Roche has received U.S. Food and Drug Administration (FDA) approval for the VENTANA Ⓡ PTEN (SP218) RxDx Assay, marking the first immunohistochemistry (IHC) companion diagnostic authorized to assess PTEN protein loss in patients with prostate adenocarcinoma.
The assay is intended to identify patients whose tumors exhibit PTEN deficiency, a biomarker associated with disease progression and therapeutic response.
The approval links directly to treatment eligibility with AstraZeneca’s targeted therapy TRUQAP Ⓡ (capivasertib) in combination with abiraterone acetate, offering a new biomarker-driven option for a subset of patients with metastatic hormone-sensitive prostate cancer.
Addressing an unmet need in prostate cancer stratification
In prostate cancer, PTEN functions as a tumor-suppressor protein, and its loss is commonly observed across multiple tumor types. According to the company, PTEN protein loss in prostate adenocarcinoma is associated with faster disease progression and reduced benefit from current standard-of-care therapies. Roughly 25% of patients with metastatic hormone-sensitive prostate cancer (mHSPC) are estimated to have PTEN-deficient tumors as assessed by IHC.
The assay approval reflects a growing shift toward molecular stratification in prostate cancer, where identifying actionable biomarkers can guide selection of targeted combination therapies earlier in the disease course.
Matt Sause, CEO of Roche Diagnostics, emphasized the clinical relevance of the decision, stating: “Prostate cancer is one of the leading cancer diagnoses for men in the United States,” and added that, “The FDA approval of our new companion diagnostic will provide clinicians with a vital tool to identify patients with PTEN loss and potentially provide new therapeutic options.”
How the assay works and clinical context
The VENTANA PTEN (SP218) RxDx Assay is a qualitative IHC test performed using the OptiView DAB IHC Detection Kit on a BenchMark ULTRA instrument. It is designed to assess PTEN protein expression in tumor tissue from patients with prostate adenocarcinoma.
PTEN-loss status is determined by pathologist evaluation of staining patterns, defined in the clinical development program as ≥90% of viable malignant cells showing no specific cytoplasmic PTEN staining. A positive result indicates absence or reduction of PTEN expression within tumor cells.
The FDA approval is supported by data from the CAPItello-281 clinical study, where the assay was used as the enrollment test to identify patients with PTEN loss. According to Roche, patients receiving TRUQAP-based combination therapy demonstrated a reduction in disease progression in this study setting.
Link to targeted therapy in metastatic disease
The assay is indicated as an aid in identifying patients who may be eligible for TRUQAP in combination with abiraterone acetate, in accordance with the therapy’s approved labeling. TRUQAP provides a new first-line treatment option for patients with PTEN-deficient metastatic androgen pathway modulation-naïve or sensitive prostate cancer (previously referred to as metastatic hormone-sensitive prostate cancer).
Metastatic hormone-sensitive prostate cancer is described as an aggressive disease state in which targeted combination therapies have historically been limited. The average survival following diagnosis of metastatic prostate cancer is approximately five to six years, underscoring the clinical need for improved stratification tools.
Foundation Medicine, an independent affiliate of Roche, is among the laboratories implementing the VENTANA PTEN (SP218) RxDx Assay to support clinical decision-making and patient identification for therapy selection.
Expanding precision oncology in prostate cancer
With this approval, Roche expands its companion diagnostic portfolio in oncology, reinforcing the integration of pathology-based biomarker testing into treatment decision pathways. The introduction of PTEN protein assessment via IHC adds a new layer of precision to prostate cancer management, particularly for identifying patients who may benefit from targeted combination therapy earlier in their disease course.
Note: This news summary was generated by AI based on a published press release, followed by a review from human editors.
