LTR Pharma has completed the final Phase II pharmacokinetic report for SPONTAN, confirming a median 10-minute time to peak concentration against 60 minutes for an oral vardenafil tablet. The result completes the FDA-aligned dataset ahead of planned US submission work, although efficacy in erectile dysfunction patients remains to be tested.
- Median 10-minute peak concentration for SPONTAN 5 mg versus 60 minutes for oral vardenafil
- Final pharmacokinetic dataset completed for planned US 505(b)(2) submission
- No drug accumulation after five days of once-daily dosing
- Comparable pharmacokinetics in participants aged 65 and over
- No serious adverse events, Grade 3 or higher events or discontinuations
SPONTAN Confirms Rapid Absorption
LTR Pharma Limited (ASX:LTP) has completed the final Phase II pharmacokinetic report for SPONTAN, with the intranasal treatment reaching peak blood concentration in a median 10 minutes at the 5 mg dose. That compares with 60 minutes for a 20 mg oral vardenafil tablet, a difference the company says was statistically significant at p<0.0001.
The result confirms the interim findings announced in May and completes the pharmacokinetic dataset agreed with the US Food and Drug Administration for a planned 505(b)(2) submission. The report was prepared by independent clinical research organisation Southern Star Research, giving LTR a defined evidence package for further regulatory engagement and licensing discussions.
Dose Response and Older Participants
SPONTAN’s 2.5 mg dose produced a median time to peak concentration of 11 minutes, while the 5 mg dose produced 10 minutes. Exposure broadly tracked the dose: the lower-dose product generated approximately half the exposure of the 5 mg dose, while the 5 mg dose produced roughly one-quarter of the total exposure of the 20 mg oral tablet.
The study also found no drug accumulation after five days of once-daily 5 mg dosing. Pharmacokinetics were comparable between participants aged 65 and over and younger adults, an important part of the FDA-aligned design because oral PDE5 inhibitors can require dose adjustment in older men. The major metabolite showed substantially lower exposure with SPONTAN than with the oral tablet, consistent with intranasal delivery avoiding first-pass metabolism.
Safety Results Remain Favourable
All 27 healthy adult male participants completed the study, including 14 aged 65 and over. The randomised, open-label, three-way crossover design compared single doses of SPONTAN with the oral tablet before assessing five days of once-daily SPONTAN 5 mg dosing.
No serious adverse events, Grade 3 or higher treatment-emergent adverse events, treatment discontinuations or withdrawals were reported. Treatment-related events were mainly mild and self-resolving, with nasal congestion and headache among the most common. These findings support the product’s tolerability in this small healthy-volunteer study, but they do not establish clinical efficacy in men with erectile dysfunction.
Phase III and US Submission Work Ahead
LTR now plans to move into submission-enabling workstreams in the second half of calendar 2026, including CMC package finalisation, human factors validation, leachables assessment and non-clinical toxicology. A pivotal Phase III study is targeted to begin in the first half of calendar 2027, followed by the planned 505(b)(2) submission.
Chief Medical Officer Professor Geoffrey Strange said the final report provided a “complete, well-characterised pharmacokinetic picture”, while Executive Chairman Lee Rodne said the company’s focus was moving from the completed dataset towards Phase III preparation, regulatory work and potential licensing outcomes. Those remain targets rather than approvals, commercial agreements or evidence of effectiveness in the intended patient population. The next test is whether LTR can convert a persuasive absorption profile into the larger clinical, manufacturing and regulatory package required for market access.
Bottom Line?
The pharmacokinetic hurdle has been cleared, but SPONTAN still needs Phase III efficacy data, submission-enabling work and a regulatory decision before its rapid onset can become a commercial outcome.
Questions in the middle?
- Will the planned Phase III study start in the first half of calendar 2027?
- Can SPONTAN demonstrate meaningful clinical benefit in erectile dysfunction patients, beyond rapid absorption in healthy volunteers?
- Will the completed dataset lead to a US licensing agreement or other commercial partnership terms?