This is a 28-week, single-arm, open-label phase II clinical trial evaluating the combination of Tirzepatide and remote, supervised, tailored resistance exercise training to achieve weight loss in adult survivors of childhood acute lymphoblastic leukemia (ALL) living with obesity or overweight with comorbidity. Primary Objective(s): • To evaluate the effectiveness for weight loss of the combined intervention using once weekly Tirzepatide plus remote, supervised, tailored resistance exercise (three sessions per week) in adult survivors of childhood ALL with obesity or overweight (BMI ≥27 kg/m2) with ≥1 weight-related comorbidity (hypertension, dyslipidemia, obstructive sleep apnea, or cardiovascular disease). The effectiveness will be estimated as the proportion of evaluable participants who achieve at least 5% weight loss from baseline to week 28. The study will target a proportion of participants achieving 5% weight loss of 70% and consider fewer than 40% achieving 5% weight loss as unacceptable. Secondary Objective(s): * Estimate the proportion of participants who adhere to the 28-week combined intervention. Adherence to Tirzepatide will be defined as receiving at least 70% of prescribed doses. Adherence to resistance exercise will be defined as attending at least 50% of prescribed exercise sessions. Adherence to the combined intervention will be considered if participants complete the study and meet both the Tirzepatide and exercise adherence endpoint. The adherence to each component of the intervention will also be reported. * Estimate the average percentage weight loss from week 0 to 28 for participants completing the combined 28-week intervention. The study will target a mean weight reduction of 10% and consider \<5% unacceptable.

Survivors of childhood ALL are at increased risk for obesity and cardiometabolic disease. Tirzepatide is FDA-approved for weight management in adults and results in significant weight loss but may cause lean mass loss. Resistance exercise programs are feasible and effective in this population. This study evaluates the efficacy of combining Tirzepatide with resistance exercise in adult survivors of ALL treated with chemotherapy only and at least 2 years off therapy. The primary objective is to estimate the proportion of participants achieving ≥5% weight loss over 28 weeks. Secondary objectives include adherence to the intervention and changes in body composition, cardiometabolic health, and aging biomarkers.