Trial Outcomes & Findings for A Study to Assess the Long-term Safety and Efficacy of ATB200/AT2221 in Adult Subjects With Late-Onset Pompe Disease (LOPD) (NCT NCT04138277)

NCT ID: NCT04138277

Last Updated: 2026-03-05

Results Overview

Number of subjects with TEAE, TESAE, and TEAE leading to discontinuation during this long-term extension study

Recruitment status

COMPLETED

Study phase

PHASE3

Target enrollment

119 participants

Primary outcome timeframe

Entire extension study (mean = 40.5 months on treatment)

Results posted on

2026-03-05

Participant Flow

Participant milestones

Participant milestones
Measure	Treatment Continued Group Participants who received ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in the feeder study who continued on that dose in this long-term extension	Treatment Switched Group Participants who received alglucosidase alfa/placebo in the feeder study who were switched to ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in this long-term extension
Pretreatment STARTED	82	37
Pretreatment COMPLETED	81	37
Pretreatment NOT COMPLETED	1	0
Treatment STARTED	81	37
Treatment COMPLETED	58	30
Treatment NOT COMPLETED	23	7

Reasons for withdrawal

Reasons for withdrawal
Measure	Treatment Continued Group Participants who received ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in the feeder study who continued on that dose in this long-term extension	Treatment Switched Group Participants who received alglucosidase alfa/placebo in the feeder study who were switched to ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in this long-term extension
Pretreatment Withdrawal by Subject	1	0
Treatment Adverse Event	6	2
Treatment Lost to Follow-up	1	0
Treatment Pregnancy	3	0
Treatment COVID-19 pandemic	1	0
Treatment Withdrawal by Subject	9	3
Treatment Sponsor decision	1	0
Treatment Physician Decision	1	0
Treatment Worsening of condition	1	2

Baseline Characteristics

A Study to Assess the Long-term Safety and Efficacy of ATB200/AT2221 in Adult Subjects With Late-Onset Pompe Disease (LOPD)

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Treatment Continued Group n=81 Participants Participants who received ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in the feeder study who continued on that dose in this long-term extension	Treatment Switched Group n=37 Participants Participants who received alglucosidase alfa/placebo in the feeder study who were switched to ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in this long-term extension	Total n=118 Participants Total of all reporting groups
Age, Categorical <=18 years	0 Participants n=41 Participants	0 Participants n=35 Participants	0 Participants n=76 Participants
Age, Categorical Between 18 and 65 years	69 Participants n=41 Participants	34 Participants n=35 Participants	103 Participants n=76 Participants
Age, Categorical >=65 years	12 Participants n=41 Participants	3 Participants n=35 Participants	15 Participants n=76 Participants
Age, Continuous	48.9 years STANDARD_DEVIATION 13.53 • n=41 Participants	46.0 years STANDARD_DEVIATION 13.47 • n=35 Participants	48.0 years STANDARD_DEVIATION 13.52 • n=76 Participants
Sex: Female, Male Female	48 Participants n=41 Participants	18 Participants n=35 Participants	66 Participants n=76 Participants
Sex: Female, Male Male	33 Participants n=41 Participants	19 Participants n=35 Participants	52 Participants n=76 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=41 Participants	0 Participants n=35 Participants	0 Participants n=76 Participants
Race (NIH/OMB) Asian	5 Participants n=41 Participants	5 Participants n=35 Participants	10 Participants n=76 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=41 Participants	0 Participants n=35 Participants	0 Participants n=76 Participants
Race (NIH/OMB) Black or African American	0 Participants n=41 Participants	1 Participants n=35 Participants	1 Participants n=76 Participants
Race (NIH/OMB) White	71 Participants n=41 Participants	30 Participants n=35 Participants	101 Participants n=76 Participants
Race (NIH/OMB) More than one race	5 Participants n=41 Participants	1 Participants n=35 Participants	6 Participants n=76 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants n=41 Participants	0 Participants n=35 Participants	0 Participants n=76 Participants
Enzyme Replacement Therapy (ERT)-experienced	61 Participants n=41 Participants	29 Participants n=35 Participants	90 Participants n=76 Participants
ERT-naive	20 Participants n=41 Participants	8 Participants n=35 Participants	28 Participants n=76 Participants
Age at diagnosis	40.3 years STANDARD_DEVIATION 13.82 • n=41 Participants	37.2 years STANDARD_DEVIATION 15.40 • n=35 Participants	39.3 years STANDARD_DEVIATION 14.35 • n=76 Participants

