CAN106 Gets FDA Orphan Drug Designation for Myasthenia Gravis

The therapy blocks the C5 complement protein

Marisa Wexler, MS avatar

by Marisa Wexler, MS |

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CAN106, an investigational complement-inhibiting therapy being developed by CANbridge Pharmaceuticals, has been granted orphan drug designation by the U.S. Food and Drug Administration (FDA) as a potential treatment for myasthenia gravis (MG).

The FDA gives orphan drug status to therapies that have the potential to treat rare disorders, defined as those affecting fewer than 200,000 people in the U.S. The designation gives CANbridge, as the medicine’s developer, certain incentives such as fee waivers and the right to seven years of market exclusivity if the therapy is approved.

“Orphan drug designation for CAN106 in MG is both a validation of CANbridge innovation and a major milestone as our first U.S. FDA regulatory designation,” James Xue, PhD, founder, chairman, and CEO of CANbridge, said in a company press release.

In MG, an autoimmune attack interferes with the communication between nerve and muscle cells, resulting in symptoms such as muscle weakness. Abnormal activation of the complement system, also known as complement cascade, plays a central role in the attack.

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The complement cascade comprises a group of immunological proteins present in the blood and other bodily fluids. Complement proteins are normally inactive, but they become activated in response to inflammation.

Activation takes the form of a series of chemical reactions, sort of like a Rube Goldberg machine or a series of dominoes falling over. One activated complement protein activates another, which activates another, and so forth.

CAN106 is a lab-made, long-acting monoclonal antibody designed to bind to and block a complement protein called C5. When the complement cascade is activated, inactive C5 is split into two active components — C5a and C5b — which trigger inflammatory damage. By neutralizing C5, CAN106 can prevent this split, preventing downstream complement pathways from being activated.

CAN106 doesn’t interfere with the activation of C3, a complement protein made active earlier in the cascade and that’s important for the immune system’s first line of defense against microbes.

A Phase 1b/2 trial (NCT05539248) in China is evaluating CAN106’s safety, tolerability, effectiveness, pharmacokinetics, and pharmacodynamics in people with paroxysmal nocturnal hemoglobinuria (PNH), a complement-mediated autoimmune disease characterized by blood cell destruction. Pharmacokinetics refers to a therapy’s movement into, through, and out of the body. Pharmacodynamics concerns its effects on the body.

So far, the therapy has shown a favorable safety and pharmacological profile, suggesting it “has the potential to effectively inhibit C5 in patients with certain complement-mediated disease,” CANbridge stated in the release.

“We continue to advance our global development strategy for CAN106 and look forward to developing CAN106 for myasthenia gravis and other complement-mediated diseases,” Xue said.