Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that is also known as Lou Gehrig’s Disease. It results in deterioration of motor neurons in charge of sending signals to control voluntary movement. Early symptoms of ALS include muscle cramps, tight muscles, slurred speech, muscle weakness, and difficulty chewing/swallowing. Eventually, patient autonomy declines and affected individuals tend to suffer respiratory failure within 3-5 years of disease onset.
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SOD1-ALS is a specific type of ALS that makes up 3% of the ALS cases, which affects roughly 330 people in the United States. SOD1 is a gene, which in ALS causes patients bodies to produce a toxic form of SOD1 protein that causes motor neuron degeneration, ultimately resulting in weak muscles. It is an extremely painful process as well because people lose the ability to do basic tasks, such as speak, eat, and eventually breathe. This is a highly anticipated rare disease that requires attention for the patients that have it.
Tofersen is Biogen’s solution; it is an antisense oligonucleotide (ASO), and it binds to SOD1 mRNA which results in reduction of SOD1 protein production. This is an ongoing study called ATLAS, which is actually still recruiting. ATLAS has shown promising results in the treatment of tofersen for SOD1-ALS, and many ALS associations are showing their support for the government to give accelerated approval so SOD1-ALS can reach patients as soon as possible. Tofersen has had side effects of neurofilament reductions, which can be a marker for disease progression since it measures axonal injury and neurodegeneration. The FDA voted and concluded this reduction of neurofilament likely shows clinical benefit of tofersen, since it does slow down neurodegeneration. This is a huge step forward, as this opens the door to a probable approval for tofersen to treat SOD1-ALS and provide much needed attention to a rare disease.