PharmAust eyes FDA orphan drug designation for monepantel after positive MND/ALS trial results

Biotechnology company PharmAust (ASX: PAA) has filed supplementary positive data from a Phase 1 MEND trial of lead drug monepantel with the US Food and Drug Administration’s (FDA) Office of Orphan Products Development.

The data was packaged as a formal amendment to an orphan drug designation request submitted in November for monepantel in the treatment of motor neurone disease (MND) and amyotrophic lateral sclerosis (ALS).

It showed that monepantel had the potential to delay the progression of MND and ALS in 12 patients who were subject to daily administration of the drug over a seven to 12-month period.

The drug was found to be well-tolerated and did not result in any dose-limiting toxicities or serious adverse effects.

Quality of life and cognitive and behavioural function were also not significantly impacted and there was no change in patient respiratory function.

Daily dosing resulted in a “clinically meaningful” therapeutic effect as evidenced by a small and non-significant numerical reduction in ALS functional rating scale-revised (ALSFRS-R) scores from baseline to end of treatment.

Clinical trial failures

Two recent clinical trial failures by leading FDA-approved drugs have highlighted a significant unmet global need for safe and effective MND and ALS treatments.

A Phase 3 trial of Relyvrio by US-based Amylyx Pharmaceuticals did not meet its primary or secondary endpoints of reaching statistical significance as measured by a change from baseline in the ALSFRS-R total score at week 48.

Amylyx will now engage with regulatory authorities on the future of the drug, which may include voluntary withdrawal from the market.

A Phase 3 study of edaravone by Ferrier International SA also did not show significant benefit over placebo in patients with ALS in slowing disease progression as measured by change from baseline in the ALSFRS-R score at week 48.

No improvement over placebo on long-term survival was observed over 48- and 72-week periods for a subgroup of patients.

Edaravone is currently approved by the FDA for intravenous and oral administration and distributed by Mitsubishi Tanabe Pharma.

Company confidence

PharmAust chief executive officer Dr Michael Thurn was confident that monepantel would be more successful.

“Based on the strength of our Phase 1 outcomes, we are very confident that monepantel will be granted an orphan drug designation for the treatment of MND and ALS,” he said.

“Receiving this status will come at a good time for us given the recent clinical trial failures of the two leading FDA drugs for MND/ALS… monepantel offers much needed hope for patients with this severely debilitating disease.”

PharmAust is expecting a response from the FDA within 90 days.

Meanwhile, the company remains on track to commence a pivotal registration Phase 2/3 study for MND and ALS before mid-year.