"Companion diagnostics…ovarian cancer diagnostic paradigm shift"

Manager of the Pathology Diagnostics Division at Roche Diagnostics Korea

Platinum-resistant ovarian cancer…precision medicine rises in the field of treatment void

Patient selection based on FRα…key variable to determining treatment effectiveness

Roche, increasing domestic presence based on its diagnostics

A shift in the treatment paradigm for platinum-resistant ovarian cancer, a field with historically limited options, is anticipated following the arrival of antibody-drug conjugate (ADC) therapies.

Notably, the introduction of new treatments has highlighted the growing importance of companion diagnostics in determining 'which patients should receive the therapy?'

Daily Pharm met with Min Ae Baek, Manager of the Pathology Diagnostics Division at Roche Diagnostics Korea, to discuss the significance of companion diagnostics in ovarian cancer, practical clinical application, and the substantial value to patients.

Platinum-resistant ovarian cancer, a disease without alternative options…addressing treatments and diagnostics altogether

Ovarian cancer is classified as a high-risk malignancy due to the difficulty of early detection and high recurrence rates. Most patients are diagnosed at advanced stages and frequently experience recurrence even after standard therapy. 

Platinum-resistant ovarian cancer, which recurs within six months of platinum-based chemotherapy, poses a particularly restrictive environment due to low response rates to conventional therapies and poor prognosis.

Manager of the Pathology Diagnostics Division at Roche Diagnostics Korea

Baek identified the 'treatment void' as the primary unmet need in platinum-resistant ovarian cancer. 

Baek explained, "Reaching the platinum-resistant stage effectively leaves patients with no viable alternatives. As response rates to existing drugs decrease and life expectancy drops to approximately one year, both patients and guardians find themselves in a desperate situation," she explained.

Baek said, "Most patients with ovarian cancer are diagnosed at stage 3-4, and in many cases, patients experience relapses; the majority of patients reach these stages."

The recently introduced targeted therapy, Elahere (mirvetuximab soravtansine), and its companion diagnostic are viewed as pivotal elements that could alter the current treatment landscape.

Baek said, "The emergence of a new option in an area where alternatives were non-existent, coupled with a test to screen for patients who can benefit from it, represents a significant evolution."

Treatment success is dependent on patient selection…the significance of companion diagnostics

The oncology paradigm is rapidly evolving. Previously, treatment relied on broad application. Currently, it is moving toward precision medicine based on specific biomarkers. 

In this transition, companion diagnostics function as the starting point of the treatment strategy.

​"The core value of companion diagnostics lies in selecting the appropriate patient group, thereby simultaneously enhancing treatment efficiency and safety," Baek stated. "Identifying suitable patients through testing reduces the burden of side effects and costs associated with unnecessary treatments while increasing the efficiency of the clinical decision-making process."

Baek's view is that these trajectories not only help medical professionals to make decisions but also directly impact patients.

At the center of this shift is the biomarker folate receptor alpha (FRα). As a protein highly expressed on ovarian cancer cells, FRα has gained clinical utility as a target for ADC therapies. 

Baek explained, "Ovarian cancers require folate for proliferation and overexpress these receptors to absorb folate for proliferation. This characteristic is utilized for targeted anticancer strategies."

The VENTANA FOLR1 (FOLR1-2.1) RxDx Assay plays a crucial role here. This immunohistochemistry (IHC)-based companion diagnostic assesses FRα expression in tumor tissue to identify eligible patients. 

Baek mentioned, "This approach is a dye-based assay, where FRα protein expression is checked, and pathologists confirm these under a microscope," and "It does not simply check for presence but evaluates expression levels against criteria to determine if treatment is applicable."

The value of diagnostic-led therapy has been substantiated in clinical studies such as the Phase 2 SORAYA and Phase 3 MIRASOL trials. 

Baek stated, "The SORAYA study provided initial evidence showing a meaningful objective response rate for Elahere monotherapy," and added, "In the MIRASOL study, superior therapeutic effects compared to conventional chemotherapy were confirmed when treatment was applied after selecting patients with high FRα expression.

Specifically, in clinical trials, Elahere has been shown to improve major clinical indicators compared to existing treatments. Significant improvements in progression-free survival and objective response rate have been reported, along with a reduction in the risk of disease progression or death.

Current guidelines from the Korean Society of Gynecologic Oncology (KSGO) already recommend Elahere for FRα-positive platinum-resistant ovarian cancer with the highest level of evidence (Level I) and recommendation grade (Grade A).

Domestic launch imminent in May..."Will help in deciding treatment options"

In Korea, the treatment environment based on companion diagnostics is also entering the full-scale introduction stage.

Both Elahere and Roche Diagnostics Korea's companion diagnostic (VENTANA FOLR1 (FOLR1-2.1) RxDx Assay) have already received approval from the Ministry of Food and Drug Safety, and clinical use is expected once test supplies begin.

Baek said, "To prescribe medicines, assays must be available. Assays will be supplied in Korea starting this May," and added, "Pathological divisions in Korea already have an established platform to deliver these assays. The view is that it will be effectively implemented, considering the established diagnostics infrastructure."

Baek also mentioned, "There have been continuous inquiries from the field regarding the ability to provide new treatment options to patients with platinum-resistant ovarian cancer," and conveyed, "As it is a test that already has high awareness among medical staff and has been awaited for introduction, expectations are also high from patients."

As the treatment and companion diagnostic are ahead of their launch, there is an opinion in the clinical field that it is necessary to preemptively establish treatment plans by performing the FRα test during the initial diagnosis stage rather than at the stage of treatment use.

Regarding this, Baek projected that if the test is conducted within the approved criteria, it could help consider future treatment options.

Baek stated, "The current approval criteria allow for testing on specimens from patients diagnosed with high-grade serous epithelial ovarian cancer, fallopian tube cancer, or primary peritoneal cancer," and noted, "Checking each patient's information in advance could assist medical staff in establishing treatment plans."

Ultimately, as the expansion of companion diagnostics leads beyond simple technology introduction to a change in the treatment structure, the role of Roche Diagnostics Korea is also expanding.

The company is focusing on more than just supplying testing products. It is building an environment where pathology medical staff can perform tests reliably and support the smooth implementation of companion diagnostic-based treatment.

Baek added, "As companion diagnostics are a critical area directly linked to treatment, it is important to ensure that patients are appropriately selected through standardized tests in a stable environment and that the results lead to treatment," and added, "We will continue to prepare the foundation so that companion diagnostics can be implemented in the medical field in line with the trend of emerging new biomarkers and treatments."