An Extension Study Assessing the Safety and Efficacy of AVTX-803 in Subjects With Leukocyte Adhesion Deficiency Type II

Study Overview
=================
Brief Summary
-----------------
The primary objective of this extension study is to assess the long-term safety and efficacy of AVTX-803 in subjects with LAD II (SLC35C1-CDG).

Official Title
-----------------
A Phase 3, Open-Label, Extension Study to Assess the Long-term Safety and Efficacy of AVTX-803 in Subjects With Leukocyte Adhesion Deficiency Type II (LAD II)

Conditions
-----------------
Leukocyte Adhesion Deficiency

Intervention / Treatment
-----------------
* Drug: AVTX-803


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Subject must have completed protocol AVTX-803-LAD-301 Subject has biochemically and genetically proven LAD II (SLC35C1-CDG) Exclusion Criteria: Subject has severe anemia defined as hemoglobin <8.0 g/dL (<4.9 mmol/L) Subject has impaired renal function as defined by an eGFR <90 mL/min Subject has known or suspected intolerance or hypersensitivity to fucose or any ingredients of the investigational product In the investigator's opinion, subject has a history of failure to respond to fucose at adequate dosing

Ages Eligible for Study
-----------------
Minimum Age: 6 Months
Maximum Age: 75 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: AVTX-803<br>AVTX-803 at a dose specified by the investigator up to 5 times a day not to exceed 1700 mg/kg/day | Drug: AVTX-803<br>* L-fucose crystalline powder<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of treatment emergent adverse events reported during the study attributable to AVTX-803. |  | Through study completion, an average of 1 year. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sialyl-Lewis X antigen expression on leukocytes |  | At 6 months | 
| Change from Baseline in the composite Nijmegen Pediatric Congenital Disorders of Glycosylation (CDG) Rating Scale (NPCRS) | The NPCRS comprises 3 sections, with each section containing specific items relevant to the assessment of subjects with CDG. Section I (Current Function); Section II (System Specific Involvement); and Section III (Current Clinical Assessment). The sum of the scores is used to scale patients into 3 domains: mild (0-14), moderate (15-25), and severe (>26) category. | Through study completion, an average of 1 year. | 
| Change from Baseline in the individual parameters of the Nijmegen Pediatric Congenital Disorders of Glycosylation (CDG) Rating Scale (NPCRS) | The NPCRS comprises 3 sections, with each section containing specific items relevant to the assessment of subjects with CDG. Section I (Current Function); Section II (System Specific Involvement); and Section III (Current Clinical Assessment). The sum of the scores is used to scale patients into 3 domains: mild (0-14), moderate (15-25), and severe (>26) category. | Through study completion, an average of 1 year. | 
| Goal Attainment Score (GAS) | The parent (or subject) formulates 3 individual goals for improving quality of life. Typically, these goals affect mobility, independence, and disease-related health aspects. These goals will be re-evaluated and scored by the parent or subject at each study visit within a scale of -2 to +2. | Through study completion, an average of 1 year. | 
| Clinician Global Impression of Severity (CGI-S) | The CGI-S scale is a 7-point scale that assesses the severity of the subject's severity of disease/illness. 1=Normal, not ill at all; 2=borderline ill; 3=mildly ill; 4=moderately ill; 5=markedly ill; 6= severely ill; 7=among the most extreme ill. | Through study completion, an average of 1 year. |