Cleo Diagnostics Ltd

Invention:	Ovarian cancer diagnostic
Name:	Cleo
Patents:	1
FDA Approval:	Pending
Pathway:	Class II 510(k)
ASX:	COV

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​THE INVENTION
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Cleo Diagnostics is an Australian company developing a blood test for early-stage detection of ovarian cancer. The test is powered by a proprietary algorithm built around CXCL10, a novel biomarker first discovered at the Hudson Institute of Medical Research. Through an exclusive licence agreement with Hudson, Cleo holds the rights to apply CXCL10 in diagnostic applications. Designed to run on standard pathology equipment from a simple blood draw, the test is readily scalable for widespread clinical use.

THE SCIENCE

When ovarian lesions begin to form, affected cells release the CXCL10 protein as a signal to activate the immune system. This signal is disrupted by DPP4, an enzyme that breaks down CXCL10 and dampens the immune response. As a result, the immune system shows only a limited response during the early stages of ovarian cancer. Because CXCL10 is released at the onset of disease, it provides a valuable biomarker for early detection. The biomarker was first identified by Cleo’s Chief Science Officer, Dr Andrew Stephens.

PRE-SURGICAL TRIAGE
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The company's initial focus is on a test for pre-surgical triage, where women presenting with a pelvic or adnexal mass require surgery to determine whether the condition is benign or malignant. In this area of diagnosis, Cleo is competing with Risk of Malignancy Index (RMI), Risk of Ovarian Malignancy Algorithm (ROMA), and OVA-1.

RMI is one of the earliest and simplest tools. It combines three factors: menopausal status, ultrasound findings (such as bilaterality, multilocularity, solid areas, ascites, and metastases), and the serum biomarker CA-125. The RMI is calculated as a product of these factors, producing a score that helps stratify patients into low- or high-risk categories for malignancy. Because it relies heavily on CA-125 and imaging, its performance can be limited in premenopausal women (where benign conditions like endometriosis can raise CA-125) or in early-stage cancers (which may not elevate CA-125). Its advantages, however, are ease of calculation, use of widely available inputs, and validation in multiple settings.

ROMA is a more recent algorithm designed to address some limitations of RMI, particularly around premenopausal patients. ROMA combines CA-125 with another biomarker, HE4 (human epididymis protein 4), and incorporates menopausal status into a logistic regression model to generate a “predictive index.” Studies suggest ROMA improves sensitivity compared with CA-125 alone and may perform better than RMI in distinguishing benign from malignant masses, especially in premenopausal women. However, its use is limited by the availability of HE4 testing and variability across populations.

OVA-1 takes yet another approach. It is a multivariate index assay that integrates five biomarkers (CA-125, β2-microglobulin, transferrin, prealbumin, and apolipoprotein A1) through a proprietary algorithm. Unlike RMI and ROMA, OVA-1 is not intended as a general screening or triage test, but rather as an adjunct to guide referral of women with an adnexal mass to a gynecologic oncologist prior to surgery. Its strength lies in very high sensitivity—able to detect malignancies even when CA-125 is normal—but this comes at the cost of lower specificity, leading to more false positives and potentially unnecessary referrals or interventions.

​PERFORMANCE ADVANTAGE

Cleo outperforms ROMA, OVA-1 and RMI as a pre-surgical triage test in both pre- and post-menopausal women:

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TOTAL ADDRESSABLE MARKET

Pre-surgical triage: ~1m
The pre-surgical triage setting offers a relatively clear regulatory pathway and fits into existing diagnostic workflows. The company estimates this market involves approximately one million women, representing the company’s first revenue opportunity.

Recurrence monitoring: ~1.2m
Beyond this, Cleo sees significant potential in the recurrence monitoring market, where patients who have undergone treatment for ovarian cancer are tested regularly to detect relapse at an early stage. This is a mid-term opportunity that could translate into around 1.2 million tests annually.
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Screening: ~148m
In the longer term, Cleo’s vision is to move into population screening for asymptomatic women, a market that could encompass more than 148 million women globally. 

INTELLECTUAL PROPERTY

Cleo Diagnostics holds exclusive rights under the Hudson Licence Agreement, which grants the company access to the CXCL10 biomarker technology developed at the Hudson Institute of Medical Research. As part of this licence, Cleo has patent applications pending in multiple jurisdictions, stemming from the international application PCT/AU2020/051403. To strengthen and protect its position, the company has engaged specialist IP law firm FB Rice to implement a comprehensive intellectual property strategy, with the aim of securing robust protection in key markets and ensuring the ability to enforce its rights if required.

REGULATORY TIMELINE

2025

Q4
510(k) (Pre-Surgical Diagnostic) Readout (n=500)

SOURCES

Cleo Diagnostics Annual Report 2025: https://api.investi.com.au/api/announcements/cov/92595926-cce.pdf

Cleo Diagnostics Corporate Presentation June 2025: https://api.investi.com.au/api/announcements/cov/6a2b522e-507.pdf

​Davenport, et al. Menopausal status, ultrasound and biomarker tests in combination for the diagnosis of ovarian cancer in symptomatic women: https://pubmed.ncbi.nlm.nih.gov/35879201/
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Bristow, et al. Ovarian malignancy risk stratification of the adnexal mass using a multivariate index assay: https://pubmed.ncbi.nlm.nih.gov/23178277/

Fritsche, et al. A reflex testing protocol using two multivariate index assays improves the risk assessment for ovarian cancer in patients with an adnexal mass​: https://pubmed.ncbi.nlm.nih.gov/36820488/
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Stephens, et al. ​A Novel Predictive Multi-Marker Test for the Pre-Surgical Identification of Ovarian Cancer​: https://pubmed.ncbi.nlm.nih.gov/37958440/