Risdiplam is in clinical development for the treatment of spinal muscular atrophy (SMA). SMA is a severe, inherited, neuromuscular lethal disease that gets worse over time. Patients with the disease lack a survival motor neuron (SMN) 1 gene and fewer copies of SMN2. This gene produces a protein called SMN protein, which is essential for the normal functioning and survival of motor neurons (nerves from the brain and spinal cord that control muscle movements). SMA is usually diagnosed within the first few months of life for the most severe subtype (type I). Depending on the type of SMA, an individual’s physical strength and their ability to walk, eat or breathe can be significantly diminished or lost. SMA causes the muscles to fall into disuse, leading to muscle wasting (atrophy) and weakness, and in its most common form (type I), loss of swallowing function, breathing failure and death within the first few years of life. There is currently no cure for SMA but there are treatments to help manage the symptoms.
Risdiplam is an investigational, oral medicine that is designed to increase SMN protein levels in the central nervous system and throughout the body and thereby reducing the symptoms of the disease. If licensed risdiplam will offer a treatment option for paediatric and adult patients with SMA.
Fenfluramine belongs to a class of drugs called the selective serotonin releasing agonists which stimulates multiple 5-HT receptor sub-types through the release of serotonin. Fenfluramine may also act on other receptors and these actions may help to reduce the frequency of seizures. When added to other standard anti-epileptic treatments, fenfluramine hydrochloride has shown preliminary evidence of reducing seizure frequency. If licensed, fenfluramine hydrochloride may offer an additional treatment option for patients with Lennox-Gastaut syndrome.