Here is the design of a clinical trial:

Official Title: Saracatinib Trial TO Prevent FOP

Included conditions:
- Fibrodysplasia Ossificans Progressiva

Study Armgroups:
- {'label': 'AZD0530', 'type': 'EXPERIMENTAL', 'interventionNames': ['Drug: AZD0530 Difumarate']}
- {'label': 'Placebo/AZD0530', 'type': 'EXPERIMENTAL', 'interventionNames': ['Drug: Matching placebo']}

Interventions:
- {'type': 'DRUG', 'name': 'AZD0530 Difumarate', 'description': 'AZD0530 for the duration of the trial', 'armGroupLabels': ['AZD0530'], 'otherNames': ['Saracatinib']}
- {'type': 'DRUG', 'name': 'Matching placebo', 'description': 'Matching placebo during 6 month RCT, AZD0530 thereafter', 'armGroupLabels': ['Placebo/AZD0530']}

Primary Outcomes:
- {'measure': 'The objective change between the two arms measured in heterotopic bone volume measured by low-dose whole body CT over the initial 6 month RCT', 'timeFrame': 'Baseline, month 6'}

Please estimate the sample size based on the assumption: 
Using a t-test with two-sided alternative, with unequal variances, the trial is 80% powered to detect the minimum clinically meaningful difference with an α = 0.05. An expected drop-out rate of 20% is also considered.
Sample size calculations
          Based on the Natural History Study of FOP, progression of HO in FOP is estimated at 120,000âmm3 on average per 6-month period with a standard deviation of 48,000âmm3 [24]. Expert consensus defines a meaningful decrease in the rate of HO progression as at least 50% reduction in treated vs. control patients, or 60,000âmm3, with a standard deviation of 24,000âmm3. Using this projected impact, using a t-test with two-sided alternative, with unequal variances, a trial with treatment and placebo arms of nÂ =â8 each would be 80% powered to detect this minimum clinically meaningful difference with an Î±â=â0.05 during the initial 6-month study.
          Taking into account an expected drop-out rate of 20%, we calculated the necessary number of participants to be 20 at the start of the study.