Protara Therapeutics, Inc. announced the completion of a retrospective prevalence study designed to enhance understanding of the incidence of intestinal failure associated liver disease (IFALD) in patients dependent on parenteral nutrition (PN). The study found that approximately 30% of patients who are dependent on PN have cholestasis, a hallmark pathology of IFALD, despite the use of current medical management in these patients. The Company is currently developing intravenous (IV) Choline Chloride, an investigational phospholipid substrate replacement therapy, for the treatment of patients receiving PN who have IFALD. In order to further characterize the prevalence and needs of IFALD patients dependent on PN, the Company recently initiated a prospective, multi-center, cross-sectional observational study that will assess the prevalence of choline deficiency, as well as cholestasis and steatosis, in approximately 300 patients dependent on PN. The Company expects to use the results from the completed retrospective study and ongoing prospective study to inform next steps for its IV Choline Chloride development program. As previously announced, the Company held a positive end of Phase 2 meeting with the U.S. Food and Drug Administration (FDA) and received feedback on the design of studies necessary to complete the registration package for IV Choline Chloride for the treatment of IFALD, including a Phase 1 pharmacokinetic study and a Phase 3 placebo-controlled study. The retrospective, observational study was conducted in partnership with a large home health organization and examined data from 468 patients dependent on PN for six months or more. The primary endpoint of the study was to identify the proportion of patients dependent on PN with suspected liver disease defined as serum alkaline phosphatase (ALP) levels greater than 1.5 times the upper limit of normal (ULN). The study evaluated ALP levels from baseline up to 36 months to determine if there is a progressive component to cholestasis in IFALD and the degree to which medical management affected ALP levels. ALP is an established biomarker for cholestasis and a clinically meaningful indicator of IFALD severity and progression. Prolonged elevation of ALP is indicative of ongoing hepatocellular injury.