Roche has announced a major regulatory milestone: the US FDA has approved its VENTANA PTEN (SP218) RxDx Assay—the first immunohistochemistry companion diagnostic test cleared to detect PTEN protein loss in prostate adenocarcinoma.
The FDA nod marks a step forward in precision oncology, linking molecular diagnostics more tightly to therapy selection for advanced prostate cancer.
The approval means patients with PTEN-deficient tumours may now be eligible for treatment with AstraZeneca’s targeted therapy TRUQAP (capivasertib), potentially expanding options for a population with historically limited precision-guided therapies.
“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 key tumour suppressor protein, and its loss is frequently seen across multiple cancer types. Roughly a quarter of patients with metastatic hormone-sensitive prostate cancer are estimated to have PTEN-deficient tumours, identified through immunohistochemistry testing.
The disease itself—metastatic hormone-sensitive prostate cancer—is an aggressive form of prostate cancer, with average survival after diagnosis estimated at about five to six years. Until now, no therapies have specifically targeted PTEN-loss biology in this setting.
The newly approved assay allows clinicians to identify patients who may benefit from combination treatment with TRUQAP and abiraterone acetate, aligning diagnostic precision with emerging targeted therapy strategies.
The approval is backed by results from the CAPItello-281 clinical study, where the assay was used to select patients whose tumours showed PTEN deficiency. In that study, patients receiving TRUQAP combination therapy experienced a statistically significant and clinically meaningful reduction in disease progression.
The test itself is a qualitative immunohistochemical assay performed on Roche’s BenchMark ULTRA platform using the OptiView DAB detection system. It determines PTEN status based on whether there is an absence or presence of PTEN expression in prostate adenocarcinoma tissue.
