Long-Term Follow-Up on a Cohort Temporary Utilization Authorization (ATU) Survey of Patients Treated with Pheburane (Sodium Phenylbutyrate) Taste-Masked Granules

The aim was to describe the status of patients with urea cycle disorders (UCD) at the latest long-term clinical follow-up of treatment with a new taste-masked formulation of sodium phenylbutyrate (NaPB) granules (Pheburane). These patients are a subset of those treated under a cohort temporary utilisation study (ATU) previously reported and now followed for 2 years. From a French cohort temporary utilization authorization (ATU) set up to monitor the use of Pheburane on a named-patient basis in UCD patients in advance of its marketing authorization, a subset of patients were followed up in the long term. Data on demographics, dosing characteristics of NaPB, concomitant medications, adverse events and clinical outcomes were collected at a follow-up visit after 1–2 years of treatment with the drug administered under marketing conditions. This paper reports on the subset of patients who were included in further long-term follow-up at the principal recruiting metabolic reference center involved in the original cohort. No episode of metabolic decompensation was observed over a treatment period ranging from 8 to 30 months with Pheburane, and the range of ammonia and glutamine levels continued to improve and remained within the normal range, thus adding valuable longer-term feedback to the original ATU report. In all, no adverse events were reported with Pheburane treatment. These additional data demonstrate the maintenance of the safety and efficacy of Pheburane over time. The recently developed taste-masked formulation of NaPB granules (Pheburane) improved the quality of life for UCD patients. The present post-marketing report on the use of the product confirms the original observations of improved compliance, efficacy and safety with this taste-masked formulation of NaPB.