PRIMARY outcome

Timeframe: Entire extension study (mean = 40.5 months on treatment)

Population: Open-label extension (OLE) Safety Population defined as all subjects who took at least one dose of ATB200/AT2221 combination treatment in Study ATB200-07

Number of subjects with TEAE, TESAE, and TEAE leading to discontinuation during this long-term extension study

Outcome measures

Outcome measures
Measure	Treatment Continued Group n=81 Participants Participants who received ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in the feeder study who continued on that dose in this long-term extension	Treatment Switched Group n=37 Participants Participants who received alglucosidase alfa/placebo in the feeder study who were switched to ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in this long-term extension
Incidence of Treatment-emergent Adverse Events (TEAEs), Treatment-emergent Serious Adverse Events (TESAEs), and TEAEs Leading to Discontinuation of Study Drug Subjects with TEAEs leading to discontinuation	6 Participants	2 Participants
Incidence of Treatment-emergent Adverse Events (TEAEs), Treatment-emergent Serious Adverse Events (TESAEs), and TEAEs Leading to Discontinuation of Study Drug Subjects with TEAEs	80 Participants	37 Participants
Incidence of Treatment-emergent Adverse Events (TEAEs), Treatment-emergent Serious Adverse Events (TESAEs), and TEAEs Leading to Discontinuation of Study Drug Subjects with TESAEs	17 Participants	10 Participants
Incidence of Treatment-emergent Adverse Events (TEAEs), Treatment-emergent Serious Adverse Events (TESAEs), and TEAEs Leading to Discontinuation of Study Drug Subjects with TEAE leading to death	1 Participants	0 Participants

SECONDARY outcome

Timeframe: baseline, Week 208

Population: Motor function was evaluated using the Full Analysis Set (consisting of subjects in the study who had both a valid baseline and at least 1 post-baseline assessment for at least 1 of the main efficacy endpoints). Baseline and Month 208 assessment available for 39 subjects in the Treatment Continued Group and 18 subjects in the Treatment Switched Group.

Motor function was measured using the 6-minute walk distance (meters)

Outcome measures

Outcome measures
Measure	Treatment Continued Group n=39 Participants Participants who received ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in the feeder study who continued on that dose in this long-term extension	Treatment Switched Group n=18 Participants Participants who received alglucosidase alfa/placebo in the feeder study who were switched to ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in this long-term extension
Change From Baseline in 6-Minute Walk Distance (6MWD)	-33.3 meters Standard Deviation 37.60	-8.6 meters Standard Deviation 62.77

SECONDARY outcome

Timeframe: baseline, Week 208

Population: Pulmonary function was evaluated using the Full Analysis Set (consisting of subjects in the study who had both a valid baseline and at least 1 post-baseline assessment for at least 1 of the main efficacy endpoints). Baseline and Month 208 assessment available for 41 subjects in the Treatment Continued Group and 15 subjects in the Treatment Switched Group.

Pulmonary function was measured by sitting % predicted forced vital capacity (FVC)

Outcome measures

Outcome measures
Measure	Treatment Continued Group n=41 Participants Participants who received ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in the feeder study who continued on that dose in this long-term extension	Treatment Switched Group n=15 Participants Participants who received alglucosidase alfa/placebo in the feeder study who were switched to ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in this long-term extension
Change From Baseline in Sitting % Predicted Forced Vital Capacity (FVC)	-3.8 percent predicted FVC Standard Deviation 9.10	-0.5 percent predicted FVC Standard Deviation 8.54

SECONDARY outcome

Timeframe: baseline, Week 208

Population: Muscle strength was evaluated using the Full Analysis Set (consisting of subjects in the study who had both a valid baseline and at least 1 post-baseline assessment for at least 1 of the main efficacy endpoints). Baseline and Month 208 assessment available for 35 subjects in the Treatment Continued Group and 15 subjects in the Treatment Switched Group.

