Genetic Liver-Targeted Diseases

Primary HYperoxaluria Observational Study (PHYOS)

Primary HYperoxaluria Observational Study (PHYOS)

 

PHYOS is an international, multicenter, observational study that is collecting data on key biochemical parameters implicated in the pathogenesis of PH1 to better understand the baseline disease state, knowledge that will help guide long-term drug development plans. The study’s primary objective is to measure changes in oxalate, glycolate and other metabolites over a six-month period in patients with PH1. PHYOS investigators are also collecting data on the clinical manifestations of PH1, fluid intake and quality of life.

Investigators are now enrolling patients for the PHYOS study, which will eventually include up to 50 participants at as many as 12 sites worldwide. The study population will consist of two cohorts: Cohort A is enrolling patients age 12 years or older, as individuals in this age group will be considered for upcoming trials of potential PH1 therapeutics. Cohort B will enroll patients aged 6 to 11.9 years, after determination that patients of this age group may be enrolled in PH1 clinical trials.

At the 12th International Workshop for Primary Hyperoxaluria for Professionals, Patients and Families in Tenerife, Spain from July 14-16, 2017, PHYOS investigators reported data from 20 enrolled patients with a median age at screening of 21 years (range 12-61 years). The patients had been diagnosed at a median age of 7 years (range 1-59 years), and 14 patients (74%) had a medical history of renal stones. Overall renal function in these patients had been well preserved. Over the six-month observation period the variability (coefficient of variation) between 24-hour urine measurements of oxalate at different time points was 28%. These data will help the Dicerna clinical team design a clinical study using 24-hour urinary oxalate excretion as a surrogate marker for clinical benefit.