Roche VENTANA PTEN (SP218) FDA-cleared as PTEN companion diagnostic in prostate cancer

Regulatory milestone

The VENTANA PTEN (SP218) RxDx Assay received U.S. FDA approval as the first immunohistochemical companion diagnostic to determine PTEN protein loss in prostate adenocarcinoma. The approval enables use of the assay to identify patients who may be eligible for treatment with capivasertib (TRUQAP) in combination with abiraterone acetate.

Clinical context and intended use

PTEN is a tumour suppressor protein; its loss is associated with faster disease progression and reduced benefit from standard treatments. The approved indication covers patients with PTEN‑deficient metastatic androgen pathway modulation‑naïve or sensitive (mAPMN/S) prostate cancer, a population previously described as metastatic hormone‑sensitive prostate cancer.

Evidence base

The approval is supported by the CAPItello‑281 phase III study, which used the assay as the enrollment test. Patients selected by the assay who received TRUQAP plus abiraterone experienced a statistically significant and clinically meaningful reduction in disease progression. The clinical cutoff for PTEN protein loss is ≥90% of viable malignant cells showing no specific cytoplasmic staining.

Deployment

Foundation Medicine is cited as an independent affiliate laboratory using the VENTANA PTEN (SP218) RxDx Assay. The test uses the OptiView DAB IHC Detection Kit on a BenchMark ULTRA instrument for staining.