Methodology: This is a phase II, single center, randomized, double-blind, placebo-controlled, study in patients with a diagnosis of anti-AchR antibody positive myasthenia gravis.~Study Design: The clinical trial will be conducted over a 6-week treatment period.~Group A: Patients currently taking pyridostigmine and experiencing pyridostigmine-related gastrointestinal (GI) adverse events (AEs) within the past 7 days~Group B: Patients not currently taking pyridostigmine due to GI AEs or that had their dose reduced due to pyridostigmine related GI AEs Group A will be enrolled in the study and randomized to either the control (pyridostigmine+ placebo) or the test group (pyridostigmine + ondansetron) and treated for 6 weeks. Following enrolment, patients may (if needed) titrate up their pyridostigmine dose at the investigator's discretion each week to the highest dose deemed appropriate, tolerable and safe by the Investigator.~Group B patients not currently taking pyridostigmine due to GI AEs will initiate pyridostigmine at a dose determined by the investigator based on the patient's history and may titrate as deemed tolerable and safe by Investigator during screening; patients on a reduced dose due to pyridostigmine related GI AEs may titrate pyridostigmine as deemed tolerable and safe by the investigator during screening. If patients in Group B experience GI AEs that fulfil enrolment criteria, along with all other inclusion/exclusion criteria, they will be enrolled into the study at that dose and randomized to either the control (pyridostigmine+ placebo) or the test group (pyridostigmine + ondansetron) and treated for 6 weeks. Following enrolment, patients may (if needed) titrate up their pyridostigmine dose at the investigator's discretion each week to the highest dose deemed appropriate, tolerable and safe by the Investigator.
This is a phase II, single center, randomized, double-blind, placebo-controlled, study in patients with a diagnosis of anti-AchR antibody positive myasthenia gravis.