The numbers of participants who experienced Adverse Events (AEs), Serious Adverse Events (SAEs), treatment-related AEs, and Infusion Associated Reactions (IARs). Summary is based on treatment-emergent AEs (TEAEs), defined as AEs that occurred following the initiation of study treatment with alglucosidase alfa.

Participants with long-term exposure to alglucosidase alfa (those from the Alglucosidase Alfa/Alglucosidase Alfa treatment group) are included. Time frames are stated from the start of the double-blind study AGLU02704 (NCT00158600).

The safety population includes all participants randomized to alglucosidase alfa treatment in AGLU02704 (NCT00158600) who received at least one infusion of alglucosidase alfa.

Quantitative muscle testing (QMT) is a standardized system to measure muscle force production during maximal voluntary isometric contraction. QMT data were collected directly from sensors into laptop computers. Predicted normal values for QMT are based on a formula using sex, age and body mass index of a person, and are an estimate of healthy muscle force. Percent of predicted QMT = (observed value)/(predicted value) * 100%. The QMT Leg Score is the average of the bilateral means for percent predicted knee flexors and extensors. A value of 100% indicates 'normal' muscle strength.

Intent-to-treat population

Six-Minute Walk Test (6MWT) measures the distance walked (in meters) in 6 minutes. A longer distance indicates greater endurance. Time frames are stated from the start of the double-blind study AGLU02704 (NCT00158600).

Intent-to-treat population.

Six-Minute Walk Test (6MWT) measures the distance walked (in meters) in 6 minutes. A longer distance indicates greater endurance. Time frames are stated from the start of the double-blind study AGLU02704 (NCT00158600). Change is calculated as the value minus the baseline value.

Intent-to-treat population of participants who had both baseline (Week 0) and Week 104 data.

Quantitative muscle testing (QMT) is a standardized system to measure muscle force production during maximal voluntary isometric contraction. QMT data were collected directly from sensors into laptop computers. Predicted normal values for QMT are based on a formula using sex, age and body mass index of a person, and are an estimate of healthy muscle force. Percent of predicted QMT = (observed value)/(predicted value) * 100%. The QMT Leg Score is the average of the bilateral means for percent predicted knee flexors and extensors. A value of 100% indicates 'normal' muscle strength.

Intent-to-treat population of participants who had both baseline (Week 0) and Week 104 data.

Forced vital capacity (FVC) is a standard pulmonary function test used to quantify respiratory muscle weakness. FVC is the volume of air that can forcibly be blown out after full inspiration in the upright position, measured in liters. Predicted forced vital capacity is based on a formula using sex, age and height of a person, and is an estimate of healthy lung capacity. Percent of predicted FVC = (observed value)/(predicted value) * 100%. Time frames are stated from the start of the double-blind study AGLU02704 (NCT00158600).

Intent-to-treat population

Forced vital capacity (FVC) is a standard pulmonary function test used to quantify respiratory muscle weakness. FVC is the volume of air that can forcibly be blown out after full inspiration in the upright position, measured in liters. Predicted forced vital capacity is based on a formula using sex, age and height of a person, and is an estimate of healthy lung capacity. Percent of predicted FVC = (observed value)/(predicted value) * 100%. Time frames are stated from the start of the double-blind study AGLU02704 (NCT00158600). Change is calculated as the value minus the baseline value.

Intent-to-treat population of participants who had both baseline (Week 0) and Week 104 data.

The Medical Outcomes Study Short Form (MOS SF)-36 questionnaire consists of 36 items grouped into 8 domains designed to assess generic health-related quality of life in healthy and ill adult populations. Physical Component Score reports the four domains of physical functioning, role-physical, bodily pain, and general health and are standardized as Z-scores (scale of 0-100). Higher scores are associated with better quality of life. Time frames are stated from the start of the double-blind study AGLU02704 (NCT00158600).

Intent-to-treat population of participants with valid baseline (Week 0) PCS surveys.

The Medical Outcomes Study Short Form (MOS SF)-36 questionnaire consists of 36 items grouped into 8 domains designed to assess generic health-related quality of life in healthy and ill adult populations. Physical Component Score reports the four domains of physical functioning, role-physical, bodily pain, and general health and is standardized as Z-scores (scale of 0-100). Higher scores are associated with better quality of life. Change is calculated as the value minus the baseline value. Time frames are stated from the start of the double-blind study AGLU02704 (NCT00158600).

Intent-to-treat population of participants who had valid baseline (Week 0) and Week 104 data.