FDA Approves Roche PTEN Companion Diagnostic for Prostate

Roche has received approval from the U.S. Food and Drug Administration (FDA) for the VENTANA PTEN (SP218) RxDx Assay, becoming the first immunohistochemistry (IHC) companion diagnostic approved to identify PTEN protein loss in patients with prostate adenocarcinoma.

The approval enables clinicians to identify patients with PTEN-deficient prostate cancer who may be eligible for treatment with TRUQAP (capivasertib), AstraZeneca’s targeted therapy, in combination with abiraterone acetate.

According to Roche, the diagnostic assay is designed to assess PTEN protein expression in prostate tumour tissue and support treatment decisions for patients with metastatic androgen pathway modulation-naïve or sensitive prostate cancer, previously referred to as metastatic hormone-sensitive prostate cancer (mHSPC).

“Prostate cancer is one of the leading cancer diagnoses for men in the United States,” said Matt Sause, CEO of Roche Diagnostics. “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.”

PTEN is a tumour suppressor protein that plays a critical role in regulating cell growth. Loss of PTEN function is frequently observed across several cancer types and is associated with more aggressive disease. Roche estimates that approximately 25% of patients with metastatic hormone-sensitive prostate cancer have PTEN-deficient tumours.

The approval was supported by findings from the CAPItello-281 Phase III clinical trial, where the VENTANA PTEN (SP218) RxDx Assay was used to identify patients whose tumours exhibited PTEN deficiency. Results demonstrated that patients treated with TRUQAP-based combination therapy experienced a statistically significant and clinically meaningful reduction in disease progression.

The assay determines PTEN protein loss based on pathologist assessment, with PTEN deficiency defined as the absence of specific cytoplasmic staining in at least 90% of viable malignant cells.

Foundation of Precision Medicine, an independent affiliate of the Roche Group, is among the laboratories that will offer the companion diagnostic to help healthcare providers identify eligible patients.

The approval marks a significant advancement in precision oncology by enabling biomarker-driven treatment selection for patients with advanced prostate cancer, an area where targeted therapies addressing PTEN loss have previously been unavailable.