20 August 2025 | Sydney, Australia – LTR Pharma Limited (ASX:LTP) is pleased to announce a peer-reviewed publication of clinical data from its Phase I pharmacokinetic study of SPONTAN®, the Company's flagship intranasal formulation for erectile dysfunction (ED). The data has been published in the European Journal of Pharmaceutical Sciences, which is a highly regarded international journal known for rigorous scientific review.
Highlights:
Clinical data has been published in the European Journal of Pharmaceutical Sciences, a leading international peer-reviewed journal.
SPONTAN® demonstrated a median onset of 10 minutes, which is up to 5x faster than conventional oral ED tablet treatments (45 minutes median onset).
Higher bioavailability per milligram reported for SPONTAN, despite using half the dose (compared to oral tablets).
Study confirms comparable therapeutic duration, with both SPONTAN and oral vardenafil showing a half-life of approximately 4 hours.
No serious adverse events reported, with a safety profile consistent with the broader PDE5 inhibitor class.
Supports dual-commercialisation strategy for LTR's intranasal ED products (SPONTAN® and ROXUS®).
Regulatory submissions are underway for the U.S. via the 505(b)(2) pathway, whilst SPONTAN is currently available in Australia via the TGA's Special Access Scheme.
The study confirmed that SPONTAN achieves peak plasma concentrations in a median onset time of just 10 minutes, which is five times faster than conventional oral tablets, which have a median Tmax of 45 minutes. This ultra-rapid onset is seen as a potential breakthrough in ED treatment, addressing the key barrier of spontaneity that leads many patients to discontinue oral medications.
The publication represents significant third-party validation of SPONTAN's differentiated pharmacokinetic profile, strengthening LTR's regulatory dossier as it progresses towards commercialisation in global markets.
Professor Geoff Strange, Chief Medical Officer, LTR Pharma, said: "This peer-reviewed publication in a leading European journal provides robust scientific validation of SPONTAN's game-changing pharmacokinetic profile. The data clearly demonstrate that our intranasal delivery technology achieves the desired therapeutic levels in under 10 minutes – addressing the spontaneity challenge that drives part of the 50% of patients discontinuing oral ED treatments within their first year. From a clinical perspective, this represents a fundamental advancement in how PDE5 inhibitors can be administered, with the potential to significantly improve treatment adherence and patient satisfaction."
The study authors concluded that "intranasally delivered vardenafil is associated with more rapid onset of action with similar plasma concentrations" and that "this differential pharmacokinetic profile has potentially important clinical implications given the overall safety and efficacy profile of PDE5 inhibitors in the treatment of ED, especially in men seeking sexual spontaneity."
Key Clinical Findings:
Ultra-rapid onset: SPONTAN reached peak plasma concentration (Tmax) in a median of 10 minutes (range 9-15 min; mean 12 min) versus oral tablets at a median of 45 minutes (range 30-150 min; mean 56 min), based on the same study data.
Superior efficiency: Despite half the dose, SPONTAN achieved higher bioavailability per milligram, with dose-normalised Cmax of 2.58 ng/mL/mg versus 1.67 ng/mL/mg for oral administration.
Comparable duration: Similar half-life of approximately 4 hours for both formulations, supporting sustained therapeutic effect.
Manageable tolerability: Safety profile consistent with the PDE5 inhibitor class, with no serious adverse events reported.
The data also support LTR's broader intranasal platform, which includes a second ED product, ROXUS®, which is built on the same rapid-onset delivery technology. Both products are designed to address unmet needs in the estimated US$3.7 billion global ED market, where 50% of patients discontinue oral PDE5 treatments due to factors such as delayed onset, food interference, and lack of spontaneity.
The full publication
