Paper of the Month October

Discussion:

By selecting this paper, I would like to stress once again the importance of prospective studies in the development and in vivo evaluation of potential new tracers and their corresponding drug registration.  Especially in the field of PSMA tracers, there is still a lot of work to be done here.

As early as 2004, the FDA published guidelines for the design, analysis and interpretation of clinical trials for the development of medical imaging drugs and biological products.  Where phase I studies focus on the pharmacokinetic mapping and the human safety assessments, phase II studies mainly include the refining the mass dose and radiation dose ranges, providing preliminary evidence of efficacy, expanding the safety database and optimizing of the scanning protocol (image time, acquisition time) and eventually discussing the criteria by which the images will be evaluated.  The principle goal of phase III studies consists in the confirmation of efficacy of the radioligand especially in studies where a comparator radioligand or technique will be used.

In recent years, the nuclear community has been overwhelmed by the very good results of the PSMA radiotracers.  However, the design of most studies (both large populations and comparisons with other radiopharmaceuticals) are, with a few exceptions, mainly retrospective.  With the choice of this article, I would like to emphasize once again prospective studies with comparator drugs.

Another limitation of the retrospective studies is the lack of potential interesting information that can be linked to the PSMA scans such as patient outcome, PSA kinetics and the influence of the PSMA scan on patient policy.

https://www.ncbi.nlm.nih.gov/pubmed/31375469

https://www.thelancet.com/journals/lanonc/article/PIIS1470-2045(19)30415-2/fulltext