Participants enrolled in the AVRO-RD-01-201 study will be offered participation in the AVRO-RD-01-LTF01 study. The Baseline visit for the AVRO-RD-01-LTF01 study will coincide with the participant's last visit in the AVRO-RD-01-201 study. Participants confirmed eligible for the AVRO-RD-01-LTF01 study will be asked to return for study visits at approximately 6-month intervals for the first 4 years and annually thereafter for 10 years (for a total of 15 years from AVR-RD-01 infusion) during which time continued safety, engraftment, and efficacy of treatment will be assessed.
This is a multinational, long-term follow-up study to assess the long-term safety and durability of AVR-RD-01 treatment in participants who received a single dose administration of lentiviral gene therapy in Study AVRO-RD-01-201 (treatment study). No investigational product will be administered in this study. Participants will continue periodic safety and efficacy assessments in this long-term follow-up study up to 15 years from AVR-RD-01 gene therapy infusion.