Radioligand Therapy Plus CAR‑T: A New Strategy to Reprogram the Prostate Cancer Microenvironment

A new preclinical study shows that radioligand therapy (RLT) can directly enhance CAR‑T cell efficacy in metastatic castration-resistant prostate cancer (mCRPC), addressing two major barriers: antigen heterogeneity and an immunosuppressive tumor microenvironment (TME).

Researchers combined 177Lu‑PSMA‑617(Pluvicto) with PSCA-targeted CAR‑T cells in sequence (RLT → cyclophosphamide → CAR‑T). Compared to either treatment alone, the combination significantly improved tumor control and survival across models, including those with heterogeneous antigen expression.

The key finding is mechanistic. RLT is not acting only as a cytotoxic agent, it functions as an immune primer. Treatment induces immunogenic tumor cell death, increases antigen release, and shifts the TME toward a pro-inflammatory state. This includes activation of endogenous T cells and remodeling of the myeloid compartment.

As a result, CAR‑T cells show improved activation, effector function, and likely tumor infiltration. In practical terms, RLT converts a “cold” prostate tumor into a more permissive environment for cell therapy.

The study also tested 225Ac‑PSMA‑617, observing similar combinatorial activity, suggesting this immune-priming effect may extend across different radioligand platforms.

These findings align with ongoing clinical efforts combining RLT with immunotherapy, particularly checkpoint inhibitors. The addition of CAR‑T represents a more aggressive strategy, potentially overcoming both immune exclusion and antigen escape through a dual-target approach (PSMA + PSCA).

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