The MPS Society is aware of an announcement from REGENXBIO regarding its investigational gene therapy programs RGX-111 for MPS I (Hurler syndrome) and RGX-121 for MPS II (Hunter syndrome).
The U.S. Food and Drug Administration (FDA) has placed both programs on clinical hold following the identification of a potential safety event in the Phase I/II study of RGX-111 (Hurler Syndrome).
The event involved a child who had previously received RGX-111 and was later found to have a brain tumour during routine MRI monitoring. The child had no symptoms at the time of discovery, the tumour was surgically removed and the child is reported to be doing well.
At this time, no direct cause has been identified. Investigations are ongoing to determine whether there is any connection between this event and the investigational treatment.
No similar safety events have been reported in patients treated with RGX-121. However, the FDA cited similarities between the two programs in its decision to place both trials on hold.
A clinical hold means that no new patients can be enrolled and certain trial activities are paused while the FDA reviews available safety information. It does not mean that the trials have been permanently stopped.
REGENXBIO has stated that it intends to continue discussions with the FDA to determine appropriate next steps and what information may be required to lift the hold.
Senior members of the MPS Society UK will be meeting directly with REGENXBIO in the coming week. We will share updates with the MPS community as soon as further information becomes available.
We recognise that this news may be worrying for families affected by MPS I and MPS II, particularly those awaiting new treatment options. The MPS Society Support Team remains committed to providing accurate, timely information and ongoing support to the MPS community.
MPS Society Patient Services Team
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Families with questions or concerns are encouraged to speak with their clinical teams or to contact the MPS Society for support.
