Mercy BioAnalytics presented data on the performance of its Mercy Halo Ovarian Cancer screening test in a large cohort of asymptomatic, postmenopausal women. The company is developing a highly sensitive and specific screening test designed to detect ovarian cancer earlier in this population.

The analysis included samples from the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS), which enrolled 200,000 women randomized to either no screening or annual screening, and followed them for up to 20 years. All trial participants donated a blood sample at enrollment. Mercy analyzed the blood samples of over 1,300 trial participants to assess the sensitivity and specificity of the Mercy Halo test for detecting ovarian cancer up to three years before clinical diagnosis.

Key Findings:

• The sensitivity 0-12 months before the diagnosis of HGSC of the EV-based blood test was 82% and CA125 at a cut-off of 15.5 U/mL was 63%. 

• The specificity in controls, of the EV-based blood test was 97.7%, and of CA125 was 95.5%. 

• The area under the concentration-time curve (AUC) 0-12 months before the diagnosis of the EV-based blood test was 0.94 and 0.87.  

• The EV-based blood test was able to detect HGSC up to 3 years before diagnosis. 

• In samples from women with a false positive transvaginal ultrasound (TVUS FP) who underwent trial surgery in the USS arm and had benign pathology, the specificity of the EV-Blood Test was 97.6%, and of CA125 was 89.5%. 

Conclusion

In conclusion, the  Extracellular Vesicles (EV) based blood test demonstrated highly sensitive and specific detection of early-stage high-grade serous carcinoma in asymptomatic postmenopausal women, surpassing the sensitivity and specificity of CA125 (cut-off 15.5 U/mL). The PROBE design's rigor and the use of the best possible CA125 cut-off for comparison support the potential suitability of the EV-based blood test for ovarian cancer screening. The company plans that future research will concentrate on evaluating the EV-based blood test in samples from ovarian cancer screening trials with longitudinal data.