FDA names CB03, aiming to protect neurons, an orphan drug for ALS

Potential therapy, in Phase 1 trials, works to lower damaging hyperexcitability

Andrea Lobo, PhD avatar

by Andrea Lobo, PhD |

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The U.S. Food and Drug Administration (FDA) has given orphan drug designation to CB03, Zhimeng Biopharma’s small molecule treatment candidate for amyotrophic lateral sclerosis (ALS).

CB03 is designed to bolster nerve cell health by regulating potassium channels on these cells, reducing the hyperexcitability that is damaging to neurons.

Orphan drug status aims to encourage the development of treatments for rare diseases, those affecting fewer than 200,000 people in the U.S. It provides benefits such as exemption from FDA application fees, assistance in clinical trial design, and seven years of market exclusivity if the therapy is approved.

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CB03’s safety and tolerability in Phase 1 trials in US, Australia

Available ALS treatments aim to help with managing disease symptoms and in slowing progression.

CB03, a potential therapy for ALS and other conditions of the central nervous system (the brain and spinal cord), is being evaluated in Phase 1 clinical trials taking place in the U.S. (NCT05499260) and Australia (NCT05502549).

They are assessing the safety, tolerability, and pharmacological properties of single and multiple doses of CB03 in healthy adults, with all dosing expected to finish before the year’s end.

“The orphan drug designation by U.S. FDA for CB03 is an important milestone in its global clinical development for ALS and other central nervous system diseases,” Huanming Chen, PhD, Zhimeng’s president and CEO, said in a company press release.

“Since ALS is a very serious disease without adequate treatment options, we hope our dedicated efforts will allow us to bring a safer and more effective medicine to ALS patients worldwide as the first indication for CB03,” Chen added.

ALS is a neurological disease that damages motor neurons, the nerve cells that control voluntary movements, causing the loss of muscle control. While exact disease causes are unknown, several genetic and environmental factors and lifestyle habits are viewed as increasing its risk.

Neuronal hyperexcitability — the increased likelihood that a neuron will be activated by a certain stimulus — also can be damaging to nerve cells, and it is thought to play an important role in neurodegenerative diseases such as ALS. Potassium channel proteins, which regulate the passage of potassium ions, are important modulators of neuronal excitability.

CB03 is a next-generation small molecule that selectively opens potassium channels called KCNQ2/3. It demonstrated better stability and higher biological or pharmacological activity in lab dish and in ALS animal models than earlier molecules with a similar mechanism.

“CB03 is unlikely to present the same safety concerns as other channel openers and warrant further clinical development to demonstrate potential benefits in the ALS patient population,” Zhimeng stated in its release.