Here is the design of a clinical trial:

Official Title: Efficacy and Safety of Trifluridine/Tipiracil in Combination With Irinotecan as a Second Line Therapy in Patients With Cholangiocarcinoma

Included conditions:
- Cholangiocarcinoma

Study Armgroups:
- {'label': 'Treatment', 'type': 'EXPERIMENTAL', 'description': 'Combination of Lonsurf® and Irinotecan', 'interventionNames': ['Combination Product: Combination of Lonsurf® and Irinotecan']}

Interventions:
- {'type': 'COMBINATION_PRODUCT', 'name': 'Combination of Lonsurf® and Irinotecan', 'description': 'Trifluridine/Tipiracil (Lonsurf®) and Irinotecan\n\n* Trifluridine/Tipiracil will be administered at a dose of 25 mg/m2 / dose twice daily on days 1-5 followed by a 9-days recovery period from day 6 trough day 14 of each 14-days treatment cycle.\n* Irinotecan will be administered at the same time as Trifluridine/Tipiracil (Lonsurf®) on day 1 of each cycle at a dose of 180 mg/m2 / dose.', 'armGroupLabels': ['Treatment']}

Primary Outcomes:
- {'measure': 'Median progression free survival (PFS)', 'description': 'Median progression free survival (PFS)', 'timeFrame': 'through study completion, an average of 1 year (~4 months intervention + 6 months Follow Up)'}

Please estimate the sample size based on the assumption: 
Exponential failure time, censoring rate of 0.04 per month, and inclusion of 3 dropouts/invalid cases
Sample size calculation
        Sample size consideration for this study is based on the precision of the survival estimate for In total 28 patients (including 3 calculated drop outs and invalid cases) with advanced biliary tract cancers after failure of a gemcitabine based first-line therapy will be enrolled the outcome progression-free survival. The primary endpoint, time till progression-free survival will be analyzed using a non-parametric survival estimate. To this end the method of Turnbull [22] will be used to compute the survival curve. The variance of the survival will be estimated using the Greenwood formula. The log transformation will be used for the calculation of confidence intervals. An exploratory analysis of secondary outcomes will be performed. Overall survival will be analyzed using the KaplanâMeier estimate of survival. For the secondary outcomes, objective response and occurrence of adverse events the proportion of patients with the outcome and confidence intervals using the Wilson method will be calculated [23].