Acrux (ASX: ACR) secures clearer FDA Phase III pathway for female testosterone treatment

Acrux Limited (ASX: ACR), the Melbourne-based pharmaceutical company specialising in transdermal drug delivery technologies, has received formal feedback from the United States Food and Drug Administration establishing a clearer Phase III clinical development pathway for its Female Testosterone Metered Dose Transdermal System. The product is being developed for postmenopausal women with hypoactive sexual desire disorder, a condition associated with persistently reduced sexual desire and related distress. The 12 October 2026 announcement outlines a requirement for two adequate and well-controlled 24-week efficacy trials, together with additional safety observations supporting a total of 52 weeks of exposure data. The regulatory feedback reduces uncertainty about the evidence Acrux must generate, but it is not a product approval, permission to commercialise the treatment or confirmation that the proposed trials will achieve their objectives.

What has the United States FDA confirmed about Acrux’s Female Testosterone MDTS Phase III trials?

The formalised FDA meeting feedback provides Acrux with a more specific framework for its late-stage clinical development programme. The regulator indicated that two adequate and well-controlled 24-week Phase III studies would be required to establish reproducible treatment efficacy in the intended patient population. Additional safety evidence covering 28 weeks beyond the 24-week efficacy assessment would support a total 52-week safety evaluation. The requirements reflect the need to assess both clinical benefit and risks associated with longer-term testosterone exposure.

The two Phase III efficacy studies do not have to be identical in every design element, providing some flexibility as Acrux develops the protocols. The FDA also provided alternative approaches to patient-reported co-primary endpoints, consistent with the agency’s existing guidance for evaluating female sexual dysfunction treatments. Endpoint selection will be important because the studies must demonstrate clinically interpretable benefits under conditions sufficient to support a regulatory application. Acrux is still responsible for finalising study designs that can generate acceptable evidence.

The FDA also addressed preclinical and clinical safety requirements, including chronic dermal and systemic safety assessments. These requirements are relevant because transdermal delivery introduces considerations involving skin exposure, dose consistency and systemic hormone concentrations. Demonstrating that the medicine produces an acceptable safety profile over sustained use will be necessary alongside evidence of efficacy. The company is finalising the protocol for the additional chronic safety work.

The latest feedback follows Acrux’s earlier Phase II development work and regulatory engagement. The company previously reported encouraging efficacy findings from its mid-stage study, including an improvement in the selected 90-microlitre treatment group’s primary endpoint. Those results supported continued clinical development but did not establish the reproducibility or longer-term safety evidence expected from pivotal trials. Phase III will therefore test whether the earlier findings can be confirmed in larger, appropriately controlled populations.

Why is Acrux developing a female-specific testosterone treatment for hypoactive sexual desire disorder?

Female Testosterone MDTS is designed to deliver testosterone through the skin using a metered-dose spray formulation. Acrux is targeting postmenopausal women diagnosed with hypoactive sexual desire disorder, rather than promoting testosterone treatment for all menopausal symptoms or for women without an appropriate clinical diagnosis. The indication involves a specific clinical condition requiring assessment of symptoms, distress and other possible contributing factors. Regulatory approval, if eventually obtained, would be tied to the evidence supporting the proposed patient population and treatment regimen.

The United States does not currently have an FDA-approved systemic testosterone product specifically developed and authorised for women with this indication. That creates a potential commercial opportunity for a treatment capable of demonstrating efficacy, consistent dosing and an acceptable safety profile. However, the absence of an approved female-specific product does not establish that every affected patient would receive testosterone or that clinicians would adopt a new formulation universally. Prescribing decisions would depend on the approved label, professional guidance, patient suitability and reimbursement arrangements.

Acrux has estimated that approximately 4.9 million menopausal women in the United States may be affected by the targeted condition. Such estimates describe a potential patient population rather than the number of individuals who would qualify for treatment or purchase the product. Actual commercial demand would depend on diagnosis rates, physician acceptance, access to specialist care and competing approaches to managing sexual dysfunction. The final regulatory indication would also determine the breadth of the eligible population.

