota that help repair the gut microbiome. He worries about the potential long-term effects of treatment with Vowst versus letting nature take its course with FMT.

As the spore-forming Firmicutes help repair the gut microbiome, Khoruts explained that the rest of the depleted gut bacteria would be replaced with bacteria from the patient’s environment. This is not a good setup for recurrent C. diff patients, who tend to be elderly and are frequently exposed to immunocompromised people due to frequent hospital visits or living in a nursing home. “That’s my safety concern – what happens over a year, a few years, when their microbiome is now replenished?” he said.

Dr Darrell Pardi, a gastroenterologist at the Mayo Clinic, described concerns about Vowst’s effectiveness as “theoretical” in an email to WORLD. Pardi explained that while medical experts don’t know which components of an FMT are needed for efficacy, “the results of the Phase 3 study speak for themselves. The efficacy seen with SER-109 (Vowst) matches what we see with traditional FMT. »

Khoruts noted that Vowst and Rebyota are more expensive than FMT. Vowst’s sticker price is $17,500 per treatment, while Rebyota’s is nearly $9,500. According to the American College of Gastroenterology, FMT costs between $500 and $1,500. He also pointed out that the process of making Rebyota begins with stool donations from paid donors. Khoruts thinks this presents a moral dilemma, as the potential to make money can motivate donors to be dishonest about their medical history to avoid disqualification.

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