Therapeutic Use of Oral Sodium Phosphate (Phosribbon® Combination Granules) in Hereditary Hypophosphatemic Rickets

Oral sodium phosphate formulations indicated for hypophosphatemia are commercially available worldwide. In Japan, however, many medical institutes have used hospital dispensary or foreign over-the-counter formulations because no such medication with an indication covered by the health insurance system is domestically available. To address this problem, we initiated the development of Phosribbon(®). The present study evaluated the efficacy and safety of Phosribbon(®) in 16 patients with hereditary hypophosphatemic rickets. The optimal dosage and an administration pattern were also investigated. Administration of the agent resulted in an increase in the level of serum phosphorus in all patients, which implied that the employed dosage was appropriate. The dosage and administration pattern were adjusted based on comprehensive considerations, including changes in clinical laboratory values such as serum phosphorus, alkaline phosphatase and intact PTH, the dosage of a concomitantly administered activated vitamin D formulation and characteristics of individual patients. Adverse drug reactions were observed in 2 patients, neither of which were serious or necessitated therapy dose reduction or discontinuation. We conclude that Phosribbon(®) is a safe and effective treatment for patients with hypophosphatemic rickets and that dose adjustment in this therapy can be guided by the results of regular clinical examination and renal ultrasonography. (ClinicalTrials.gov Identifier: NCT01237288).