The FDA’s September public workshop examining testosterone use in menopausal women provided additional regulatory context for the programme. Discussions considered the evidence requirements, the importance of female-appropriate dosing and the need to understand longer-term safety. Acrux believes the workshop’s themes support its approach to developing a dedicated female testosterone formulation. The workshop itself did not grant approval or remove the need for controlled clinical trials.

Could Acrux obtain three years of United States regulatory exclusivity for Female Testosterone MDTS?

The FDA has acknowledged that Acrux’s metered-dose transdermal testosterone product may qualify as a new formulation for the relevant regulatory pathway. The company has indicated that this could make the product eligible to apply for three years of regulatory exclusivity if the necessary statutory requirements are satisfied. Such exclusivity would be considered in connection with a future successful registration application supported by the required new clinical investigations. No exclusivity period has been granted at this stage.

Regulatory exclusivity can provide commercial protection by restricting specified reliance on an approved sponsor’s qualifying clinical data for certain competing applications. It should not automatically be equated with patent protection, an absence of competing medicines or a guarantee that no alternative treatment can enter the market. Its exact operation depends on the statutory framework, the approved product and the eligibility determination made by the regulator. Acrux would need to obtain marketing approval and meet the applicable requirements before receiving any corresponding exclusivity.

The possibility of exclusivity is commercially relevant because a newly approved product may require substantial investment in clinician education, distribution and reimbursement access. A defined period of regulatory protection can improve the predictability of early commercialisation for a qualifying product. Nevertheless, protection has economic value only if the medicine gains approval and attracts sufficient demand. The current development stage means both the regulatory outcome and prospective revenue remain uncertain.

Acrux also needs to determine how the formulation’s intellectual property and regulatory advantages fit within its eventual commercial partnership strategy. The product’s potential differentiation could include its delivery format, dose control and evidence generated specifically in women. Those characteristics may support future discussions with pharmaceutical commercialisation partners. Their financial value cannot yet be established because no completed licensing transaction or corresponding commercial terms have been announced for the programme.

How could the FDA’s Phase III requirements affect Acrux’s clinical development costs and financing needs?

Two adequately controlled pivotal efficacy studies and an extended safety database can require substantial clinical expenditure, particularly when recruitment, follow-up and safety monitoring extend over many months. Acrux must finalise trial protocols, determine patient numbers, establish study sites and coordinate the collection of regulatory-quality evidence. The FDA feedback helps define the scope of that work but does not quantify the cost of completing it. The company has not announced a definitive Phase III trial budget, start date or expected submission timeline.

The distinction between regulatory clarity and financial readiness is important for a company of Acrux’s scale. Trial expenditure can be incurred well before a medicine generates commercial revenue, requiring companies to fund development through existing cash, partners or additional capital. A successful regulatory meeting can make the programme easier to evaluate, but it does not automatically finance the next development stage. The ability to secure an appropriate development arrangement will influence how quickly Acrux can move from protocol preparation into patient recruitment.

Acrux recently received approximately A$1.977 million through Australia’s research and development tax incentive programme for FY26. The company used the proceeds to repay principal and interest on a short-term facility with Radium Capital, leaving approximately A$904,656 in net receipts after settlement. This improves the company’s immediate resources relative to the position before the rebate, but the net amount should not be confused with the entire gross tax incentive. The announcement does not establish that the rebate is sufficient to finance the planned pivotal studies.

The company has indicated that discussions with potential co-development and commercialisation partners are continuing. A partnership could potentially distribute future trial costs, technical responsibilities and commercial risks between the parties, depending on its structure. However, no definitive agreement or named counterparty has been disclosed in the latest programme update. Until binding terms are announced, potential partnering interest should not be treated as committed financing or confirmed licensing revenue.

