- 01TMax ~10–11 min vs 60 min for oral vardenafil.
- 025mg Spontan: lower AUC; dose-normalised AUC similar.
- 03No accumulation after 5 days; mild nasal congestion/headache.
A final clinical report for a Phase II pharmacokinetic study on LTR Pharma’s (ASX: LTP) Spontan fast-acting intranasal spray to treat erectile dysfunction (ED) has completed the dataset requirements for a regulatory new drug application and US licencing discussions.
The study at Scientia Clinical Research in Sydney involved 27 healthy adult males (including 14 men aged 65 and over) in a randomised, open-label, three-way crossover design agreed with the US Food and Drug Administration under pre-investigational new drug (IND) guidance.
The clinical report found that Spontan displayed a six-fold faster absorption than oral vardenafil tablets, achieving peak blood concentration in a median 10 minutes (for a 5 milligram dose) and 11 minutes (2.5mg) compared to 60 minutes for a 20mg tablet.
A four-fold lower dose of Spontan 5mg produced approximately four times lower total exposure (known as area under the curve, or AUC) than the 20mg tablet, while doubling the Spontan dose from 2.5mg to 5mg approximately doubled exposure.
Dose-normalised AUC point estimates were broadly comparable across treatments and half-life was generally consistent across both routes, confirming that the principal difference between Spontan and oral vardenafil was in the absorption phase rather than elimination.
Spontan Safety Profile
Exposure to the body’s major metabolite by maximum plasma concentration (Cmax) and AUC was found to be substantially lower for Spontan than for vardenafil, as intranasal delivery avoids first-pass metabolism.
Five days of once-daily dosing showed no drug accumulation and no clear pharmacokinetic differences were observed between younger adults in the study or men aged 65 and over, who made up 14 of the 27 participants.
A safety analysis did not identify any new, unexpected, or serious treatment-emergent adverse events across the study population, nor any treatment discontinuations or study withdrawals.
Reported reactions were predominantly mild and self-resolving, with nasal congestion and headache consistent with the known pharmacology of vardenafil and the intranasal route of administration.
Supporting Interim Results
LTR chief medical officer Professor Geoffrey Strange said the final report supported interim Phase II results in May that demonstrated rapid absorption, repeat-dose behaviour, and a consistent safety profile.
“This report confirms the interim analysis and is consistent with the rapid absorption we demonstrated in our Phase I study,” he said.
“A median time to peak concentration of 10 minutes at a quarter of the oral dose—with no accumulation on repeat dosing and comparable pharmacokinetics in men aged 65 and over—gives us a complete, well-characterised pharmacokinetic picture and strongly supports Spontan’s positioning as a rapid-onset, on-demand therapy.”
Executive chair Lee Rodne added that the complete dataset was the “evidence package that US licencing partners and regulators need to see”.
LTR’s will now progress Spontan’s US development program from preparations for a Phase III study through to a planned 505(b)(2) new drug application submission, while converting partnering discussions into commercial outcomes.
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