Here is the design of a clinical trial:

Official Title: A Prospective，Multicenter，Randomized Trial of Biweekly Single-dose Actinomycin-D Versus Multi-day Methotrexate Protocol for the Treatment of Low-risk Gestational Trophoblastic Neoplasia

Included conditions:
- Gestational Trophoblastic Tumor
- Gestational Trophoblastic Neoplasia
- Stage I Gestational Trophoblastic Tumor
- Stage II Gestational Trophoblastic Tumor
- Stage III Gestational Trophoblastic Tumor
- Invasive Mole
- Choriocarcinoma

Study Armgroups:
- {'label': 'Arm1-Methotrexate', 'type': 'EXPERIMENTAL', 'description': 'Patients receive methotrexate intramuscularly（50mg） on Days 1, 3, 5, 7 (4 doses per cycle) with Leucovorin (15mg) on Days 2, 4, 6, 8. Repeat every 14 days. Patients continue on treatment until beta HCG titer is below the institutional normal. Patients then receive 2-3 additional consolidation treatment. If the level of hCG become stationary for at least 2 course of single-agent chemotherapy or rise again, the patient will be referred to multi-course chemotherapy. FAV regimen is preferred, or EMA-CO regimen can also be selected if FAV is unavailable.', 'interventionNames': ['Drug: Methotrexate', 'Drug: Leucovorin']}
- {'label': 'Arm 2-Dactinomycin', 'type': 'EXPERIMENTAL', 'description': 'Patients will receive IV pulse actinomycin-D (1.25mg/m2，2mg max dos) every 14 days. Patients continue on treatment until beta HCG titer is below the institutional normal. Patients then receive 2-3 additional consolidation treatment.If the level of hCG become stationary for at least 2 course of single-agent chemotherapy or rise again, the patient will be referred to multi-course chemotherapy. FAV regimen is preferred, or EMA-CO regimen can also be selected if FAV is unavailable.', 'interventionNames': ['Drug: Dactinomycin']}

Interventions:
- {'type': 'DRUG', 'name': 'Methotrexate', 'description': '50mg intramuscularly on Days 1, 3, 5, 7 . Repeat every 14 days', 'armGroupLabels': ['Arm1-Methotrexate'], 'otherNames': ['MTX']}
- {'type': 'DRUG', 'name': 'Leucovorin', 'description': '15mg intramuscularly on Days 2, 4, 6, 8. Repeat every 14 days', 'armGroupLabels': ['Arm1-Methotrexate'], 'otherNames': ['Calcium folinate']}
- {'type': 'DRUG', 'name': 'Dactinomycin', 'description': '1.25mg/m2 (2mg max dose)intravenous every 14 days.', 'armGroupLabels': ['Arm 2-Dactinomycin'], 'otherNames': ['dactinomycin D']}

Primary Outcomes:
- {'measure': 'Completely remission (CR) rate by single-agent', 'description': 'Percentage of participants with complete response by single-agent chemotherapy. A complete response was defined as a normal hCG sustained over 3 weekly measurements.', 'timeFrame': 'from date of treatment begin until the data serum hCG is normal for 3 consecutive weeks by single-agent chemotherapy，assessed up to 8 months'}
- {'measure': 'Overall completely remission rate', 'description': 'Percentage of participants with complete response by single-agent chemotherapy and those by second line multiple-drug chemotherapy after single-agent failure', 'timeFrame': 'from date of treatment begin until the data serum hCG is normal for 3 consecutive weeks by single-agent chemotherapy or multi-agent chemotherapy，assessed up to 12 months'}

Please estimate the sample size based on the assumption: 
Allocation ratio of 1:1, significance level (α) = 0.05, power = 0.8, and 10% drop-out rate.
Sample size calculation
        According to the efficacy of the two chemotherapy regimens reported in previous literature, we estimated that the CR rates of biweekly single-dose Act-D and multiday MTX therapy are 78% and 60%, respectively. Conducting a randomized controlled study with an allocation ratio of 1:1 and considering Î±â=â0.05 and powerâ=â0.8, 103 patients per group are needed. Considering the 10% drop-out rate, each group requires 114 patients (228 patients in total).