The study will be a randomized, double blind, placebo-controlled study of the safety and efficacy of PRX-102 in ERT naïve male patients randomized 1:1. Patient age will be 14 to 45 years. Patients must have diarrhea defined as ≥ 3 stools a day with an average consistency of ≥ 5.5 on the Bristol Stool Form Scale (BSFS) by patient electronic diary and moderate to severe gastrointestinal symptoms as defined by the Irritable Bowel Symptom Severity Score (IBSSS) Part 1 average > 175 derived from at least two IBSSS assessments during screening period. Patients will receive intravenous infusions of PRX-102 1 mg/kg or placebo every two weeks for 6 months.