INOVIQ Limited announced positive results from an independent retrospective case-control study to evaluate the performance of its SubB2M-CA15.3 breast cancer test across all stages of breast cancer. CA15.3 is a tumour marker test that is commonly used in a clinical setting to monitor breast cancer treatment response and disease recurrence. By enhancing existing tumour marker tests with SubB2M, sensitivity, specificity and clinical utility are expected to be improved.

The objective of this 94-serum sample study was firstly, to establish that INOVIQ's SubB2M-CA15.3 test effectively discriminates between breast cancer cases and control samples, and secondly, to compare the performance of the SubB2M-CA15.3 test against Roche's Elecsys® CA15.3 II test running in a clinical service laboratory. The data showed INOVIQ's SubB2M-CA15.3 test clearly discriminated between breast cancer and healthy controls across all cancer stages, correctly identifying 73% (69/94) of all samples tested. When compared to Roche's Elecsys® CA15.3 II test, performed on the same set of samples, INOVIQ's SubB2M-CA15.3 test displayed superior performance with: AUC2 of 0.81 vs 0.68; lower false positive rate (21% vs 29%); and lower false negative rate (31.3% vs 43.8%).

The overall performance of INOVIQ's test was 69% sensitivity and 78% specificity for breast cancer across all stages, compared to 56% sensitivity and 71% specificity for the Roche test. Notably, INOVIQ's test discriminated early-stage breast cancer (Stage I and II) from healthy controls, whereas the Roche test only discriminated stage IV cancer from controls. Next steps for the SubB2M-CA15.3 test: The next steps in developing the SubB2M-CA15.3 test for commercialisation are: to complete a 500-sample case-control study to evidence the superior performance of the SubB2M-enhanced cancer detection tests over existing, approved and widely used tests; and to complete a monitoring study for treatment response and disease recurrence.

Sample acquisition/collection for these studies is already underway and the SubB2M-CA15.3 test is expected to be launch-ready by a laboratory partner in December 2023. Additionally, the assay development work completed for the SubB2M-CA15.3 test will now be applied to fast-tracking the development and validation of the SubB2M-CA125 test for ovarian cancer monitoring. SubB2M is an engineered protein that preferentially binds to the pan-cancer biomarker Neu5Gc.

INOVIQ is developing SubB2M-enhanced blood tests for multiple uses, including monitoring breast and ovarian cancers, and for a general health panel. SubB2M may enhance the performance of existing tumour marker tests by binding to multiple Neu5Gc sites on the biomarker that amplify the signal and improve sensitivity, and by increasing the cancer specificity to reduce false positives. According to the World Health Organisation, breast cancer is the most common cancer globally, with 2.3m new cases, 685k deaths and 7.8m survivors (5-year prevalence) in 2020.

The global breast cancer diagnostics market was valued at $4.2 billion in 2021. The intended use of the SubB2M breast cancer test is as an aid for monitoring breast cancer in women that have been diagnosed with breast cancer. The American Society of Clinical Oncology (ASCO) 2015 guidelines recommend regular physical examination and mammography for monitoring breast cancer disease progression and recurrence.

Existing blood tests for serum tumour markers (CA15.3, CA 27.29 and CEA) are not sensitive or specific for breast cancer relapse but are suggested for monitoring treatment response of women with metastatic breast cancer or follow-up in symptomatic women. Roche's Elecsys CA15.3 II test is used to monitor breast cancer treatment response and disease recurrence. At 95% specificity, Roche's test has a sensitivity of 7% for stage I, 11% for stage II, 39% for stage III and 78% sensitivity for stage IV disease, and 81% for recurrent disease.

There is a need for faster, more accurate and cost-effective blood tests to improve breast cancer detection and monitoring.