Michael P Whyte1, Cheryl Rockman-Greenberg1, Keiichi Ozono1, Richard Riese1, Scott Moseley1, Agustin Melian1, David D Thompson1, Nicholas Bishop1, Christine Hofmann1. 1. Shriners Hospital for Children (M.P.W.) and Division of Bone and Mineral Diseases at Washington University School of Medicine (M.P.W.), St Louis, Missouri 63110; University of Manitoba and Children's Hospital Research Institute of Manitoba (C.R.-G.), Winnipeg, MB R3T 2N2 Canada; Graduate School of Medicine (K.O.), Osaka University, Osaka, 565-0871 Japan; Alexion Pharmaceuticals, Inc. (R.R., S.M., A.M., D.D.T.), Cheshire, Connecticut 06410; Department of Human Metabolism (N.B.), University of Sheffield, Sheffield, S10 2TN United Kingdom; Sheffield Children's Hospital (N.B.), Sheffield, S10 2TH United Kingdom; University Children's Hospital (C.H.), University of Würzburg, Würzburg, D-97080 Germany.
Abstract
CONTEXT: Hypophosphatasia (HPP) is an inborn error of metabolism that, in its most severe perinatal and infantile forms, results in 50-100% mortality, typically from respiratory complications. OBJECTIVES: Our objective was to better understand the effect of treatment with asfotase alfa, a first-in-class enzyme replacement therapy, on mortality in neonates and infants with severe HPP. DESIGN/ SETTING: Data from patients with the perinatal and infantile forms of HPP in two ongoing, multicenter, multinational, open-label, phase 2 interventional studies of asfotase alfa treatment were compared with data from similar patients from a retrospective natural history study. PATIENTS: Thirty-seven treated patients (median treatment duration, 2.7 years) and 48 historical controls of similar chronological age and HPP characteristics. INTERVENTIONS: Treated patients received asfotase alfa as sc injections either 1 mg/kg six times per week or 2 mg/kg thrice weekly. MAIN OUTCOME MEASURES: Survival, skeletal health quantified radiographically on treatment, and ventilatory status were the main outcome measures for this study. RESULTS: Asfotase alfa was associated with improved survival in treated patients vs historical controls: 95% vs 42% at age 1 year and 84% vs 27% at age 5 years, respectively (P < .0001, Kaplan-Meier log-rank test). Whereas 5% (1/20) of the historical controls who required ventilatory assistance survived, 76% (16/21) of the ventilated and treated patients survived, among whom 75% (12/16) were weaned from ventilatory support. This better respiratory outcome accompanied radiographic improvements in skeletal mineralization and health. CONCLUSIONS: Asfotase alfa mineralizes the HPP skeleton, including the ribs, and improves respiratory function and survival in life-threatening perinatal and infantile HPP.
CONTEXT: Hypophosphatasia (HPP) is an inborn error of metabolism that, in its most severe perinatal and infantile forms, results in 50-100% mortality, typically from respiratory complications. OBJECTIVES: Our objective was to better understand the effect of treatment with asfotase alfa, a first-in-class enzyme replacement therapy, on mortality in neonates and infants with severe HPP. DESIGN/ SETTING: Data from patients with the perinatal and infantile forms of HPP in two ongoing, multicenter, multinational, open-label, phase 2 interventional studies of asfotase alfa treatment were compared with data from similar patients from a retrospective natural history study. PATIENTS: Thirty-seven treated patients (median treatment duration, 2.7 years) and 48 historical controls of similar chronological age and HPP characteristics. INTERVENTIONS: Treated patients received asfotase alfa as sc injections either 1 mg/kg six times per week or 2 mg/kg thrice weekly. MAIN OUTCOME MEASURES: Survival, skeletal health quantified radiographically on treatment, and ventilatory status were the main outcome measures for this study. RESULTS: Asfotase alfa was associated with improved survival in treated patients vs historical controls: 95% vs 42% at age 1 year and 84% vs 27% at age 5 years, respectively (P < .0001, Kaplan-Meier log-rank test). Whereas 5% (1/20) of the historical controls who required ventilatory assistance survived, 76% (16/21) of the ventilated and treated patients survived, among whom 75% (12/16) were weaned from ventilatory support. This better respiratory outcome accompanied radiographic improvements in skeletal mineralization and health. CONCLUSIONS: Asfotase alfa mineralizes the HPP skeleton, including the ribs, and improves respiratory function and survival in life-threatening perinatal and infantile HPP.
Authors: Deborah Wenkert; William H McAlister; Stephen P Coburn; Janice A Zerega; Lawrence M Ryan; Karen L Ericson; Joseph H Hersh; Steven Mumm; Michael P Whyte Journal: J Bone Miner Res Date: 2011-10 Impact factor: 6.741
Authors: Elena Rodriguez; Michael B Bober; Lauren Davey; Arlene Zamora; Annelise B Li Puma; Aaron Chidekel; Thomas H Shaffer Journal: Pediatr Pulmonol Date: 2012-02-10
Authors: M J Weiss; D E Cole; K Ray; M P Whyte; M A Lafferty; R A Mulivor; H Harris Journal: Proc Natl Acad Sci U S A Date: 1988-10 Impact factor: 11.205
Authors: Michael P Whyte; Katherine L Madson; Dawn Phillips; Amy L Reeves; William H McAlister; Amy Yakimoski; Karen E Mack; Kim Hamilton; Kori Kagan; Kenji P Fujita; David D Thompson; Scott Moseley; Tatjana Odrljin; Cheryl Rockman-Greenberg Journal: JCI Insight Date: 2016-06-16