OTL-200 is in development for the treatment of metachromatic leukodystrophy (MLD). MLD is a rare hereditary disease caused by changes (mutations) in the arylsulfatase A (ARSA) gene. The disease is characterized by accumulation of fats that causes the destruction of the protective fatty layer surrounding the nerves in the brain and spinal cord. MLD is a progressive disease that is heterogeneous regarding the age of onset, disease progression and symptoms severity. Symptoms vary by subtype but can include difficulty talking, seizures, difficulty walking, personality changes, and behaviour and personality changes. There are currently no effective treatments for MLD. Drugs can be given to treat the symptoms as they occur, such as muscle spasms, infections, pain and seizures.
OTL-200 is a gene therapy that involves extraction of certain stem cells from a patient’s bone marrow or blood. These stem cells are genetically modified and then returned to the patient by intravenous infusion to deliver the corrected version of the gene to the cells in charge of creating key proteins. The corrected cells then produce the protein that was missing or defective prior to treatment, aiming to halt disease progression or modify its natural course. If licensed, OTL-200 will offer a potentially curative treatment option for patients with MLD, who currently have no effective therapies available.
Etrolizumab is a new monoclonal antibody (an immune protein) delivered by subcutaneous injection. The treatment works by targeting molecules called integrins to control the immune response and prevent the accumulation of immune molecules, which cause inflammation in individuals with a form of ulcerative colitis where inflammation is not mediated by a signalling protein called tumour necrosis factors (TNF) alpha (‘non-TNF-α’) and who are therefore intolerant to TNF blockers. This represents a new target group as current therapies focus mainly on anti-TNF inflammation. In one study, etrolizumab showed a greater reduction of intestinal lymphocyte infiltration in comparison to standard treatment.