Here is the design of a clinical trial:

Official Title: Effectiveness of the Treatment With Dapagliflozin and Metformin Compared to Metformin Monotherapy for Weight Loss on Diabetic and Prediabetic Patients With Obesity Class III

Included conditions:
- PreDiabetes
- Obesity, Morbid
- Diabetes Mellitus, Type 2

Study Armgroups:
- {'label': 'Metformin/Dapagliflozin', 'type': 'EXPERIMENTAL', 'description': 'Metformin 1,700 mg/day and Dapagliflozin 10 mg/day for a year.', 'interventionNames': ['Drug: Dapagliflozin/Metformin']}
- {'label': 'Metformin', 'type': 'ACTIVE_COMPARATOR', 'description': 'Metformin 1,700 mg/day', 'interventionNames': ['Drug: Metformin']}

Interventions:
- {'type': 'DRUG', 'name': 'Dapagliflozin/Metformin', 'description': 'Two tablets of Metformin 850 mg every 12 hours will be provided in combination with Dapagliflozin 10 mg per day. Each participant will receive diet and exercise intervention according to their BMI and current physical condition.', 'armGroupLabels': ['Metformin/Dapagliflozin'], 'otherNames': ['Group 1']}
- {'type': 'DRUG', 'name': 'Metformin', 'description': 'Two tablets of Metformin 850 mg every 12 hours will be provided. Each participant will receive diet and exercise intervention according to their BMI and current physical condition.', 'armGroupLabels': ['Metformin'], 'otherNames': ['Group 2']}

Primary Outcomes:
- {'measure': 'Change in Weight', 'description': 'Change of 10 percent of initial weight', 'timeFrame': '12 months'}

Please estimate the sample size based on the assumption: 
A power of 80% and an alpha level of 0.05 were used in a two-sided T-test. A 20% dropout rate was also considered.
Sample size
        Weight loss after dapagliflozin treatment has not been previously used as primary outcome in randomized controlled trials (RCT) of patients with prediabetes or diabetes and grade III obesity. Zhang et al. performed a meta-analysis that included seven RCTs evaluating the effect of metformin combined with SGLT2-inhibitors (dapagliflozin 10âmg/day, canagliflozin 300âmg/day, empagliflozin 25âmg/day, or ipragliflozin 300âmg/day) vs. metformin (at doses of 1.5 to 3âg/day) with placebo on HbA1c; fasting plasma glucose; and body weight over 24âweeks, 1âyear, and 2âyears. The total sample was 2847 patients with a mean BMI of 31.7âÂ±â4.9âkg/m2. After a year of treatment, the placeboâmetformin control group showed a reduction in body weight of 1.1âÂ±â3.39âkg, whereas the SGLT-2 inhibitorâmetformin group showed a 3.6âÂ±â4.22âkg reduction with a mean difference of ââ2.6âkg (ââ3.17 to ââ2.03âkg), pâ<â0.00001 [16]. Using these data, we calculated a sample size using a mean difference formula. With a power of 80% (alpha level of 0.05) in a two-sided T-test, the sample size required is 90 patients: 45 patients in the M group and 45 patients in the D/M group. The final sample size required is 108 patients: 54 patients in metformin and 54 patients in the dapagliflozin group, allowing for a 20% dropout rate.