Strength was measured by manual muscle testing (MMT) using the Medical Research Council grading scale (0 to 5 points, with 5 indicating normal function). Change from baseline values \>0 represent improvement.

Outcome measures

Outcome measures
Measure	Treatment Continued Group n=35 Participants Participants who received ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in the feeder study who continued on that dose in this long-term extension	Treatment Switched Group n=15 Participants Participants who received alglucosidase alfa/placebo in the feeder study who were switched to ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in this long-term extension
Change From Baseline in Manual Muscle Testing (MMT) Lower Extremity Score	0.6 score on a scale Standard Deviation 4.38	0.4 score on a scale Standard Deviation 2.61

SECONDARY outcome

Timeframe: baseline, Week 208

Population: PROMIS-Physical Function was evaluated using the Full Analysis Set (consisting of subjects in the study who had both a valid baseline and at least 1 post-baseline assessment for at least 1 of the main efficacy endpoints). Baseline and Month 208 assessment available for 42 subjects in the Treatment Continued Group and 19 subjects in the Treatment Switched Group.

Physical Function Short Form 20a (v2.0) consisted of 20 questions. The first 14 questions were each scored on a scale from 1 to 5 as follows: 1 = unable to do; 2 = with much difficulty; 3 = with some difficulty; 4 = with a little difficulty; 5 = without any difficulty; the next 6 questions were each scored on a scale from 1 to 5 as follows: 1 = cannot do; 2 = quite a lot; 3 = somewhat; 4 = very little; 5 = not at all. The total score was calculated by summing up scores (1 to 5) across all items. Total scores range from 20 to 100. A higher score represented a better outcome.

Outcome measures

Outcome measures
Measure	Treatment Continued Group n=42 Participants Participants who received ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in the feeder study who continued on that dose in this long-term extension	Treatment Switched Group n=19 Participants Participants who received alglucosidase alfa/placebo in the feeder study who were switched to ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in this long-term extension
Change From Baseline in the Total Score for Patient-reported Outcomes Measurement Information System (PROMIS®) - Physical Function	-2.7 score on a scale Standard Deviation 8.38	-2.5 score on a scale Standard Deviation 6.14

SECONDARY outcome

Timeframe: baseline, Week 208

Population: PROMIS-Fatigue was evaluated using the Full Analysis Set (consisting of subjects in the study who had both a valid baseline and at least 1 post-baseline assessment for at least 1 of the main efficacy endpoints). Baseline and Month 208 assessment available for 42 subjects in the Treatment Continued Group and 19 subjects in the Treatment Switched Group.

Fatigue Short Form 8a consisted of 6 questions, each scored on a scale from 1 to 5 as follows: 1 = not at all; 2 = a little bit; 3 = somewhat; 4 = quite a bit; 5 = very much; and 2 questions, each scored on a scale from 1 to 5 as follows: 1 = never; 2 = rarely; 3 = sometimes; 4 = often; 5 = always. The total score was calculated by summing up scores (1 to 5) across all items resulting in a total score range from 6 (minimum) to 30 (maximum). A lower score represented lower fatigue symptoms.

Outcome measures

Outcome measures
Measure	Treatment Continued Group n=42 Participants Participants who received ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in the feeder study who continued on that dose in this long-term extension	Treatment Switched Group n=19 Participants Participants who received alglucosidase alfa/placebo in the feeder study who were switched to ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in this long-term extension
Change From Baseline in the Total Score for PROMIS® - Fatigue	1.5 score on a scale Standard Deviation 7.14	1.1 score on a scale Standard Deviation 3.72

SECONDARY outcome

Timeframe: baseline, Week 208

Population: GSGC was evaluated using the Full Analysis Set (consisting of subjects in the study who had both a valid baseline and at least 1 post-baseline assessment for at least 1 of the main efficacy endpoints). Baseline and Month 208 assessment available for 33 subjects in the Treatment Continued Group and 14 subjects in the Treatment Switched Group.

