CONVERT‑HB1: a Phase 2 Trial About Prostate Directed Treatment After Systemic Treatment in mHSPC

CONVERT‑HB1 trial addresses a long‑standing uncertainty in metastatic hormone‑sensitive prostate cancer: whether aggressively treating the primary prostate tumor adds meaningful benefit for patients who already have high‑volume metastatic disease and are receiving modern intensified systemic therapy. For years, data from studies like STAMPEDE and HORRAD suggested that local treatment to the prostate might help men with low‑volume or oligometastatic disease, but the signal in high‑volume populations was weak, inconsistent, or absent.
At the same time, systemic therapy has evolved from simple androgen deprivation to powerful doublets and triplets that can produce deep biochemical and radiographic responses, especially when combined with next‑generation AR pathway inhibitors and, in some cases, PARP inhibitors. The key open question has been whether, in the era of such intensified systemic control, consolidative treatment of the primary still matters for patients who start out with a heavy metastatic burden, or whether the biology of high‑volume disease makes local treatment largely irrelevant once distant disease has declared itself.

The importance of this trial lies in three main conceptual advances. First, it specifically focuses on high‑volume metastatic patients, the group historically considered least likely to derive added benefit from local control of the prostate, and asks the question again under contemporary treatment conditions rather than older ADT‑only paradigms. By doing so, it directly challenges a quietly entrenched assumption in many treatment algorithms: that local therapy is for oligometastatic or low‑volume disease, and that high‑volume patients should be managed systemically only.
Second, it uses PSMA PET/CT not just as a staging tool but as a biomarker of “conversion success”, selecting for patients whose metastatic lesions become metabolically silent on imaging after induction systemic therapy. This is a major conceptual shift. Instead of basing decisions only on baseline volume or conventional imaging, it leverages a functional, PSMA‑based definition of deep response to identify a subgroup of high‑volume patients whose biology may be more favorable than their initial burden suggested. The trial is therefore testing whether, once systemic therapy has effectively “switched off” visible disease, consolidating the primary becomes relevant again, even in those who began with extensive spread.
Third, the study is embedded in the reality of modern practice: it allows intensified systemic therapy with ADT plus second‑generation AR pathway inhibitors, often combined with docetaxel and, where appropriate, other agents such as PARP inhibitors. That makes its findings intrinsically more applicable to current standards of care than older trials that only used ADT.

If the results show that adding local prostate treatment improves progression‑free or overall survival on top of powerful systemic regimens in this carefully selected high‑volume cohort, it would support a more aggressive, multimodal approach and potentially reshape guidelines for a group historically written off as “too metastatic” for local therapy.
Conversely, if no significant benefit is observed despite deep PSMA‑documented responses and modern systemic backbones, that would give strong evidence that, at least for truly high‑volume disease, the focus should remain squarely on systemic control and that local treatment can reasonably be omitted even when the prostate lesion remains.

Clinical trial.