What do Acrux’s Phase II findings establish about the effectiveness of its transdermal testosterone spray?

Acrux’s earlier Phase II programme provided preliminary evidence supporting further investigation of Female Testosterone MDTS. The company reported that testosterone treatment groups showed improvements in measures of satisfactory sexual events compared with placebo, with its selected 90-microlitre dose achieving a statistically significant result for the study’s primary endpoint. Those findings informed selection of the dose and the subsequent regulatory discussions. They do not establish that the treatment has met the evidence requirements for United States marketing approval.

Pivotal clinical trials will need to address reproducibility, clinical relevance and safety in the intended population. The selection of patient-reported outcomes is particularly important because treatment benefit must be demonstrated through meaningful changes in the condition being studied. The FDA’s feedback on possible co-primary endpoint approaches provides flexibility, but Acrux must still choose endpoints and analysis methods capable of supporting a scientifically credible conclusion. Statistical success in one earlier treatment group does not guarantee corresponding results in the larger Phase III programme.

Safety evaluation is another important component of the development programme. Testosterone exposure may require assessment of androgen-related effects, systemic hormone concentrations and other relevant clinical outcomes over time. The FDA’s request for additional longer-term observations reinforces the need for a complete risk-benefit assessment before approval could be considered. The eventual product label, if approved, would depend on the totality of evidence submitted.

Acrux’s experience in transdermal medicines provides technical knowledge relevant to formulation development and dose delivery. The company has previously commercialised testosterone-related technology through pharmaceutical partnerships, including its work associated with the male testosterone product Axiron. Nevertheless, regulatory approval of an earlier male testosterone treatment does not establish the safety, efficacy or approval prospects of a different product intended for women. Female Testosterone MDTS must meet the requirements applicable to its own formulation, clinical indication and supporting evidence.

What commercial milestones could strengthen the outlook for Acrux’s female testosterone programme?

The immediate development priority is to finalise the Phase III study protocols in a form consistent with the formalised FDA feedback. Acrux must also complete planning for the chronic dermal and systemic safety assessments and determine how the trials will be funded and executed. The appointment of experienced clinical personnel, including Chief Medical Officer Jolanta Airey, provides additional management capacity for those activities. A confirmed development timetable would allow investors to assess the expected duration and capital requirements more accurately.

A binding partnership would represent a separate commercial milestone, particularly if it included funding commitments, development cost sharing or defined licensing economics. Any announced agreement would need to be evaluated according to its upfront payments, milestones, royalties, territorial rights and responsibilities rather than headline potential value alone. Without those terms, the existing discussions provide evidence of interest but not independently measurable financial value. Successful recruitment into the pivotal studies would then provide operating evidence that the programme has entered its next stage.

The regulatory feedback gives Acrux a more defined development framework and a possible route toward future market exclusivity. The programme remains subject to the scientific uncertainties of Phase III efficacy testing and extended safety assessment, alongside the financial requirements of execution. The next decisive proof points are finalised pivotal trial designs, committed funding and commencement of appropriately controlled clinical studies. Those developments would establish whether the current regulatory progress can translate into a credible path toward an eventual marketing application.

Key takeaways from Acrux Limited’s FDA feedback on Female Testosterone MDTS

• Acrux has received formalised FDA feedback on the Phase III pathway for Female Testosterone MDTS.
• The product targets hypoactive sexual desire disorder in postmenopausal women.
• Two adequate and well-controlled 24-week efficacy studies are required.
• Additional safety follow-up will support a total of 52 weeks of exposure data.
• The FDA has allowed flexibility in aspects of trial design and patient-reported endpoints.
• Acrux may be eligible to apply for three years of regulatory exclusivity after satisfying the applicable requirements.
• No marketing approval or exclusivity period has been granted.
• Phase III costs, funding arrangements and trial start dates have not been confirmed.
• Acrux continues discussions with potential development and commercialisation partners.
• Final study protocols, financing and initiation of pivotal trials will be the next important milestones.