Hofmann, C.E., Harmatz, P., Vockley, J. et al. (8 more authors) (2019) Efficacy and safety of asfotase alfa in infants and young children with hypophosphatasia : a phase 2 open-label study. The Journal of Clinical Endocrinology & Metabolism, 104 (7). pp. 2735-2747. ISSN 0021-972X
Abstract
Context
Long-term data on enzyme replacement treatment of hypophosphatasia (HPP) are limited.
Objective
To evaluate efficacy and safety of asfotase alfa in patients aged ≤5 years with HPP followed for up to 6 years.
Design
Phase 2 open-label study (July 2010 to September 2016).
Setting
Twenty-two sites; 12 countries.
Participants
Sixty-nine patients [median (range) age: 16.0 (0.02 to 72) months] with severe HPP and sign/symptom onset before age 6 months.
Intervention
Asfotase alfa 2 mg/kg three times/week or 1 mg/kg six times/week subcutaneously.
Main Outcome Measures
Primary efficacy measure: Radiographic Global Impression of Change (RGI-C) score [−3 (severe worsening) to +3 (complete/near-complete healing)]. Additional outcome measures: respiratory status, growth, and safety. Post hoc analysis: characteristics of radiographic responders vs nonresponders at Year 1 (RGI-C: ≥+2 vs <+2).
Results
During median (minimum, maximum) 2.3 (0.02, 5.8) years of treatment, RGI-C scores improved significantly at Month 6 [+2.0 (−1.7, +3.0)], Year 1 [+2.0 (−2.3, +3.0)], and Last Assessment [+2.3 (−2.7, +3.0); P < 0.0001 all]. Of 24 patients requiring respiratory support at Baseline, 11 (46%) no longer needed support. Height/weight z scores generally increased. Nine patients died (13%). All patients experienced at least one adverse event; pyrexia was most common. Compared with responders [n = 50 (72%)], nonresponders [n = 19 (28%)] had more severe disease at Baseline and a higher rate of neutralizing antibodies (NAbs) at Last Assessment.
Conclusions
Most infants/young children given asfotase alfa showed early radiographic and clinical improvement sustained up to 6 years; radiographic nonresponders had more severe disease and more frequent NAbs at Last Assessment.
Metadata
Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019 Endocrine Society. This article has been published under the terms of the Creative Commons Attribution License (CC BY; https://creativecommons.org/licenses/by/4.0/). | ||||||
Dates: |
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Institution: | The University of Sheffield | ||||||
Academic Units: | The University of Sheffield > Faculty of Medicine, Dentistry and Health (Sheffield) > Department of Oncology (Sheffield) | ||||||
Funding Information: |
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Depositing User: | Symplectic Sheffield | ||||||
Date Deposited: | 30 Aug 2019 13:48 | ||||||
Last Modified: | 25 Jun 2023 21:46 | ||||||
Status: | Published | ||||||
Publisher: | Oxford University Press (on behalf of the Endocrine Society) | ||||||
Refereed: | Yes | ||||||
Identification Number: | https://doi.org/10.1210/jc.2018-02335 | ||||||
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