FDA confirms Phase III pathway for Female Testosterone MDTS
Following formalisation of its end-of-Phase II meeting minutes, the U.S. Food and Drug Administration (FDA) has confirmed the clinical Phase III regulatory pathway for Female Testosterone metered-dose transdermal spray (MDTS) at Acrux Limited (ASX:ACR). The product targets postmenopausal women with hypoactive sexual desire disorder (HSDD).
The FDA also confirmed that Acrux will be eligible to apply for a 3-year exclusivity period when the company makes its submission. Acrux stated it now has greater clarity on the Phase III pathway and “increased confidence in being the first female testosterone product for women in the US market.” That confidence is the company’s own view, not a confirmed outcome.
An investor webinar was scheduled for 3pm AEDT on 12 October 2026. Regulatory clarity of this kind may reduce development uncertainty ahead of Phase III.
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Phase III trial design: what the FDA confirmed
The FDA feedback covers trial structure, endpoints, formulation status and safety requirements. The table below summarises the outcomes and what each may mean for investors.
| FDA outcome | Detail | Investor implication |
|---|---|---|
| Efficacy trials | Two adequate and well-controlled 24-week Phase III trials | Defines the efficacy evidence required to support approval |
| Safety data | Additional 28 weeks of data (52 weeks total) | Sets the safety dataset for chronic treatment |
| Trial design | Trials need not be identical | Provides flexibility as designs are finalised |
| Formulation | Testosterone MDTS considered a new formulation | Underpins eligibility to apply for exclusivity |
Two 24-week trials
The FDA confirmed that two adequate and well-controlled 24-week Phase III trials will demonstrate reproducible efficacy for HSDD in postmenopausal women and support approval. An additional 28 weeks of data, for a total of 52 weeks, will inform safety for chronic treatment.
Design flexibility
The FDA advised that the two trials need not be identical in design, for example in timing intervals. The feedback was in line with standard FDA guidance.
Other outcomes from the meeting include:
- The FDA provided alternative approaches to patient reported outcome co-primary endpoints, in line with the 2016 FDA draft Guidance, so Acrux can select the most appropriate endpoints for the trial.
- The FDA acknowledged that testosterone MDTS should be considered a new formulation.
- A chronic dermal and systemic safety study would be in line with FDA guidelines, and Acrux is finalising the protocol.
John Warmbrunn, CEO
“The guidance provides greater clarity on our regulatory pathway…”
How data exclusivity works and why it matters
Data exclusivity is a period during which a regulator limits competitors from relying on a sponsor’s new clinical data. According to the announcement, the FDA offers 3 years of data exclusivity for the first approval of an established active ingredient for a new indication for an established drug, when new clinical studies support the application.
The agency confirmed that Acrux’s Phase III trials and new formulation meet this requirement. The company will therefore be eligible to apply for a three-year exclusivity period at the time of submission.
This is eligibility to apply only. Exclusivity has not been granted.
If granted, the announcement states exclusivity significantly increases Acrux’s commercial opportunity by preventing the launch of competitor products for the first three years after registration. The FDA also recommended a minimal preclinical package of chronic dermal and systemic safety.
FDA workshop signals unmet need and partnering interest
In September, the FDA held a public workshop examining testosterone use in menopausal women. Topics included the current treatment gap, the need for female-specific dosing and formulation, and the evidence required to support future product development.
Key themes from the workshop were:
- Significant unmet need for an FDA-approved testosterone treatment specifically developed for women.
- The importance of controlled female-appropriate dosing and maintaining testosterone within the physiological range.
- FDA openness to engage with sponsors on evidence-based product development.
Mr Warmbrunn said these themes align closely with the guidance received, describing Female Testosterone MDTS as “wonderfully aligned with these objectives.” He added that these regulatory and market signals are also “supporting constructive discussions with potential co-development partners as we progress Female Testosterone MDTS into Phase III development.” The announcement does not disclose any agreement, term sheet or named partner.
Felicia Colagrande, Product Development and Technical Affairs Director
“It is exciting to see Acrux’s long-standing expertise in transdermal drug delivery being applied to such an important area of unmet need in women’s health…”
Ms Colagrande has worked at Acrux for 25 years since its spin out from Monash University.
Next steps for investors
Acrux is finalising the protocol for the chronic dermal and systemic safety study, as well as the Phase III trial designs. The company is also progressing Female Testosterone MDTS into Phase III development while holding discussions with potential co-development partners.
Phase III execution will sit with Acrux’s newly appointed Chief Medical Officer, Dr Jolanta Airey, who previously served as Medical Monitor on the trials that launched the company’s male testosterone product Axiron.
The announcement does not disclose Phase III start dates, costs, funding or approval timelines.
The webinar was also set to cover key themes from the FDA workshop, followed by an investor Q&A. Investors can sign up to the Acrux InvestorHub for company news.
Acrux is a specialty pharma company drawing on 25 years of experience, which has marketed products through licensees worldwide with emphasis on the United States.
Investors exploring the broader investment case can read our full explainer on Acrux’s Female Testosterone strategy, which covers the Phase I and II results, the self-funding Topical Generics revenue base and the targeted launch timeline.
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