Table 1.

MAA criteria for maintaining treatment

Clinical criteria Treatment-naïve patients: criteria following the first year of treatment  • Improvement in 6MWT distance or the timed 25-foot (7.6 m) walk (T25FW) of ≥ 10% over baselinea or stabilisation after 10% improvementb  • Improvement in FVC or FEV1 of ≥ 5% over baseline or stabilisation after 1 year  • Decline in LVEF of < 10% from baseline  • Decline of uKS of ≥ 20% from baseline (and stabilised)

Ex-trial patients or patients receiving treatment for over 12 months  • 6MWT or T25FW remains ≥ 5% above the baseline value at the start of treatment  • FVC and FEV1 remain ≥ 2% above the baseline value at the start of treatment  • uKS levels remain reduced ≥ 20% from baseline  • Decline in LVEF of < 10% from baseline

PRO criteria (same for treatment-naïve and ex-trial patients):  • No adverse change in numerical valuec of two out of three of the following:   • EQ-5D-5L score OR MPS-HAQ Caregiver Burden score   • Beck Depression Score (≥ 13 years)   • APPT/BPI pain severity score (depending on age)

6MWT 6-min walk test, APPT adolescent pediatric pain tool, BPI Brief Pain Inventory, EQ-5D-5L EuroQol 5 dimensions, 5 levels, FEV₁ forced expiratory volume in 1 s, FVC forced vital capacity, LVEF left ventricular ejection fraction, MPS-HAQ MPS Health Assessment Questionnaire, PRO patient-reported outcome, uKS urinary keratan sulphate

^aAs measured at the annual assessment

^b6MWT distance initially increased by 10% or more versus baseline, and then remained at least 5% above the baseline value at the start of treatment

^cThe MAA agreement did not specify how adverse change was defined for each instrument. Patients were assessed on a case-by-case basis where no adverse change means absolute scores remain stable (within the same category) or improve