Noxopharm Ltd (ASX:NOX) has reported new preclinical pharmacokinetic data showing that SOF-16, the active ingredient in its cutaneous lupus candidate SOF-SKN, remains in the skin for about 3.5 days in both normal and disease-like skin.
The study examined the highest dose used in the company’s Phase 1 HERACLES safety trial and was designed to help define how often the drug may need to be administered in future studies and, ultimately, in patients.
That half-life matters because it suggests the drug may not need to be applied every day to maintain therapeutic levels in the target tissue. For a chronic inflammatory skin disease such as cutaneous lupus erythematosus (CLE), that could translate into a more practical dosing schedule and better patient adherence if the profile is confirmed in human studies.
The chart included in the announcement shows dermis concentrations remaining broadly consistent across the 7-day observation period in both skin types, supporting the view that the compound is retained for a sustained period after dosing.
Data suggests drug is staying where it is meant to act
The second key finding from the study was distribution. Noxopharm said SOF-16 remained almost entirely within the epidermis and dermis, the layers of the skin where the drug is intended to work. Absorption into the bloodstream was below quantifiable levels at all measured time points.
That is important from both an efficacy and safety perspective. A topical drug designed to stay localised in diseased skin has a better chance of suppressing inflammation at the site of disease while limiting broader systemic exposure. In practical terms, the data supports Noxopharm’s claim that SOF-SKN has been formulated to act in the skin rather than circulate more widely through the body.
For investors, the result does not prove efficacy, but it does reduce one layer of development risk by showing the candidate appears to behave in line with its design in an animal model. That gives the company a stronger pharmacokinetic rationale as it prepares for the next stage of development.
Focus shifts to trial preparation and regulatory package
Noxopharm said the data will form part of the package for regulatory authorities as SOF-SKN advances, and the company is now engaging a contract research organisation to support preparations for a human trial.
SOF-SKN is initially being developed for CLE, which Noxopharm said represents a market worth more than US$3.3 billion, before possible expansion into other autoimmune-related skin diseases including psoriasis and dermatomyositis.
The immediate next step is translating these pharmacokinetic findings into a proposed dosing regimen for human studies. From here, the market is likely to watch for updates on CRO appointment, regulatory submissions and the design and timing of the next clinical trial.