Fenfluramine hydrochloride is in clinical development as a treatment for paediatric and adult patients with Lennox-Gastaut syndrome. Lennox-Gastaut syndrome is a rare and severe form
of epilepsy that is most commonly found in children. It is characterised by slow mental development and various types of seizures that are difficult to treat. As patients enter into
adulthood, the emergent comorbidities associated with the syndrome (such as impaired mobility, learning and behaviour) become more apparent and add further burden to the
patient and their careers, alongside management of their seizures. Lennox-Gastaut syndrome can be difficult to diagnose when children are young due to the evolving nature of
the seizures experienced. Lennox-Gastaut syndrome is highly resistant to antiepileptic drugs.
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.
Tofersen (BIIB067) is in clinical development for the treatment of amyotrophic lateral sclerosis (ALS – also known as motor neurone disease) caused by mutations in the SOD1 gene (SOD1-ALS). ALS is a progressive disease of the nervous system, where nerve cells in the brain and spinal cord that control voluntary movement gradually deteriorate, causing loss of muscle function and paralysis. ALS is a debilitating and life-threatening disease. The gradual loss of neurons leads to a paralysing effect on muscles used for breathing, which usually leads to death from respiratory failure.