The GSGC consisted of a 10-meter walk for evaluation of gait, a 4-stair climb, Gowers' maneuver, and arising from a chair. Results of the GSGC included the time required to complete the individual tests, individual scores for each of the tests (1 to 7 points for each of gait, 4-stair climb, and Gowers' maneuver, and 1 to 6 points for arising from a chair), and a total score. GSGC total score was the sum of the component scores from the 4 functional tests. The total score ranged from a minimum of 4 points (normal performance) to a maximum of 27 points (worst performance).

Outcome measures

Outcome measures
Measure	Treatment Continued Group n=33 Participants Participants who received ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in the feeder study who continued on that dose in this long-term extension	Treatment Switched Group n=14 Participants Participants who received alglucosidase alfa/placebo in the feeder study who were switched to ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in this long-term extension
Change From Baseline in Gait, Stairs, Gower, Chair (GSGC) Test	0.5 score on a scale Standard Deviation 2.98	0.3 score on a scale Standard Deviation 1.59

SECONDARY outcome

Timeframe: baseline, Week 208

Population: EQ-5D-5L was evaluated using the Full Analysis Set (consisting of subjects in the study who had both a valid baseline and at least 1 post-baseline assessment for at least 1 of the main efficacy endpoints). Baseline and Month 208 assessment available for 42 subjects in the Treatment Continued Group and 19 subjects in the Treatment Switched Group.

The EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) questionnaire comprises 5 dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. Each dimension has 5 levels: Level 1=no problems, Level 2=slight problems, Level 3=moderate problems, Level 4=severe problems, and Level 5=extreme problems. In this categorical assessment, subjects were asked to indicate their health state by ticking the box next to the most appropriate statement in each of the 5 dimensions. Outcomes for change from baseline at Week 208 include 'no change', 'worsening' relative to baseline category, or 'improvement' relative to baseline category. Changes (worsening or improvement) are shown by magnitude of change (how many Levels) in each categorical assessment.

Outcome measures

Outcome measures
Measure	Treatment Continued Group n=42 Participants Participants who received ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in the feeder study who continued on that dose in this long-term extension	Treatment Switched Group n=19 Participants Participants who received alglucosidase alfa/placebo in the feeder study who were switched to ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in this long-term extension
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Mobility · No change from baseline	27 Participants	12 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Mobility · Worsening (1 level)	4 Participants	1 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Self-care · No change from baseline	25 Participants	12 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Self-care · Worsening (2 levels)	0 Participants	0 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Self-care · Worsening (3 or 4 levels)	0 Participants	0 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Self-care · Improvement (3 or 4 levels)	0 Participants	0 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Usual Activities · No change from baseline	23 Participants	6 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Usual Activities · Worsening (1 level)	5 Participants	6 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Usual Activities · Worsening (2 levels)	1 Participants	0 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Usual Activities · Worsening (3 or 4 levels)	0 Participants	0 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Usual Activities · Improvement (1 level)	11 Participants	6 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Pain/discomfort · Worsening (1 level)	8 Participants	1 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Pain/discomfort · Worsening (2 levels)	0 Participants	2 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Anxiety/depression · No change from baseline	29 Participants	13 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Anxiety/depression · Worsening (3 or 4 levels)	0 Participants	0 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Anxiety/depression · Improvement (1 level)	7 Participants	5 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Anxiety/depression · Improvement (2 levels)	1 Participants	0 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Mobility · Worsening (2 levels)	0 Participants	0 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Mobility · Worsening (3 or 4 levels)	0 Participants	0 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Mobility · Improvement (1 level)	9 Participants	4 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Mobility · Improvement (2 levels)	2 Participants	2 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Mobility · Improvement (3 or 4 levels)	0 Participants	0 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Self-care · Worsening (1 level)	5 Participants	4 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Self-care · Improvement (1 level)	9 Participants	2 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Self-care · Improvement (2 levels)	3 Participants	1 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Usual Activities · Improvement (2 levels)	2 Participants	1 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Usual Activities · Improvement (3 or 4 levels)	0 Participants	0 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Pain/discomfort · No change from baseline	22 Participants	14 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Pain/discomfort · Worsening (3 or 4 levels)	0 Participants	0 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Pain/discomfort · Improvement (1 level)	10 Participants	2 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Pain/discomfort · Improvement (2 levels)	2 Participants	0 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Pain/discomfort · Improvement (3 or 4 levels)	0 Participants	0 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Anxiety/depression · Worsening (1 level)	4 Participants	1 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Anxiety/depression · Worsening (2 levels)	1 Participants	0 Participants
Change From Baseline in EuroQol 5 Dimensions 5 Levels (EQ-5D-5L) Responses Anxiety/depression · Improvement (3 or 4 levels)	0 Participants	0 Participants

