A few months ago I commented in an article on the use of fecal transplants for the treatment of infections caused by the bacteria Clostridioides difficile (formerly known as Clostridium difficile). Although stool transplants are recognized as an effective therapy, not all are advantages.
One of the problems is that the droppings must come from a healthy donor. Another is that they must be analyzed and processed to ensure that they do not contain potentially pathogenic microorganisms. And as if that were not enough, each donor has its own microbiota, so the variability is enormous.
The treatment of infections C.difficile, which cause diarrhea and colitis, would be greatly simplified if doctors had a bacterial preparation with the desired therapeutic potential and its safety and efficacy were guaranteed. That is, to obtain a biopharmaceutical designed to displace the pathogenic microorganism.
A preparation of spores
One of the first pharmaceutical companies to explore this idea was the company Seres Therapeutics. In 2015, he managed to get the multinational Nestlé to invest 65 million dollars for the development of its products based on probiotics.
Among the most promising was a product called SER-109. It consisted of a preparation of spores obtained from fifty bacterial species isolated from feces of healthy carriers. The spore preparation is administered orally.
The results were so good that in July 2015 the company went public. On the first trading day it was valued at 139 million dollars, and in the following days it continued to rise.
However, on July 29, 2016, the company had a setback. The results of the phase 2 clinical trial of SER-109 were published and they were not as good as expected. In just one day the shares plummeted 70%, which meant the loss of 1 billion dollars in the company’s valuation.
suspended bacteria
Seres Therapeuthics was the first company to conduct a clinical trial of this type of medication, but it was not the only one. Another firm that began to investigate in this field was Rebiotix, a small start up from Minnesota.
In your case, the strategy is somewhat different. Instead of a spore preparation, what they use is a suspension of bacteria isolated from human feces of healthy carriers. The bacterial suspension is administered to patients through a 150-milliliter enema.
Early results were also promising, and in 2014 he raised $25 million to continue his trials. In April 2018 Rebiotix was acquired by the Swiss pharmaceutical company Ferring.
The Swiss company had enough capital to cover the costs of the Phase 3 clinical trial, the final stage before a drug can be approved for sale. In May 2021, they presented the positive results of this phase and requested evaluation from the FDA (the US drug agency).
On November 30, by a vote of 13 to 4, the FDA gave its approval to the medicine called Rebyota for the treatment of recurrent infections due to C.difficile.
And what happened to Seres Therapeutics? She was the first to leave but she will be the second to arrive. After redesigning her procedures, she was able to move forward with clinical trials (Nestlé put another $175 million on the table). In January 2022, they presented the positive results of phase 3 of the clinical trial of their product. It is expected that by April 2023 they will have obtained permission from the FDA. In other words, not one, but two treatments will soon be available to treat recurrent infections due to C.difficile.
A new therapeutic field
With the appearance of this type of biopharmaceuticals, we should start talking about microbiota replacement therapy instead of fecal transplants. Rebyota is the first drug of its kind, but it probably won’t be the last.
Additionally, both Ferring and Seres Therapeutics believe that microbiota replacement can be used in the treatment of other conditions. For example, ulcerative colitis, recurrent urinary infections by microorganisms resistant to antibiotics or some metabolic disorders. And who knows, maybe in the future they will also be used as rejuvenation therapies.
