Researchers will test a new treatment for prostate cancer. This treatment uses an antibody tagged with a small amount of radioactive material. Researchers believe the new antibody might work better than those used before.
In the first part of the study researchers will compare the new treatment to the old one on prostate cancer patients using very low doses, not strong enough to treat nor to cause strong adverse reactions. Each patient will eventually receive both treatments, but one at a time.
The aim of the second part of the study is to find the best dose of the new treatment for patients. This means finding the dose that offers the most benefits with the fewest side effects.
The performance of different prostate cancer diagnostic methods is also in scope of the study.
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Male patients with age > 18 years
Clinical indication for RLT with 177Lu-PSMA-I&T (progressive PSMA-positive mCRPC patients after androgen receptor signalling pathway inhibitor and taxan-based chemotherapy or patient unfit for chemotherapy)
Patients will be included in Phase Ia while being under active therapy with 177Lu-PSMA-I&T (SoC) and after they have completed the first two cycles of 177Lu-PSMA-I&T RLT
Prior PSMA-targeted RLT (except for the 2 first cycles in Part Ia)
PSMA-negative (or PSMA-negative / FDG-positive) disease
Known intolerance against DOTA, DOTAGA, urea-based analogues or against any of the components/formulation of 177Lu-PSMA-I&T or 161Tb-SibuDAB solutions.
Ongoing infection at the screening visit or a serious infection in the past 4 weeks