Manufacturing of PSMA-T4 radiopharmaceutical kit for 99mTc labelling as an investigational medicinal product - considerations regarding compliance with GMP.

Prostate-specific membrane antigen (PSMA) is overexpressed in both primary and metastatic prostate cancer, making it a promising target for molecular imaging and therapy. The newly developed [99mTc]Tc-PSMA-T4 is an attractive alternative to 68Ga-labelled radioligands due to its lower cost and wider availability of SPECT/CT technology. The beneficial biological and chemical properties of [99mTc]Tc-PSMA-T4, such as its high stability, high affinity for PSMA, and favorable biodistribution with lower kidney accumulation, led to human phase I studies to further evaluate its safety and usefulness for diagnosing prostate cancer. The first-in-human use of the radiotracer demonstrated high diagnostic accuracy in detecting local recurrences and distant metastases, helping to select appropriate therapeutic strategies. The single-vial GMP-compliant lyophilization kit enables rapid on-site preparation with high radiochemical purity and stability. Validation studies confirmed consistent composition, low bioburden, and full compliance with the European Pharmacopoeia (Ph. Eur) specifications. Ongoing phase II/III clinical trials (NCT05847166) aim to further evaluate the diagnostic performance and safety of [⁹⁹ᵐTc]Tc-PSMA-T4, supporting its potential transition from an investigational medicinal product to a fully approved radiopharmaceutical for prostate cancer imaging.