FDA approves Roche’s VENTANA PTEN (SP218) RxDx Assay, the first companion diagnostic to identify PTEN-deficient prostate cancer patients eligible for TRUQAP (capivasertib) treatment.
Written By: Kalyani Boharopi,
M.Pharm (Reg. Affairs)
Reviewed By: Pharmacally Editorial Team
Roche has received U.S. Food and Drug Administration (FDA) approval for the VENTANA PTEN (SP218) RxDx Assay, the first immunohistochemistry (IHC)-based companion diagnostic approved to identify PTEN protein loss in prostate adenocarcinoma.
The test helps determine eligibility for treatment with AstraZeneca’s TRUQAP (capivasertib) in combination with abiraterone acetate, which received FDA approval on June 12, 2026, for patients with PTEN-deficient metastatic androgen pathway modulation-naïve or sensitive (mAPMN/S) prostate cancer. Together, the approvals establish a new precision medicine approach for this molecularly defined patient population.
The approval provides clinicians with a validated tool to identify patients whose tumors exhibit PTEN deficiency, a biomarker associated with aggressive disease biology, faster progression, and poorer outcomes with current standard-of-care therapies.
The assay supports treatment selection for patients with metastatic androgen pathway modulation-naïve or sensitive (mAPMN/S) prostate cancer, a disease setting previously known as metastatic hormone-sensitive prostate cancer (mHSPC).
Addressing an Important Biomarker in Prostate Cancer
PTEN is a tumor suppressor protein that regulates cellular growth and survival pathways. Loss of PTEN function is among the most common molecular alterations observed in prostate cancer and has been linked to increased tumor aggressiveness and resistance to conventional therapies.
Approximately one-quarter of patients with metastatic hormone-sensitive prostate cancer have PTEN-deficient tumors when assessed by immunohistochemistry. These patients historically lacked therapies specifically targeting the biological consequences of PTEN loss.
TRUQAP, an AKT inhibitor, offers a targeted treatment approach for this molecularly defined subgroup. By identifying PTEN-deficient tumors, the VENTANA PTEN (SP218) RxDx Assay enables clinicians to incorporate biomarker-driven treatment decisions into routine clinical practice.
CAPItello-281 Supported Approval
FDA approval of the companion diagnostic was supported by the Phase 3 CAPItello-281 (NCT04493853), where the assay served as the enrollment tool for identifying patients with PTEN-deficient tumors.
The assay determines PTEN protein loss based on pathologist assessment of tumor tissue. PTEN deficiency is defined as the absence of specific cytoplasmic staining in at least 90% of viable malignant cells.
Results from CAPItello-281 showed that patients with PTEN-deficient metastatic prostate cancer who received TRUQAP in combination with abiraterone experienced a statistically significant and clinically meaningful reduction in disease progression compared with standard treatment approaches. These findings established PTEN loss as a clinically actionable biomarker and supported the regulatory approval of both the therapy and its companion diagnostic.
Roche Expands Its Companion Diagnostics Portfolio
According to Matt Sause, Chief Executive Officer of Roche Diagnostics, the approval provides clinicians with a critical tool to identify patients with PTEN loss who may benefit from additional treatment options.
The VENTANA PTEN (SP218) RxDx Assay runs on Roche’s BenchMark ULTRA platform using the OptiView DAB IHC Detection Kit. Foundation Medicine, an independent affiliate of the Roche Group, is among the laboratories offering testing with the approved companion diagnostic.
What the Approval Means for Patients
Metastatic hormone-sensitive prostate cancer remains an aggressive disease, with average survival after diagnosis generally ranging between five and six years. The introduction of a validated PTEN companion diagnostic strengthens efforts to personalize treatment by matching patients to therapies based on tumor biology rather than clinical characteristics alone.
The FDA approval further expands the role of biomarker-guided treatment in prostate cancer and reinforces the growing importance of companion diagnostics in bringing targeted therapies to the patients most likely to benefit.
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About the Writer
Kalyani Boharapi (LinkedIn) is a pharmacy professional and healthcare writer currently pursuing an M.Pharm in Regulatory Affairs at Dr. D. Y. Patil College of Pharmacy, with interests in pharmaceutical regulations, drug development, and healthcare innovation. She has academic exposure to dossier preparation, scientific writing, and regulatory documentation. Kalyani has also completed certification courses in Generative AI, AI in Pharma, and Bioinformatics, and actively participates in pharmaceutical conferences to stay updated with emerging trends and advancements in the healthcare and pharmaceutical industry.