Here is the design of a clinical trial:

Official Title: A Phase 2 Randomized, Multi-Centre Study to Investigate the Efficacy and Tolerability of a Second Maintenance Treatment in Patients With Platinum Sensitive Relapsed Epithelial Ovarian Cancer, Who Have Previously Received PARP Inhibitor Maintenance Treatment

Included conditions:
- Ovarian Cancer

Study Armgroups:
- {'label': 'Arm 1 (ceralasertib+olaparib)', 'type': 'EXPERIMENTAL', 'description': 'Participants received ceralasertib 160 mg QD PO on Days 1 to 7 plus olaparib 300 mg BD PO continuous (28 day cycle).', 'interventionNames': ['Drug: Olaparib', 'Drug: Ceralasertib']}
- {'label': 'Arm 2 (olaparib monotherapy)', 'type': 'EXPERIMENTAL', 'description': 'Olaparib 300 mg BD PO daily continuous.', 'interventionNames': ['Drug: Olaparib']}
- {'label': 'Arm 3 (placebo)', 'type': 'EXPERIMENTAL', 'description': 'Placebo to match olaparib BD PO daily continuous.', 'interventionNames': ['Drug: Placebo to match olaparib']}

Interventions:
- {'type': 'DRUG', 'name': 'Olaparib', 'description': 'Olaparib 300 mg BD (2 × 150 mg tablets) continually in the olaparib monotherapy and ceralasertib+olaparib treatment arms.', 'armGroupLabels': ['Arm 1 (ceralasertib+olaparib)', 'Arm 2 (olaparib monotherapy)'], 'otherNames': ['AZD2281']}
- {'type': 'DRUG', 'name': 'Ceralasertib', 'description': 'Ceralasertib 160 mg QD (2 × 80 mg tablets) from Days 1 to 7 (inclusive) of every 28-day cycle.', 'armGroupLabels': ['Arm 1 (ceralasertib+olaparib)'], 'otherNames': ['AZD6738']}
- {'type': 'DRUG', 'name': 'Placebo to match olaparib', 'description': 'Per olaparib', 'armGroupLabels': ['Arm 3 (placebo)']}

Primary Outcomes:
- {'measure': 'Progression free survival (PFS)', 'description': 'To assess the efficacy of maintenance olaparib monotherapy and ceralasertib+olaparib combination therapy compared with placebo.', 'timeFrame': 'To assess from the time of randomization until the date of objective disease progression or death (by any cause in the absence of progression) or approximately up to 2.5 years.'}

Please estimate the sample size based on the assumption: 
The study aims for 83% power to show a statistically significant difference in progression-free survival at the two-sided 4.5% level for olaparib, and 96% power at the two-sided 0.5% level for the olaparib combination arm. The smallest statistically significant HRs at primary analysis are 0.65 for olaparib and 0.55 for the combination arm. An interim futility analysis will be triggered after 25 patients per arm have been assessed for at least 8 weeks. The proportion of patients with non-progressive disease at Week 8 is expected to be 72.6% in the placebo group.
Sample Size
        Approximately 192 patients will be randomized in a 1:1:1 ratio to the three treatment arms.
        Assuming the true treatment effect of olaparib compared with placebo has a HR of 0.53 (this translates to an approximate 3.5-month improvement in median progression-free survival over an assumed 4-month median progression-free survival for placebo), 90 progression-free survival events must be observed for the study to have 83% power to show a statistically significant difference in progression-free survival at the two-sided 4.5% level. The smallest treatment difference that would be statistically significant at the primary analysis is a progression-free survival HR of 0.65.
        Assuming the true treatment effect of the olaparib combination arm (ceralasertib + olaparib) compared with placebo has a HR of 0.38 (this translates to an approximate 6.5-month improvement in median progression-free survival for the combination treatment over an assumed 4-month median progression-free survival for placebo), 90 progression-free survival events must be observed for the study to have 96% power to show a statistically significant difference in progression-free survival at the two-sided 0.5% level. The smallest treatment difference that would be statistically significant at the primary analysis is a progression-free survival HR of 0.55.
        An interim futility analysis will be triggered when approximately 25 patients (75 patients overall) have been recruited into each of the treatment arms and have been assessed for at least 8âweeks. Assuming progression-free survival is exponentially distributed, and the placebo treatment group has a median progression-free survival of 4 months, it is expected that the proportion of patients with non-progressive disease at Week 8 will be 72.6%. If the 80% two-sided exact upper limit of the CI for the proportion of patients with non-progressive disease in the ceralasertib + olaparibâarm or olaparib monotherapy arm is less than 72.6%, with consideration of this analysis in context with the totality of the clinical data (safety and efficacy) available, the Independent Data Monitoring Committee may recommend recruitment cessation.
        An initial overall survival analysis will be performed at the same time as the primary analysis of progression-free survival; a further analysis of overall survival will be performed when the overall survival data are approximately 60% mature (approximately 115 deaths).