While Next-Generation Sequencing (NGS) is common, the FDA label for Capivasertib specifically requires Immunohistochemistry (IHC) to establish PTEN deficiency for treatment eligibility. This is because the critical factor is the functional loss of the PTEN protein, which IHC directly measures, making it non-negotiable for insurance approval.
The efficacy of the AKT inhibitor Capivasertib is not uniform across all PTEN-deficient tumors. An analysis revealed that patients with 100% loss of the PTEN protein experienced the most significant benefit, with a 12-month improvement in radiographic progression-free survival. This highlights a direct correlation between the degree of protein loss and treatment response.
The prevalence of PTEN loss is not static; it increases significantly as prostate cancer advances. While less common in localized disease, it can be found in up to 25% of patients with metastatic disease. This escalating frequency with disease progression underscores its role as a key driver of cancer advancement and a critical therapeutic target in later stages.
The approval of the AKT inhibitor Capivasertib has transformed PTEN testing from a prognostic tool for aggressive disease into a mandatory predictive test. Every patient with newly diagnosed metastatic prostate cancer should be assessed to determine eligibility for this targeted therapy, marking a significant shift in the standard of care.