The SURMOUNT-Jr study paves the way for the treatment of severe obesity in adolescents with tirzepatide, showing superior results to any existing treatment.
Pediatric obesity is a global public health crisis. In France, approximately 18% of children and adolescents are overweight or obese, with major physical and psychological consequences. The SURMOUNT-Jr study, presented at ObesityWeek 2024, is the first clinical trial evaluating tirzepatide in obese adolescents.
Design of the SURMOUNT-Jr Study
The trial recruited 268 adolescents aged 12 to 17 years with obesity (BMI ≥ 95th percentile for age and sex), randomized to receive tirzepatide (5, 10, or 15 mg) or placebo for 72 weeks. All participants benefited from a lifestyle modification program.
The primary endpoint was the percentage change in BMI at 72 weeks. Secondary endpoints included changes in weight, waist circumference, blood pressure, and metabolic markers.
Impressive Results in Adolescents
The results are remarkable and superior to those observed in adults in terms of BMI reduction:
- Tirzepatide 5 mg: 14.0% BMI reduction (vs +2.4% with placebo)
- Tirzepatide 10 mg: 18.3% BMI reduction
- Tirzepatide 15 mg: 20.3% BMI reduction
In terms of weight, the average loss at the 15 mg dose was approximately 16.1%, comparable to results in adults. However, as adolescents are still growing, the BMI reduction is amplified by the concomitant increase in height.
Safety Profile in Young Patients
The side effect profile in adolescents is generally similar to that in adults, with some specificities:
- Nausea: 25-30% (transient, mainly during titration)
- Diarrhea: 15-20%
- Abdominal pain: 10-15% (slightly more frequent than in adults)
- No safety signal regarding linear growth (height) or bone maturation
- No serious cardiovascular events
The reassuring point is the absence of a negative impact on growth. Adolescents treated with tirzepatide continued to grow normally, a crucial element for the acceptance of this treatment in pediatrics.
Ethical and Practical Implications
Pharmacological treatment of obesity in adolescents raises important ethical questions. Arguments in favor include the severity of the consequences of pediatric obesity (type 2 diabetes, NASH, orthopedic complications, depression) and the frequent failure of lifestyle measures alone. Concerns relate to very long-term effects (adolescents treated today could take tirzepatide for decades), the impact on pubertal development, and the medicalization of childhood.
Current recommendations reserve pharmacological treatment for adolescents with severe obesity (BMI ≥ 35 or ≥ 120% of the 95th percentile) who have not responded to 6 months of intensive behavioral management. The opinion of a multidisciplinary team (pediatrician, endocrinologist, psychologist, dietitian) is essential.
Regular follow-up is even more crucial in adolescents than in adults. The MounjaGO application allows for daily monitoring easily accessible to young patients and their parents.
FAQ: Tirzepatide in Adolescents
At what age can tirzepatide be started?
The SURMOUNT-Jr study included adolescents aged 12 to 17 years. Any eventual authorization would likely concern this age group. No data currently exist for children under 12 years of age.
Does tirzepatide affect adolescent growth?
No, SURMOUNT-Jr data show no negative impact on linear growth or bone maturation. Treated adolescents continued to grow normally.
Is Mounjaro already available for adolescents in France?
Not yet. Authorization for adolescents requires specific evaluation by the EMA and HAS. The application for indication extension is ongoing and could be finalized in 2026-2027.