SECONDARY outcome

Timeframe: baseline, Week 208

Population: The SGIC was evaluated using the Full Analysis Set (consisting of subjects in the study who had both a valid baseline and at least 1 post-baseline assessment for at least 1 of the main efficacy endpoints). Baseline and Month 208 assessment available for 42 subjects in the Treatment Continued Group and 19 subjects in the Treatment Switched Group.

The Subject's Global Impression of Change overall physical well-being (question 1) is scored on a 7-point rating scale ranging from "very much worse" to "very much improved."

Outcome measures

Outcome measures
Measure	Treatment Continued Group n=42 Participants Participants who received ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in the feeder study who continued on that dose in this long-term extension	Treatment Switched Group n=19 Participants Participants who received alglucosidase alfa/placebo in the feeder study who were switched to ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in this long-term extension
Change From Baseline in Overall Physical Well-being (Subject's Global Impression of Change [SGIC], Question 1) Much worse	0 Participants	1 Participants
Change From Baseline in Overall Physical Well-being (Subject's Global Impression of Change [SGIC], Question 1) Somewhat worse	12 Participants	2 Participants
Change From Baseline in Overall Physical Well-being (Subject's Global Impression of Change [SGIC], Question 1) Somewhat improved	9 Participants	3 Participants
Change From Baseline in Overall Physical Well-being (Subject's Global Impression of Change [SGIC], Question 1) Much improved	4 Participants	3 Participants
Change From Baseline in Overall Physical Well-being (Subject's Global Impression of Change [SGIC], Question 1) Very much worse	0 Participants	0 Participants
Change From Baseline in Overall Physical Well-being (Subject's Global Impression of Change [SGIC], Question 1) No change	15 Participants	9 Participants
Change From Baseline in Overall Physical Well-being (Subject's Global Impression of Change [SGIC], Question 1) Very much improved	2 Participants	1 Participants

SECONDARY outcome

Timeframe: baseline, Week 208

Population: The PGIC was evaluated using the Full Analysis Set (consisting of subjects in the study who had both a valid baseline and at least 1 post-baseline assessment for at least 1 of the main efficacy endpoints). Baseline and Month 208 assessment available for 40 subjects in the Treatment Continued Group and 19 subjects in the Treatment Switched Group.

The Physician's Global Impression of Change (PGIC) is designed to record the physician's assessment of the subject's status, taking into account the subject's signs and symptoms and other neuromuscular symptoms, and signs relative to their status at the Baseline Visit. The PGIC is based on a single item that is scored on a 7-point rating scale ranging from 1 "very much worse" to 7 "very much improved."

