Recognizing that radioligand therapy is most effective early when tumors are "target-rich," new clinical trials accelerate dosing and intensity upfront. This strategy aims to deliver the most significant therapeutic blow before diminishing returns set in as the tumor responds and the target is lost.

The effectiveness of radioligand therapy is counterintuitive: as tumors shrink and PSMA binding sites decrease, less radiation is delivered to the cancer. The VISION trial showed the first two doses delivered more radiation to the tumor than the subsequent four, questioning the value of a fixed, prolonged treatment schedule.

In advanced prostate cancer with few options, clinicians retreat patients with radioligand therapy after an initial response, despite a lack of formal data. The rationale is practical: for a patient who previously responded well and has no better alternatives, reusing an effective therapy is a logical clinical decision.

Lutetium faces criticism for its fixed 6-cycle regimen, which may be suboptimal as the PSMA target diminishes with ADT. However, this critique is rarely applied to other drugs like PARP inhibitors, which are given until progression. This highlights a double standard and the tension between using a fixed regimen for regulatory approval versus finding the optimal dose in practice.

While Pluvicto (lutetium) is approved for six cycles, clinicians are retreating relapsed patients who previously responded well. This common practice occurs in a "data-free zone," driven by the lack of better options and the logic that a previously effective drug may work again in a patient selected for prior response.

Medical oncologists are trained to treat continuously to eliminate micrometastatic disease. Radioligand therapy challenges this dogma, as its effectiveness is tied to target volume. As tumors shrink, the therapy becomes less potent against the cancer and relatively more toxic to healthy organs, requiring a mental shift to an adaptive, physics-based model.

Unlike chemotherapy, radioligand therapy's effectiveness wanes as tumors shrink. With less PSMA target for the drug to bind to, less radiation is delivered to the cancer. This physical reality supports "adaptive dosing"—stopping treatment in high-responders to spare healthy tissue and resume later if needed.

A contrarian viewpoint, dubbed the "Gillison Paradox," argues that patients achieving a complete response are precisely the ones who should receive more therapy. Their strong response indicates drug sensitivity, making it logical to continue treatment to eradicate any remaining micrometastatic disease, rather than de-escalating.

The PSMA edition trial's fixed six-cycle Lutetium regimen, designed nearly a decade ago, is now seen as suboptimal. This illustrates how the long duration of clinical trials means their design may not reflect the latest scientific understanding (e.g., adaptive dosing) by the time results are published and debated.