Noxopharm (ASX:NOX) said the US Food and Drug Administration has provided constructive feedback that was supportive of its planned approach for a phase II clinical trial for SOF-SKN, its autoimmune disease drug candidate, according to a Thursday Australian bourse filing.

The company said the feedback provides increased regulatory clarity, and helps de-risk the drug candidate's development pathway, while it will incorporate the feedback into preparations for a future investigational new drug (IND) submission that has the potential to increase SOF-SKN's commercial attractiveness.

The phase II trial is targeted for the first half of calendar 2028, subject to regulatory, clinical and manufacturing requirements, it said.

The company said an orphan drug designation opportunity exists for SOF-SKN, given there are no current targeted therapies.

The company's shares fell nearly 2% in recent Thursday trade.