For the last decade, we’ve been promised that one day, we’ll be able to mine and modify our microbiomes – the bacteria that live in and on our bodies – to tackle diseases and stay healthy. So far little in the way of practical applications has emerged. This year is different, as attendees at the Human Microbiome Congress in San Diego heard.

A key theme animating the recent conference was the explosion of drugs targeting the microbiome: at least 70 start-ups and institutes are now competing to get the first drugs to market. Pharmaceutical companies are heavily represented – including Bristol-Myers Squibb, Pfizer and Merck – but many other players are supported by private investment and even crowdfunding initiatives. “Collectively, these companies have well over a billion dollars of investment,” says Dirk Gevers at the Janssen Human Microbiome Institute in Spring House, Pennsylvania.

As these potential drugs make their way through clinical trials, early results are promising, but they won’t be on the market for three to five years. However, several of the drugs now in various stages of human trials are already available, or soon will be, thanks to a regulatory loophole that allows them to be sold as cosmetics or food supplements. As long as they make no medical claims before trials conclude, such products are not subject to the same regulations as a medicine.

The people buying them are discovering that they can have dramatic health effects, but some researchers are worried.  “With all the hype about the wonders of microbiome-based medicines, the market is ripe for the picking,” says Eugene Chang at the University of Chicago in Illinois.

Are these products the real deal?

Some of the effects certainly seem to be. One UK-based company, OptiBiotix, sells a range of snack bars meant to control glucose metabolism. Their customers claim to have lost weight and feel less hungry. Last week, the company released results on early research in 50 people whose cholesterol levels had dropped after taking this treatment for 12 weeks.

Later this year, another food supplement, a smoothie mix sachet developed by Microbiome Therapeutics will be available for purchase. The US company recently concluded a small pilot study of the compound, finding that it helped to regulate the blood sugar of volunteers who had diabetes and were pre­diabetic (see chart, below).

The gut microbiome is not the only target. Manipulating the bacteria that cover the skin can also have powerful effects.

In the course of testing its bacterial face spray for acne, San Francisco start-up AOBiome discovered that the spray also brought down volunteers’ blood pressure. To investigate this effect further, the company have begun a separate trial.

The 50,000 customers who have bought the spray as a cosmetic have also reported other effects. Some noticed a reduction in migraines, leading to yet a third trial now in early stages. “We aren’t making any claims, but people are already spraying this stuff everywhere,” says Larry Weiss, the CEO of AOBiome. Still others reported reduced allergies and yeast infections. “These are case reports, and not conclusive,” he says, “but they are an important part of medical discovery.”

Last resort

For some, these products are the only things that have helped their conditions (see “Bacteria in a bottle cured my acne”, right). But it raises the question: is it wise to use these before trials have concluded?

The only insights into this question come from the previous generations of microbial treatments: probiotics and prebiotics backed by little evidence, and, at the other extreme, faecal transplants.

The latter is the only one backed by evidence, but squirting someone else’s faeces inside you isn’t a decision to be taken lightly. In the US, this is only approved to treat Clostridium difficile – a hospital-acquired infection that can strike after antibiotics strip beneficial bacteria from the gut. A faecal transplant from a healthy donor is thought to restore the natural balance, reflected in the 90 per cent cure rate.

However, it’s a blunderbuss approach. Faeces can teem with millions of bacterial strains as well as viruses and fungi. Some of these may be responsible for surprising and sometimes unpleasant consequences of faecal transplants – including obesity. These have led to calls for regulation in countries with fewer restrictions. “I think sooner or later we’re going to start seeing negative consequences of faecal transplants,”says Chang.

This explains why many of the drugs in trials are attempts to create faecal transplants without, well, the faeces. The key to turning this into a standardised and predictable treatment is finding and isolating the specific “healthy”bacteria that should repopulate the gut. Emma Allen-Vercoe at the University of Guelph in Ontario, Canada, is developing a combination of 40 bacterial strains that can be taken as an oral capsule. “We don’t rely on a donor at all,” she says.

Drugs for C. difficile are the first port of call. But for less dire conditions, there are other approaches to manipulating the microbiome. Instead of bacteria, some of the drugs contain ingredients, such as certain kinds of fibre, which nurture the growth of the “friendly”bacteria present in your gut. Pharmaceutical firm Ritter is using this approach to boost the growth of bacteria that ferment lactose, and found this made it easier for lactose-intolerant volunteers to digest dairy foods. The same approach underpins the snack bar and the shake that are now on the market.

Deja vu?

Stripped of the unpredictable and unknown denizens of faecal transplants, then, these products may be less likely to cause similar unintended consequences. But the other risk is that the stuff simply won’t work. This has been a frequent criticism of supermarket probiotics, bacteria-rich capsules and yogurt supported by very little evidence. Because they are marketed as nutraceuticals, their makers evade regulatory scrutiny even as they make vague claims about health. “Proof of these claims is often based on in-house testing which is frequently questionable or flawed,” says Chang.

Although their trials are small, AOBiome’s work is based on a lot of pre-clinical work, Weiss says. He says the company works closely with the Food and Drug Administration, which is also overseeing and guiding similar drugs to the more advanced clinical trials.

The majority of microbiome drugs are not on the market, but their progress is swift.“This field is moving faster than any other field we’ve seen,”says Gevers.

Even self-confessed sceptics like Chang are optimistic that this next wave of microbiome drugs represents the future of medicine. If the products being sold as cosmetics and food supplements clear all the proper hurdles, they will join the new pantheon. 

CASE STUDY

BACTERIA IN A BOTTLE CURED MY ACNE

“I’ve had acne since I was about 9 years old,” says blogger Sabrina Zimmerman, who lives in New York state. “I was bullied and made fun of.”

As she got older, Zimmerman developed cystic acne – which causes painful blemishes that are more deeply embedded in the skin, leaving deep scars.

Zimmerman tried “everything on the market” to get rid of her acne. “I saw dermatologist after dermatologist,” she says. But nothing worked.

Last year, Zimmerman heard about a line of products that contain bacteria from soil. The products, marketed under the name Mother Dirt by a firm called AOBiome, have cleared safety stages to move into more advanced clinical trials for skin disorders, high blood pressure and migraine – but for the time being they can be purchased as cosmetics (see main story).

SPRAY AND HEAL

One of these products delivers bacteria in the form of a mist spray. Since the end of last summer, Zimmerman has been spraying the product all over her body every morning, and spritzing her face before bed. “My skin started to heal,” she says.

After decades of skin problems, Zimmerman’s acne has cleared up. “I still get the occasional hormonal acne, but it’s nothing like the continual breakouts I was having before,” she says.

Zimmerman also uses the spray alongside her deodorant “to keep odour away”. And she has noticed another, more surprising outcome since using the spray all over her body. “I used to have chronic yeast infections,” she says. “After using it in that area, I don’t get them any more.”

While the product is in clinical trials, the company can’t make any claims about its effectiveness. But around 50,000 of the sprays have been sold to date. Some users are reporting other benefits, which have led to new investigatory trials for the drug.