VENTANA PTEN (SP218) RxDx Assay: FDA-approved prostate cancer companion diagnostic from Roche

Responsible: ad hoc news B2B & Pro Desk. Reviewed prior to publication on June 13, 2026 at 12:24:06 PM ET. Details in the imprint.

Roche is putting a fresh spotlight on precision diagnostics in prostate cancer with the newly FDA-approved VENTANA PTEN (SP218) RxDx Assay, a qualitative immunohistochemistry test designed to assess PTEN protein loss in prostate adenocarcinoma. According to Roche, this is the first immunohistochemistry companion diagnostic in the United States cleared specifically to determine PTEN deficiency and to help identify patients who may benefit from treatment with TRUQAP in combination with abiraterone acetate when used according to the approved therapeutic labeling. For oncology practices, pathology labs, and hospital systems, the assay expands the menu of clinically validated biomarkers that can guide therapy selection for a hard-to-treat cancer population.

What the VENTANA PTEN (SP218) RxDx Assay does in practice

The VENTANA PTEN (SP218) RxDx Assay is described by Roche as a qualitative immunohistochemical (IHC) assay that detects PTEN protein expression levels in formalin-fixed, paraffin-embedded (FFPE) tumor tissue from patients with prostate adenocarcinoma. PTEN is a tumor suppressor protein, and its loss or deficiency is associated with activation of the PI3K/AKT signaling pathway and with more aggressive disease biology in several cancer types, including prostate cancer, which makes PTEN status clinically relevant for treatment planning. By enabling pathologists to categorize tumors as PTEN protein-loss positive or negative via validated staining and scoring criteria, the assay provides a biomarker readout that can be used alongside other clinical and pathological factors when physicians evaluate systemic therapy options for eligible patients.

Roche notes that the newly approved test functions as a companion diagnostic linked to TRUQAP in combination with abiraterone acetate, meaning it is intended to be used to help identify patients whose tumors show PTEN protein loss and who may therefore be candidates for the specified targeted regimen, in accordance with the TRUQAP product label. In the companion diagnostic setting, assay performance characteristics such as sensitivity, specificity, and reproducibility are evaluated within a clinical trial framework; although Roche’s detailed performance tables are typically provided in the package insert and labeling, the company emphasizes in its communication that FDA approval confirms the assay has met regulatory requirements for analytical and clinical validation in the intended-use population. For laboratories, FDA approval also means the assay is available as an in vitro diagnostic kit rather than an LDT (laboratory developed test), which can simplify adoption in regulated environments.

From a workflow perspective, the VENTANA PTEN (SP218) RxDx Assay runs on Roche’s VENTANA BenchMark IHC/ISH instruments, which are widely installed in anatomic pathology labs globally. These automated staining platforms are designed to standardize IHC processes including deparaffinization, antigen retrieval, antibody incubation, detection, and counterstaining, reducing manual handling and inter-technologist variability compared with fully manual IHC protocols. By integrating PTEN testing into an already familiar VENTANA workflow, laboratories that are equipped with BenchMark systems can add the new companion diagnostic to their prostate cancer panels without major capital expenditures or extensive retraining, which may shorten the time from FDA approval to routine clinical use.

Roche has highlighted that the launch of the VENTANA PTEN (SP218) RxDx Assay addresses what it describes as an unmet medical need in prostate adenocarcinoma, where treatment decisions increasingly depend on molecular and protein biomarkers yet standardized, regulator-approved testing solutions have been limited for certain pathways. In recent years, clinicians have gained access to predictive biomarkers such as homologous recombination repair (HRR) gene alterations and MSI status in prostate cancer, but specific, FDA-cleared tools to assess PTEN protein loss using IHC have not been available until now, according to the company’s announcement. The new assay therefore extends the set of actionable tests that can be performed on existing FFPE biopsy or surgical specimens, potentially improving the personalization of care in advanced disease settings.

Roche positions the assay within its broader oncology diagnostics portfolio, which spans tissue-based biomarkers, circulating tumor DNA tests, and digital pathology solutions across different tumor types. Within this framework, PTEN joins other targeted markers in prostate cancer that Roche and its Genentech unit address on both the diagnostic and therapeutic sides, reinforcing a strategy in which companion diagnostics are developed in parallel with oncology drugs or combinations to support the safe and effective use of those medicines. For payers and hospital decision-makers, the combination of an FDA-approved diagnostic with a defined therapeutic indication can provide a clearer path to reimbursement and coverage than unvalidated or laboratory-specific assays, which is increasingly important as biomarker-guided therapies expand.

Roche underscores that the VENTANA PTEN (SP218) RxDx Assay is intended as an aid to clinical decision-making and is not a stand-alone determinant of treatment, meaning that physicians must interpret test results in the context of each patient’s overall clinical status, additional laboratory findings, imaging, and preferences. As with most companion diagnostics, pre-analytic factors such as tissue handling, fixation time, and storage conditions can affect IHC staining quality, and laboratories are expected to follow standardized procedures and participate in quality assurance programs when implementing the assay. Roche typically provides detailed instructions for use, control materials, and training resources via its diagnostics portal at diagnostics.roche.com, helping lab directors establish and maintain validated workflows, though site-specific validation still lies with the implementing institution.

For the US market, Roche’s announcement confirms that the VENTANA PTEN (SP218) RxDx Assay is cleared by the FDA for use in the United States as an in vitro diagnostic medical device, and that it is commercially available as part of the company’s VENTANA-branded tissue diagnostics lineup. As with other specialized oncology diagnostics, pricing is usually determined on an institution-by-institution basis and can vary based on contract agreements, volumes, and service arrangements; Roche has not publicly disclosed a single list price for the assay kit in US dollars in its initial communication, so buyers and procurement teams generally need to consult directly with Roche Diagnostics representatives for detailed commercial terms. In addition to hospital pathology labs, larger reference laboratories that process prostate cancer samples for community urologists and oncology clinics may also integrate the assay into their test menus, expanding access for patients beyond major academic centers.

Roche Holding AG reports that its diagnostics division, which includes immunodiagnostics, molecular diagnostics, and tissue diagnostics platforms like the VENTANA systems, generates multibillion-dollar annual revenues and is a core pillar of the group’s overall business next to its pharmaceuticals segment. Companion diagnostics such as the VENTANA PTEN (SP218) RxDx Assay are strategically important because they link test utilization directly to specific therapeutic use cases, potentially driving sustained demand for both the diagnostic and associated drugs over the life of a treatment paradigm. For laboratories and clinicians evaluating whether to adopt the assay, it is therefore reasonable to monitor how treatment guidelines, payer coverage decisions, and the real-world uptake of TRUQAP plus abiraterone evolve in relation to PTEN testing, since these factors will shape the assay’s long-term role in prostate cancer pathways. Shares of Roche Holding AG (CH0012032048, ticker RHHBY) last traded on the OTCQX market in the United States; recent US dollar pricing and historical data are available from financial data providers that track Roche’s participation shares.

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