AT-1501 (anti-CD40L) is an investigational drug being developed by Anelixis Therapeutics, a subsidiary of the ALS Therapy Development Institute (ALS TDI), to treat amyotrophic lateral sclerosis (ALS).

How AT-1501 works

ALS is a progressive neurodegenerative disease for which there is currently no cure. The symptoms are caused by damage to and death of motor neurons (nerve cells that control the movement of muscles), and while the exact cause of the disease is unknown, researchers know that the immune system contributes to its progression by causing inflammation in the nervous system, leading to damage in motor neurons.

AT-1501 is an antibody against a protein called CD40 ligand (CD40L). Antibodies are proteins designed to bind to and block a particular target. CD40L is found on the outside of some immune cells; it’s a protein that’s involved in regulating the immune response and that can trigger inflammation in the spinal cord. The CD40L pathway has been shown to be overactive in ALS patients.

The exact mechanism of AT-1501 in ALS is unknown, but it is thought that by inhibiting CD40L, the potential therapy could block or delay the activation of the damaging inflammatory immune response. This could slow the progression of ALS symptoms and increase survival. It may also delay the start of symptoms in patients at risk of developing ALS.

AT-1501 in preclinical studies

AT-1501 has not yet been investigated in humans. However, it has been through extensive preclinical studies with positive results.

For example, a preclinical study using a mouse model of ALS has shown that when AT-1501 significantly increased the time until disease onset in the animals, increased their survival, and improved their body weight, compared to mice that were given a placebo. The results of this study have been published in the prestigious scientific journal Nature Genetics.

In the wake of these results, studies testing the safety of AT-1501 in non-human primates were initiated in 2017. These studies are scheduled to be completed in late 2017 and are likely to predict whether the treatment will be safe to test in humans.

The ALS TDI is currently raising money to advance AT-1501 to clinical trials in humans. They estimate it will take $30 million to progress to Phase 2 clinical trials to assess whether the therapy is safe and effective. Their goal is to begin Phase 1 clinical trials in humans in 2018.


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