Outcome measures

Outcome measures
Measure	Treatment Continued Group n=40 Participants Participants who received ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in the feeder study who continued on that dose in this long-term extension	Treatment Switched Group n=19 Participants Participants who received alglucosidase alfa/placebo in the feeder study who were switched to ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in this long-term extension
Change From Baseline in Physician's Global Impression of Change (PGIC) Overall Status Very much worse	0 Participants	0 Participants
Change From Baseline in Physician's Global Impression of Change (PGIC) Overall Status Much worse	0 Participants	1 Participants
Change From Baseline in Physician's Global Impression of Change (PGIC) Overall Status Somewhat improved	6 Participants	5 Participants
Change From Baseline in Physician's Global Impression of Change (PGIC) Overall Status Much improved	3 Participants	1 Participants
Change From Baseline in Physician's Global Impression of Change (PGIC) Overall Status Somewhat worse	9 Participants	3 Participants
Change From Baseline in Physician's Global Impression of Change (PGIC) Overall Status No change	21 Participants	8 Participants
Change From Baseline in Physician's Global Impression of Change (PGIC) Overall Status Very much improved	1 Participants	1 Participants

SECONDARY outcome

Timeframe: baseline, Week 208

Population: The Full Analysis Set was used in analyses of biomarkers. A total of 40 subjects in the Treatment Continued Group and 18 subjects in the Treatment Switched Group had CK values at Week 208.

Percent change from baseline to Week 208 in the levels of biomarker creatine kinase (CK)

Outcome measures

Outcome measures
Measure	Treatment Continued Group n=40 Participants Participants who received ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in the feeder study who continued on that dose in this long-term extension	Treatment Switched Group n=18 Participants Participants who received alglucosidase alfa/placebo in the feeder study who were switched to ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in this long-term extension
Percent Change From Baseline in Creatine Kinase (U/L)	-17.8 percent change from baseline Standard Deviation 27.93	-29.0 percent change from baseline Standard Deviation 37.11

SECONDARY outcome

Timeframe: baseline, Week 208

Population: The Full Analysis Set was used in analyses of biomarkers. A total of 39 subjects in the Treatment Continued Group and 17 subjects in the Treatment Switched Group had urine hex4 values at Week 208.

Percent change from baseline to Week 208 in the levels of biomarker urine Hex4.

Outcome measures

Outcome measures
Measure	Treatment Continued Group n=39 Participants Participants who received ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in the feeder study who continued on that dose in this long-term extension	Treatment Switched Group n=17 Participants Participants who received alglucosidase alfa/placebo in the feeder study who were switched to ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in this long-term extension
Percent Change From Baseline in Urine Hex4 (mmol/Mol Creatinine)	-16.7 percent change from baseline Standard Deviation 43.70	-62.4 percent change from baseline Standard Deviation 17.80

SECONDARY outcome

Timeframe: baseline, Week 208

Population: In the Treatment Continued group, 76 subjects had immunogenicity data at baseline, and 41 subjects had data at Week 208. In the Treatment Switched group, 36 subjects had immunogenicity data at baseline and 20 subjects had data at Week 208.

Immunogenicity was assessed by the number (%) of subjects with positive specific anti-cipaglucosidase antibodies at baseline and at Week 208

Outcome measures

Outcome measures
Measure	Treatment Continued Group n=76 Participants Participants who received ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in the feeder study who continued on that dose in this long-term extension	Treatment Switched Group n=36 Participants Participants who received alglucosidase alfa/placebo in the feeder study who were switched to ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in this long-term extension
Proportion of Subjects With Positive Anti-drug Antibodies at Baseline and Week 208 Week 208	34 Participants	17 Participants
Proportion of Subjects With Positive Anti-drug Antibodies at Baseline and Week 208 Baseline	63 Participants	30 Participants

Adverse Events

Treatment Continued Group

Serious events: 17 serious events

Other events: 80 other events

Deaths: 1 deaths

Treatment Switched Group

Serious events: 10 serious events

Other events: 37 other events

Deaths: 0 deaths

Serious adverse events

Other adverse events

Additional Information

MedInfo

Amicus Therapeutics, Inc.

