The FDA has granted AbbVie’s potential first-in-class therapy C2N-8E12 orphan drug designation for the treatment of a rare neurodegenerative disorder.

The company has just begun Phase 1 trials of C2N-8E12 (ABBV-8E12) in progressive supranuclear palsy (PSP), which is thought to affect around 20,000 people in the US and 4,000 people in the UK – although these numbers may be underestimates as it is often misdiagnosed as Parkinson’s disease.

The most common symptoms are loss of balance and, in later stages, blurred vision and problems controlling eye movement. There are currently no approved treatments for the condition.

C2N-8E12 targets the tau protein found in “neurofibrillary tangles” in the brains of patients with PSP. It is being co-developed by C2N Diagnostics, who entered into a deal with AbbVie in March 2015.

Such anti-tau antibodies are also being touted as a promising treatment approach for Alzheimer’s disease, and under AbbVie’s deal with C2N the drug will also be explored for use in this area.

“We are encouraged by the preclinical data of anti-tau antibodies and are committed to exploring the potential of this class of molecules," said Jim Sullivan, vice president of pharmaceutical discovery at AbbVie.