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FDA approvedFDA approved. Stage 4 of 4 (Authorized)

FDA Approves Roche's VENTANA PTEN Companion Diagnostic for Prostate Cancer

The tissue stain identifies tumors with PTEN protein loss, the group eligible for AstraZeneca's Truqap with abiraterone, under premarket approval P250031.

By News DeskJune 12, 20262 min read
Microscope image of prostate tissue with brown and red immunohistochemical staining
A micrograph of prostate tissue stained by immunohistochemistry with the PIN-4 antibody cocktail, a benign gland at left and adenocarcinoma at right. Not a PTEN (SP218) assay stain. Mikael Häggström, CC0, via Wikimedia Commons · CC0 1.0
FDA approvedPMA, high-risk device · P250031FDA approved. Stage 4 of 4 (Authorized)

The FDA approved this high-risk device through premarket approval (PMA), after reviewing clinical evidence of safety and effectiveness.

Key points

  • The FDA approved Roche's VENTANA PTEN (SP218) RxDx Assay under PMA P250031 on June 12, 2026.
  • The immunohistochemistry test aids in identifying prostate cancer patients who may be eligible for Truqap (capivasertib) with abiraterone acetate.
  • A tumor counts as PTEN-deficient when at least 90% of viable malignant cells show no specific cytoplasmic staining, the cutoff used in the CAPItello-281 study.

The US Food and Drug Administration has approved Roche's VENTANA PTEN (SP218) RxDx Assay, a tissue test that identifies prostate tumors lacking the PTEN protein, as a companion diagnostic for AstraZeneca's targeted drug Truqap (capivasertib), Roche said in a June 12 release. The company said it is the first immunohistochemistry companion diagnostic to receive FDA approval for determining PTEN protein loss in prostate adenocarcinoma.

The FDA's premarket approval database lists the assay under PMA P250031, filed by Ventana Medical Systems, Roche's Tucson, Arizona, tissue diagnostics unit. The application was received on August 18, 2025, and the decision is dated June 12, 2026. The record lists product code SHF, the pathology advisory committee, and clinical trial NCT04493853.

What the test does

According to the approval order statement, the assay is a qualitative immunohistochemical test using a rabbit monoclonal anti-PTEN antibody, clone SP218, on formalin-fixed, paraffin-embedded prostate adenocarcinoma tissue examined by light microscopy. It is run with Roche's OptiView DAB IHC Detection Kit on a BenchMark ULTRA staining instrument.

The FDA record says the test is indicated "as a companion diagnostic to aid in identifying patients who may be eligible for treatment with TRUQAP (capivasertib) in combination with abiraterone acetate." The clinical cutoff for PTEN loss is 90% or more of viable malignant cells with no specific cytoplasmic staining, and results should be interpreted by a qualified pathologist alongside histological examination, relevant clinical information and proper controls.

Trial basis and context

Roche said the approval is based on the CAPItello-281 study, in which the assay was used as the enrollment test to identify patients whose tumors showed PTEN loss. The company said patients who received the Truqap combination in that study experienced a reduction in disease progression. The release cites a Phase 3 CAPItello-281 paper published in Annals of Oncology in January 2026.

PTEN is a tumor-suppressor protein, and Roche said its loss in prostate cancer is associated with faster disease progression and reduced benefit from current standard treatments. About 25% of patients with metastatic hormone-sensitive prostate cancer have PTEN-deficient tumors as evaluated by immunohistochemistry, according to the release. Roche said Truqap gives a first-line option for patients with PTEN-deficient metastatic prostate cancer that is naive or sensitive to androgen pathway modulation, the group previously described as metastatic hormone-sensitive prostate cancer.

"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," said Matt Sause, chief executive of Roche Diagnostics, in the PDF version of the release. Roche said Foundation Medicine, an independent affiliate of the Roche Group, is one laboratory using the assay. The company did not say how many laboratories would offer the test at launch.

Sources

  1. Roche receives FDA approval for the first companion diagnostic to assess PTEN protein in people living with prostate cancer, Roche Diagnostics, June 12, 2026
  2. Roche receives FDA approval for the first companion diagnostic to assess PTEN protein in people living with prostate cancer (PDF media release), Roche Diagnostics, June 12, 2026
  3. PMA P250031: VENTANA PTEN (SP218) RxDx Assay (database record), US Food and Drug Administration, June 12, 2026