More than 300,000 women are diagnosed with ovarian cancer globally each year, a statistic that underscores the urgent need for effective treatments. A recent four-year clinical trial, known as SOLACE2, conducted across 15 Australian hospitals, has brought new hope by evaluating a promising blood test that could revolutionize treatment protocols. This trial was co-led by the University of Sydney NHMRC Clinical Trials Centre, RMIT University, and WEHI, and coordinated by the Australia New Zealand Gynaecological Oncology Group (ANZGOG).
The Phase II trial explored strategies to enhance the effectiveness of PARP inhibitor therapy, a treatment that prevents cancer cells from repairing their damaged DNA. During this trial, a new companion blood test for women with ovarian cancer was evaluated, showing promising results that could lead to more precise treatment options.
Precision Targeting in Cancer Treatment
PARP inhibitor therapy is typically offered to women whose cancer exhibits a defect in DNA repair, known as homologous recombination deficiency (HRD). However, inconsistencies in treatment responses have been observed, with some HRD-negative patients benefiting from the therapy while some HRD-positive patients do not. This suggests that other factors may influence treatment efficacy.
According to Distinguished Professor Magdalena Plebanski, lead researcher at RMIT, there had been no straightforward method to better target PARP inhibitor therapy until now. “In SOLACE2, we demonstrated that a new immune test could better indicate which women will respond to PARP inhibitors,” Plebanski stated. This new test measures immune biomarkers that indicate the movement of cancer-destroying immune cells towards cancer cells, providing a simple ‘biomarker signature’ in blood.
“We expect this promising new test will enable more effective screening and identification of eligible patients for PARP inhibitors, allowing us to provide this leading treatment to the women most likely to benefit.” — Professor Magdalena Plebanski
Understanding the New Blood Test
The new test, which was detailed in Nature Communications, uses RMIT-patented biomarkers that can be easily identified through a simple blood test. This method may offer a better guide to selecting patients who will benefit from PARP inhibitor therapy compared to the current HRD test. The HRD test requires complex analysis of DNA repair, which is not always feasible or accurate as the cancer’s DNA repair capability can change over time.
Professor Clare Scott AM, a lead researcher from WEHI, highlighted the importance of immune cells in the cancer’s response to PARP inhibitor therapy, especially in combination therapies. “A clear indication of who would respond to treatment came from predicting whether effector T cells could increase their migration into the tumor,” Scott explained.
“Now that we understand this is a vital factor for cancer control, we could also potentially improve treatments by focusing on promoting this beneficial migration of immune cells in the future.” — Professor Clare Scott AM
Future Implications and Next Steps
While the new test is not yet available for patients, further testing and confirmation are required before it can obtain necessary approvals for routine use. Professor Chee Khoon Lee, clinical lead at the University of Sydney’s NHMRC Clinical Trials Centre, noted that the SOLACE2 trial showed that three months of immune priming could help delay ovarian cancer recurrence when followed by PARP inhibitor and immunotherapy treatment.
Despite the promising results, the small trial size means that more work is needed for definitive clinical validation. However, the study successfully revealed a new test with the potential to transform treatment outcomes for many women diagnosed with ovarian cancer.
“Our study did successfully reveal this new test that has the potential to transform outcomes for many women diagnosed with ovarian cancer, helping clinicians to better personalize treatments, ensuring each woman receives the most effective therapy for her.” — Professor Chee Khoon Lee
The study, published in Nature Communications and supported by ANZGOG and AstraZeneca, marks a significant step forward in ovarian cancer treatment, offering hope for more personalized and effective therapies in the future.
