A Phase 1b, Open-label, Multicenter Dose-escalation Study to Evaluate the Safety, Tolerability, and Preliminary Efficacy of a Single Subretinal Dose of ASP2020 in Participants With Macular Dystrophies With a Stargardt-type Clinical Presentation

Summary

Macular dystrophies are a group of inherited eye conditions that affect the macula. The macula is in the center of the retina, the light sensitive part at the back of the eye. In people with macular dystrophies, some of the cells in the macula gradually stop working and may die over time. This leads to loss of central vision, which can make it harder to read, recognize faces or see fine details. What's seen out of the corner of the eye (peripheral vision) is mostly unaffected. Stargardt disease (STGD) is a type of macular dystrophy which is caused by 1 faulty gene (ABCA4). Vision loss most typically begins in childhood or teenage years but may also develop in adulthood. As well as STGD, there are other macular dystrophies that look very similar to STGD and are called STGD-like macular dystrophies. These are caused by many other different genes. Together, STGD and STGD-like conditions can be called STGD-type macular dystrophies. This is an early development study of ASP2020 in adults, teenagers, and children with STGD-type macular dystrophies. ASP2020 are human stem cells which have been changed into cells found in the macula. In this study ASP2020 will be given to people for the first time. The main aim of the study is to check the safety of ASP2020 and how well people tolerate it. Other aims are to learn if people have an immune reaction to ASP2020, and if there are signs that the stem cells replace damaged cells in the retina, and vision improves for people with STGD-type macular dystrophies. ASP2020 will be given as a single injection into the eye, under the retina. This requires a surgical procedure where the person is put to sleep by a general anesthetic. At the end of surgery, a steroid will be injected into the eye to reduce any swelling. The study has 2 parts. In Part 1, different small groups will receive a lower to higher dose of ASP2020. This is done to find a suitable dose to use in Part 2. The adults will receive the lower dose and higher dose before the teenagers. There will be a 6-month gap between the last adult receiving the lower dose of ASP2020 and the first teenager receiving the same lower dose. This will also happen for the last adult receiving the higher dose of ASP2020 and the first teenager receiving the higher dose of ASP2020. Any medical problems will be recorded for each dose in each group. Children will not receive ASP2020 in Part 1. In Part 2, different groups of adults, teenagers and children will receive the most suitable dose of ASP2020 worked out from Part 1. People will be in the study for about 1 year and they will visit the clinic several times. In both parts of the study, safety checks will be done at each visit, and the study doctors will continue to check for any medical problems throughout the study. Various eye tests and eye imaging will be done throughout the study. Blood tests will also be done at some of the visits during the study.