Diagnostic to Identify PTEN Deficiency Launched For Patients With Prostate Cancer

PTEN IHC CDx, the first immunohistochemistry (IHC) companion diagnostic test approved by the FDA for patients with prostate adenocarcinoma, is now available, according to a news release from NeoGenomics.¹

The IHC test is a companion diagnostic used to identify patients eligible for capivasertib (Truqap), which was recently approved for PTEN-deficient metastatic prostate cancer.

The test detects PTEN protein loss using the VENTANA PTEN (SP218) RxDx Assay and is available as a standalone order or as part of NEO PanTracer™ Pro, a molecular workup option that combines comprehensive genomic profiling and cancer-type–directed IHC testing.

Approval of Capivasertib in PTEN-Deficient Population

The FDA approved capivasertib in combination with abiraterone acetate (Zytiga) and prednisone on June 12, 2026, based on results from the phase 3 CAPItello-281 trial (NCT04493853).² In that trial, 1012 patients with newly diagnosed, PTEN-deficient metastatic androgen pathway modulation-naive or -sensitive (mAPMN/S) prostate cancer were randomly assigned 1:1 to capivasertib plus abiraterone or placebo plus abiraterone, each with prednisone and background androgen deprivation therapy.³

In the trial, 1519 of 6003 (25.3%) patients with valid tumor test results had PTEN-deficient tumors. The diagnostic cutoff was at least 90% viable malignant cells with no specific cytoplasmic PTEN IHC staining.

The trial met its primary end point of radiographic progression-free survival (rPFS), with a median of 33.2 months (95% CI, 25.8-44.2) in the capivasertib arm vs 25.7 months (95% CI, 22.0-29.9) with placebo (HR, 0.81; 95% CI, 0.66-0.98; P =.034). The rPFS benefit was consistent across prespecified subgroups regardless of baseline disease risk or extent of metastatic involvement.

Additionally, post hoc rPFS analyses for PTEN cutoffs 95% or higher, 99% or higher, and 100% showed consistent outcomes for the capivasertib arm, whereas worse outcomes were observed as the degree of PTEN deficiency increased in patients who received abiraterone without capivasertib.

Approval followed a 7-to-1 vote by the FDA’s Oncologic Drugs Advisory Committee. The FDA concurrently cleared the VENTANA PTEN (SP218) RxDx assay as the companion diagnostic at the time of approval.²

Patient Population and Diagnostic Rationale

Of the approximately 35,000 patients diagnosed each year with mAPMN/S prostate cancer, roughly 1 in 4 have PTEN-deficient tumors.¹ PTEN protein loss is detectable through a tissue-based test at the time of diagnosis, making access to a fast, accessible companion diagnostic of particular importance for timely treatment decisions in the community setting, where the majority of patients with advanced prostate cancer are managed.

“Clinicians treating this aggressive form of prostate cancer have long needed both a targeted therapy and a validated way to identify eligible patients,” Nathan Montgomery, MD, PhD, vice president of medical services at NeoGenomics, stated in a news release. “With PTEN IHC CDx now integrated into NEO PanTracer Pro, community oncology practices have an FDA-approved companion diagnostic available through a single national laboratory partner.”

REFERENCES

1. NeoGenomics launches FDA-approved PTEN IHC companion diagnostic for prostate cancer. News release. NeoGenomics. July 9, 2026. Accessed July 9, 2026. https://tinyurl.com/bdcn5tw4

2. TRUQAP (capivasertib) combination approved in the US as first and only targeted treatment for PTEN-deficient metastatic hormone-sensitive prostate cancer. News release. AstraZeneca. June 12, 2026. Accessed July 9, 2026. https://tinyurl.com/yc2ac87m

3. Fizazi K, Clarke NW, Santis MD, et al. Capivasertib plus abiraterone in PTEN-deficient metastatic hormone-sensitive prostate cancer: CAPItello-281 phase III study. Ann Oncol. 2026;37(1):53-68. doi:10.1016/j.annonc.2025.10.004