It sounds like a simple solution to a complicated problem: Find out what kind of obesity someone has based on a one-time genetic saliva test. Then patients and their doctor can get a better idea if antiobesity drugs or other treatments are more likely to work for them.
It’s what Mayo Clinic researchers had in mind when they created four phenotypes of obesity.
Obesity experts not affiliated with the research have some concerns and say independent studies are needed to verify the potential of this strategy.
Dr. Andres J. Acosta
This research could help predict who will respond best to popular antiobesity medications, said Andres Acosta, MD, PhD, cofounder of Phenomix Sciences, the company behind the tests. These medications include glucagonlike peptide–1 (GLP-1) receptor agonists like liraglutide (Saxenda, Victoza) and semaglutide (Ozempic, Wegovy).
“We know that not everyone on a GLP-1 will respond. In reality, about a third of the patients don’t do well with GLP-1s,” said Dr. Acosta, an assistant professor of medicine and researcher in the division of gastroenterology and hepatology at the Mayo Clinic in Rochester, Minn.
Furthest along in development is the “My Phenome Hungry Gut” test for predicting GLP-1 response. People in this Hungry Gut group tend to empty their stomach after a meal faster and are more likely to feel hungry again a short time later, as explained on the company’s website.
A pilot study to test how well it works started in April at three primary care practices. Plans are to expand real-world testing for this and other obesity types later in 2023.
The other obesity categories are:
- “Hungry brain,” where the brain does not recognize signals that the stomach is full
- “Emotional hunger,” where cravings to eat are driven by emotions, anxiety, and negative feelings
- “Slow burn,” where people have a slow metabolism and low energy level
People in these categories might be more likely to benefit from other obesity management strategies, like changes to their diet or placement of an intragastric balloon.
Some things to consider
While applauding their efforts to be more precise in treating people with obesity, not all experts are convinced this saliva test will be the answer. The company’s research might look promising, but verification of results is warranted.
University of Texas Southwestern Medical Center
Dr. Jaime P. Almandoz
“Can we get better outcomes with things like this? Well, that’s the hope,” said Jaime Almandoz, MD, medical director of weight wellness at the University of Texas Southwestern Medical Center, Dallas.
“We still don’t have randomized trials where we’re looking at obesity phenotyping yet,” said Dr. Almandoz, who is also a spokesperson for the Obesity Society, a professional group of clinicians, researchers, educators, and others focused on obesity science, treatment, and prevention.
There is always concern when a diagnostic test is being developed for commercial use, said Daniel Bessesen, MD, a professor of medicine–endocrinology, metabolism, and diabetes at the University of Colorado at Denver, Aurora. “What they’re talking about doing is super important. But this is a company. This is a company that is, I think, selling a product.”
Dr. Michael Camilleri
In an online search, Dr. Bessesen did not find any external studies that showed how well the saliva testing worked. But referring to work by Dr. Acosta and Michael Camilleri, MD, the other cofounder of Phenomix, he said, “I found some papers that they did that I hadn’t read before that are good.”
“These guys are smart guys. And they’ve done a lot of work on [the movement of food through the gut] and how that correlates with obesity and response to some therapies,” said Dr. Bessesen, who is also a spokesperson for the Obesity Society. “So their scientific work does line up with this area.”
Validation of any research is important because the obesity industry has been known for a lot of lose-weight-quick strategies, some with little or no science behind them, he said.
It is also essential, he said, because “anytime you do something commercial in the area of obesity, you have to acknowledge that people with obesity are a vulnerable population. These people face stigma and bias all the time.”