Phone: 001 609-662-2000

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place

Measure	Treatment Continued Group n=81 participants at risk Participants who received ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in the feeder study who continued on that dose in this long-term extension	Treatment Switched Group n=37 participants at risk Participants who received alglucosidase alfa/placebo in the feeder study who were switched to ATB200 (20 mg/kg) co-administered with AT2221 (260 mg) in this long-term extension
Blood and lymphatic system disorders Anemia	1.2% 1/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	0.00% 0/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Cardiac disorders Acute myocardial infarction	1.2% 1/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	0.00% 0/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Cardiac disorders Conduction disorder	1.2% 1/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	0.00% 0/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Cardiac disorders Arrhythmia	0.00% 0/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	2.7% 1/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Eye disorders Conjunctival hemorrhage	1.2% 1/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	0.00% 0/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Gastrointestinal disorders Intestinal perforation	0.00% 0/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	2.7% 1/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Gastrointestinal disorders Pancreatitis	0.00% 0/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	2.7% 1/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
General disorders Chills	1.2% 1/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	0.00% 0/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
General disorders Chest pain	0.00% 0/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	2.7% 1/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Hepatobiliary disorders Bile duct stone	0.00% 0/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	2.7% 1/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Hepatobiliary disorders Cholecystitis acute	0.00% 0/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	2.7% 1/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Immune system disorders Hypersensitivity	1.2% 1/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	0.00% 0/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Immune system disorders Anaphylactic reaction	0.00% 0/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	2.7% 1/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Infections and infestations COVID-19	1.2% 1/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	0.00% 0/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Infections and infestations COVID-19 pneumonia	1.2% 1/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	2.7% 1/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Infections and infestations Pneumonia	1.2% 1/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	2.7% 1/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Infections and infestations Urinary tract infection	1.2% 1/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	0.00% 0/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Injury, poisoning and procedural complications Tibia fracture	2.5% 2/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	0.00% 0/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Injury, poisoning and procedural complications Ankle fracture	1.2% 1/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	0.00% 0/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Injury, poisoning and procedural complications Femur fracture	1.2% 1/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	0.00% 0/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Injury, poisoning and procedural complications Fibula fracture	1.2% 1/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	0.00% 0/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Injury, poisoning and procedural complications Fractured sacrum	1.2% 1/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	0.00% 0/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Injury, poisoning and procedural complications Hip fracture	1.2% 1/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	0.00% 0/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Injury, poisoning and procedural complications Limb injury	1.2% 1/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	0.00% 0/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Injury, poisoning and procedural complications Traumatic fracture	1.2% 1/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	0.00% 0/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Injury, poisoning and procedural complications Pulmonary contusion	0.00% 0/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	2.7% 1/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Injury, poisoning and procedural complications Road traffic accident	0.00% 0/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	2.7% 1/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Musculoskeletal and connective tissue disorders Intervertebral disc protrusion	1.2% 1/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	0.00% 0/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Musculoskeletal and connective tissue disorders Back pain	0.00% 0/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	2.7% 1/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Neoplasms benign, malignant and unspecified (incl cysts and polyps) B-cell small lymphocytic lymphoma	1.2% 1/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	0.00% 0/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Nervous system disorders Dementia with Lewy bodies	1.2% 1/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	0.00% 0/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Nervous system disorders Hypoesthesia	1.2% 1/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	0.00% 0/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Nervous system disorders Lumbosacral radiculopathy	1.2% 1/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	0.00% 0/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Nervous system disorders Transient ischemic attack	1.2% 1/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	0.00% 0/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Psychiatric disorders Delirium	0.00% 0/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	2.7% 1/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Respiratory, thoracic and mediastinal disorders Hypoxia	1.2% 1/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	0.00% 0/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Respiratory, thoracic and mediastinal disorders Pulmonary embolism	1.2% 1/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	0.00% 0/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Respiratory, thoracic and mediastinal disorders Pneumothorax	0.00% 0/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	2.7% 1/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Skin and subcutaneous tissue disorders Urticaria	0.00% 0/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	2.7% 1/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).
Vascular disorders Hypotension	0.00% 0/81 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).	2.7% 1/37 • Adverse event data collected over duration of the study. Duration of participation varied by patient (range: 1 to 58 months).