Stability matters: A study to evaluate In-vitro stability of Lu-177-PSMA-I&T

Introduction: In the Nuclear Medicine department, labelling radiopharmaceuticals and testing the quality of the labelled product before injecting it into patients is standard procedure in the department's in-house hot lab. Each labelled product has a varied shelf life, which determines how long a product can maintain in-vitro stability before it needs to be discarded. In the case of Lutetium-177 (Lu¹⁷⁷), it is proving to be revolutionary in the treatment of several advanced-stage tumours, such as metastatic castration-resistant prostate cancer (mCRPC) and Neuroendocrine Tumours (NET).

Methods: In our centre, all syntheses of Lu¹⁷⁷ with a peptide Prostate-specific membrane antigen Image and therapy (PSMA-I&T) were performed utilising an Eckert & Ziegler Eurotope's Modular-Lab Pharm Tracer® automated synthesis system for the treatment of metastatic castration-resistant prostate cancer. Additionally, sterile GMP-certified no-carrier-added Lu¹⁷⁷ from Australia's Nuclear Science and Technology Organisation was used in the experiment. Following each synthesis, the final product quality was evaluated by HPLC and Instant Thin Layer Chromatography-Silica Gel (ITLC-SG) at three different time points: 0 hours, 24 hours, and 48 hours. In addition, 35 batches of post-synthesis were completed between February-2020 to October-2020. As a result, the average radiochemical purity of ITLC-SG was greater than 99 per cent (99.70±.05 per cent), while the average radiochemical purity of HPLC was greater than 98 per cent (98.60±.05 per cent).

Results: As a result, the average radiochemical purity of ITLC-SG was greater than 99 per cent (99.70±.05 per cent), while the average radiochemical purity of HPLC was greater than 98 per cent (98.60±.05 per cent).

Conclusions: Current findings demonstrate that automated synthesis of Lu¹⁷⁷-PSMA-I&T with the help of Eckert & Ziegler Eurotope's Modular-Lab Pharm Tracer® can remain stable for an extended period of time, allowing it to be supplied from one location to another, which is suitable for logistical purposes and can be a help to save patients from having to travel from one location to another