Successful Asfotase Alfa Treatment in an Adult Dialysis Patient With Childhood-Onset Hypophosphatasia

Abstract

Hypophosphatasia is an inherited disease characterized by reduced alkaline phosphatase activity, extracellular accumulation of inorganic pyrophosphate, and impaired bone mineralization. Asfotase alfa (AA) is a recombinant human alkaline phosphatase therapy approved for treatment of pediatric-onset hypophosphatasia. Studies show promising outcome in AA-treated children with hypophosphatasia; however, data on adults with pediatric-onset hypophosphatasia are scarce. We report on a 59-year-old woman with childhood- onset hypophosphatasia and a history of multiple fractures and orthopedic procedures. Owing to renal failure (histological diagnosis: focal segmental glomerulosclerosis), hemodialysis was started in 2013. By the end of 2015, the patient was unable to walk, could only stand for 30 seconds, and was completely dependent on help for activities of daily living. After 13 months of AA therapy, the patient showed a dramatic increase in quality of life (increased mobility), reduction in pain medication, and a significant improvement in bone mineralization throughout the skeleton, including consolidation of existing fractures and no occurrence of new fractures. This case report demonstrates a relevant therapeutic success of AA treatment in an adult hemodialysis patient with childhood onset of hypophosphatasia.