A Once-weekly, Repeated Dose, Placebo Controlled, Double Blind, Randomised Cross-over Trial Investigating Safety, Efficacy and Pharmacodynamics of FE 203799 in Patients With Short Bowel Syndrome With Intestinal Failure Requiring Parenteral Support Followed by an Additional Treatment Period in an Open Label Regimen.

This trial is divided into 2 parts. Part A of this trial is a repeated dose, placebo controlled, double blind, randomised cross-over trial investigating safety, efficacy and PD of FE 203799 in 8-10 patients with SBS. Additionally, the plasma concentration of FE 203799 will be assessed for determination of the trough and post-dose concentration in SBS patients. The patients will receive a subcutaneous (SC) dose of 5 mg FE 203799 or placebo once weekly for 4 consecutive weeks, and after a washout period of 6-10 weeks, the alternate treatment will be administered once weekly for 4 consecutive weeks. Safety follow-up assessments will be performed 6-10 weeks after the last dose in each treatment period.

Part B of this trial, treatment period 3, is an open label extension to part A that will test a new dose. Following a washout period of 6-10 weeks after the last dose in treatment period 2, the new dose will be administered once weekly for 4 weeks. Safety follow-up assessments will be performed 4-6 weeks after the last dose in treatment period 3.

The first two administrations of trial drug in each treatment period will be performed at the clinic, while the third and fourth dose can be either self-administered by the patient or administered at the clinic if the patient prefers to travel to the site or other considerations make a site visit preferable.

Prior to each administration of trial drug, liver function parameters will be analysed and assessed. During each treatment period, patients who develop extremely high or persistently elevated liver enzymes following trial drug administration will be discontinued from the trial.

The patients will complete a diary during each treatment period with daily data on parenteral support (PS) usage, oral liquid intake at specific periods, trial drug administrations performed at home, local tolerability and adverse events (AEs).