Cree Leukoencephalopathy (CLE) is a rare and fatal neurodegenerative disorder predominantly affecting the Cree population in Northern Quebec. Characterized by progressive white matter degeneration, this condition leads to severe neurological impairment and decline, leading to premature death. Despite its significant impact on the affected population, there are currently no effective treatments for CLE. CLE is caused by a single founder pathogenic variant in the EIF2B5 gene and is therefore allelic to VWM.

Fosigotifator (FGT, ABBV-CLS-7262) has been developed and its safety and efficacy are currently being studied in a multi-center Phase 1b/2 clinical trial for Vanishing White Matter (VWM) by Calico in collaboration with AbbVie.

This study aims to provide under compassionate use program access to an investigational drug (FGT) for a patient diagnosed with CLE/VWM disease which has no treatment options currently available. The study will also evaluate the risk/benefit of FGT in slowing or halting the progression of white matter degeneration in a patient with CLE. By targeting the underlying pathophysiological mechanisms of white matter damage, FGT is expected to alleviate neurological symptoms and improve the quality of life for the patient. The outcomes of this study could provide critical insights into the disease's management and pave the way for the development of targeted therapies, ultimately offering hope to a population with limited treatment options.

Inclusion Criteria:

The patient meets the following criteria:

• Molecularly confirmed diagnosis of CLE
• Pre-symptomatic or early symptomatic patient
• Signed informed consent from the Legal Guardians/caregivers (parents)

Exclusion Criteria:

N/A