Core (Part 1)~Once a participant consents, he/she will complete the screening period within 30 days.~Eligible participants will have baseline assessments completed 30 days later and then will be randomized into one of two treatment arms: AVR-RD-02 arm or ERT control arm.~If randomized to the AVR-RD-02 arm, the participant will enter the pre-gene therapy infusion period (approximately 15 weeks), which consists of mobilization, apheresis, AVR-RD-02 preparation and testing for release, discontinuation of ERT, and conditioning. The participant will then receive the AVR-RD-02 gene therapy (1 day) followed by a 52-week follow-up period in which periodic safety and efficacy assessments will be performed. Participants will not receive ERT after gene therapy infusion unless indicated by pre-specified laboratory and clinical criteria.~If randomized to the ERT Control arm, the participant will remain on their prescribed ERT regimen for 52-week observation period with approximately 4 study visits during this time.~ERT-crossover (Part 2)~After 52 weeks of observation in Part 1, participants in the ERT Control Arm will have the opportunity to enter Part 2 and receive AVR-RD-02. They will start with baseline assessments and follow a similar schedule to the schedule followed by participants assigned to AVR-RD-02 in the Core Study (Part 1).
The purpose of this study is to evaluate the efficacy and safety of autologous hemotopoietic stem cell (HSC) gene therapy, AVR-RD-02, compared to enzyme replacement therapy, for the treatment of Gaucher disease Type 3 in male and female participants aged 2 to 25 years.~The study will consist of 2 parts - Core (Part 1) followed by the ERT-crossover (Part 2)