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New Phase 2 Study of Repurposed Drug for SMA

06 December 2017

Catalyst Pharmaceuticals have announced that they are to investigate the potential of a drug called Firdapse as a treatment for people with SMA Type 3.

The safety, tolerability, and efficacy of Firdapse will be assessed in a small-scale, proof-of-concept phase 2 clinical trial that will include approximately 12 ambulatory SMA patients.

Firdapse is a drug capable of modifying the electrical activity of nerve cells, and it has been approved in Europe for the treatment of a neuromuscular disease called Lambert Eaton Myasthenic Syndrome, or LEMS.

The neuromuscular junction (NMJ), which is the specialised connection between lower motor neurons and their target muscles, deteriorates in LEMS patients. This impairs the transmission of electrical signals from the nerves to muscles, resulting in muscle weakness.

Firdapse, which is also called amifampridine and 3,4-diaminopyridine, is able to increase the time that nerves are able to conduct signals to the muscle. This can cause increased muscle activity in LEMS patients.

Given that neurotransmission and the NMJ are also affected in SMA models and patients, Catalyst Pharmaceuticals have decided to assess the effects of Firdapse in SMA Type 3. In this respect, Firdapse is being repurposed for the potential treatment of SMA. This has previously been done with a similar drug called 4-aminopyridine, which also enhances nerve to muscle electrical signalling (for further information click here).

Firdapse will not cure SMA as it is not targeting the genetic cause of the disease, i.e. the low levels of survival motor neuron (SMN) protein that lead to lower motor neuron degeneration. However, it may improve the function of the remaining lower motor neurons in patients with less severe forms of the disease, and therefore provide useful improvements in muscle force.

Results are expected from this phase 2 study of Firdapse in early 2019.

Further Information

Catalyst Pharmaceuticals press release