Genetic Test Predicts Semaglutide Response in Post-Bariatric Surgery Patients
Key Insights
A novel genetic biomarker test successfully predicted patient response to semaglutide treatment following bariatric surgery, with 95% of "hungry gut positive" patients achieving at least 5% weight loss at 6 months.
The MyPhenome test uses machine learning to analyze 41 genes from the gut-adipose-brain pathway, creating a calories-to-satiation gene risk score that stratifies patients into response categories.
Patients with hungry gut positive scores achieved significantly greater weight loss (-10%) compared to hungry gut negative patients (-5.2%) at 6 months, with a p-value of 0.05.
A machine learning-based genetic test has demonstrated the ability to predict patient response to semaglutide treatment following bariatric surgery, according to research presented at ObesityWeek. The MyPhenome test, developed by Phenomix Sciences (search), represents a significant advancement in precision medicine for obesity management in post-surgical patients.
Novel Genetic Approach to Treatment Prediction
The MyPhenome test utilizes a gene risk score based on 41 expert-guided candidate genes from the gut-adipose-brain pathway that identify peripheral signals related to GLP-1 (search), appetite, and satiation. "Our lab has developed a gene risk score for satiation [that works] with 41 expert-guided candidate genes from the gut-adipose-brain pathway that identified peripheral signals from the GLP-1, appetite and satiation," said Jose C. Villamarin, MD, research fellow at Mayo Clinic.
The test functions as a machine learning gene risk score that predicts high calories to satiation, which in turn predicts obesity and treatment outcomes. This approach moves beyond traditional metrics to examine the underlying biological mechanisms governing appetite regulation.
Clinical Study Results
Researchers analyzed data from the Mayo Clinic Biobank of 52,619 patients, identifying 68 adults with obesity who had undergone bariatric surgery and subsequently received semaglutide treatment. The study population was 83.8% women with a mean age of 49.5 years and baseline BMI of 38.4 kg/m². Participants had undergone either Roux-en-Y gastric bypass (n = 51) or sleeve gastrectomy (n = 17) and received semaglutide doses ranging from 0.25 mg to 2.4 mg.
Using genetic data, researchers stratified participants into two groups based on their calories to satiation gene risk score: "hungry gut positive" (score < 0.5, n = 56) and "hungry gut negative" (score ≥ 0.5, n = 12).
Significant Weight Loss Differences
The primary outcome measured percentage of total body weight loss at 6 months, with secondary outcomes at 2 and 4 months. Results showed progressive divergence between the two groups over time:
At 2 months, total body weight loss was -3.7% in the hungry gut positive group compared to -3% in the hungry gut negative group. By 4 months, the difference widened to -6.4% versus -4.8% respectively (P = .39). At the 6-month primary endpoint, hungry gut positive patients achieved -10% weight loss compared to -5.2% in the hungry gut negative group (P = .05).
Response Rate Analysis
The study revealed substantial differences in response rates between genetic groups. At 6 months, 95% of hungry gut positive patients achieved at least 5% body weight loss compared to 60% of hungry gut negative patients. For clinically significant weight loss of at least 10%, 35% of hungry gut positive patients reached this threshold versus only 10% of hungry gut negative patients. Similarly, 23% of hungry gut positive patients achieved at least 15% weight loss compared to 10% of hungry gut negative patients.
Test Performance Characteristics
The MyPhenome test demonstrated an area under the curve of 0.63 (95% CI, 0.47-0.78) when predicting semaglutide responders, defined as achieving at least 10% body weight reduction at 6 months. The test showed high sensitivity at 96% and strong negative predictive value at 90%, though specificity was lower at 31%. The positive predictive value was 53%.
Broader Clinical Implications
"Our biomarker identifies the best responders to semaglutide in post-Roux-en-Y gastric bypass bariatric patients," Villamarin stated. "The genetic integrity of the homeostatic food intake regulation pathway needs to be intact to optimize the response to a GLP-1 (search) receptor agonist, and our results support a novel approach for precision medicine for obesity."
Additional research presented at ObesityWeek demonstrated that the MyPhenome test also predicted GLP-1 (search) therapy response across racially and ethnically diverse populations, suggesting broad clinical applicability.
Clinical Implementation
The genetic test technology has been licensed to Phenomix Sciences (search) and is currently implemented in over 300 clinics across the United States. The test requires only a simple blood or saliva sample, making it accessible for routine clinical use.
This development addresses a critical need in post-bariatric surgery care, where weight regain remains a significant challenge. By identifying patients most likely to respond to semaglutide treatment based on their genetic profile, clinicians can make more informed treatment decisions and potentially improve outcomes while optimizing healthcare resources.