BackgroundAspiration sclerotherapy is an effective therapeutic option for large symptomatic hepatic cysts. However, incomplete cyst reduction following aspiration sclerotherapy is frequently reported. Strong post-procedural cyst fluid secretion by cholangiocytes, which line the epithelium of the hepatic cyst, seems to be associated with lower reduction rates. Previous studies showed that somatostatin analogues curtail hepatic cyst fluid production. This trial will evaluate the effect of aspiration sclerotherapy combined with the somatostatin analogue pasireotide on cyst reduction. By combining treatment modalities we aim to improve cyst reduction leading to greater symptomatic relief and reduced rates of cyst recurrence.Methods/DesignThis single center, randomized, double-blind, placebo-controlled clinical trial evaluates the additional effect of pasireotide when combined with aspiration sclerotherapy in patients with a large (>5 cm) symptomatic hepatic cyst. A total of 34 participants will be randomized in a 1:1 ratio. In the active arm, patients will receive pasireotide (long-acting release, 60 mg injection) two weeks prior to and two weeks following aspiration sclerotherapy. Patients in the control arm will receive placebo injections at corresponding intervals. The primary outcome is proportional cyst diameter reduction four weeks after aspiration sclerotherapy compared to baseline measurements, obtained by ultrasonography. As secondary outcomes, proportional volume reduction, recurrence, symptomatic relief and improvement of health-related quality of life will be assessed. Furthermore, safety and tolerability of the combination of pasireotide and aspiration sclerotherapy will be evaluated.DiscussionThis trial aims to improve efficacy of aspiration sclerotherapy by a combined approach of two treatment modalities. We hypothesize that pasireotide will decrease fluid re-accumulation after aspiration sclerotherapy, leading to effective hepatic cyst reduction and symptomatic relief.Trials registrationThis trial is registered with ClinicalTrials.gov (identifier: NCT02048319; registered on 6 January 2014) and EudraCT (identifier: 2013-003168-29; registered on 16 August 2013).