FDA Denies Accelerated Approval for ALS Drug

The US Food and Drug Administration (FDA) has rejected a request for accelerated approval of CNM-Au8, an experimental drug for amyotrophic lateral sclerosis (ALS), drug manufacturer Clene Nanomedicine announced today.

The agency determined that initial data from the company’s phase 2 clinical trial program offered insufficient evidence of reduction of neurofilament light chain (NfL), a key biomarker of neurodegeneration.

CNM-Au8 is composed of catalytically active gold nanocrystals that cross the blood-brain barrier and targets brain cell energy production to promote remyelination. The company says that CNM-Au8 is not associated with toxicities common with other synthetic gold compounds.

As previously reported by Medscape Medical News, the drug failed to achieve the phase 2 RESCUE-ALS trial’s primary outcome of a change in the summated motor unit index (MUNIX) at 36 weeks. However, the company said the drug was safe and reported significant efficacy at 12 weeks.

In a separate statement released today, the company reported results from a 12-month open-label extension of the treatment arm in the HEALEY ALS Platform Trial. Investigators found a 16% decrease in plasma NfL compared to placebo after 76 weeks of treatment. The treatment group also had a 60% lower risk for long-term mortality, the company reported. The results have not been peer reviewed.

The drug is also under investigation for Parkinson’s disease and multiple sclerosis.

The FDA did not release a statement on Clene’s approval rejection. An FDA spokesperson said that the agency is “generally unable to discuss existing or potential applications. That is confidential commercial information.”

The company plans to provide additional data to the FDA early in 2024, the statement said.

Kelli Whitlock Burton is a reporter for Medscape Medical News covering neurology and psychiatry.