Vol.:(0123456789) 1 3 Clinical and Translational Imaging https://doi.org/10.1007/s40336-018-0303-x SYSTEMATIC REVIEW Radiopharmacology and molecular imaging of PD‑L1 expression in cancer Sofia Carrilho Vaz 1  · Ana Sofia Capacho 1  · Francisco P. Oliveira 1  · Nuno Gil 1  · Carla Teixeira Barros 2  · António Parreira 1  · Durval C. Costa 1 Received: 10 September 2018 / Accepted: 8 October 2018 © Italian Association of Nuclear Medicine and Molecular Imaging 2018 Abstract Introduction Immunotherapy [(specifically, antibodies blocking programmed death ligand-1 (PD-L1)] is a valuable option in cancer treatment because it leads to durable tumour regression and improves survival in several cancers. Patients with PD-L1 expressing tumours benefit from this therapy, but currently it can only be determined through biopsy, which may be inconclusive or impossible due to lesion location, associated risks, intratumoral and interlesional heterogeneity. Therefore, radio-immune-imaging with a specific radiopharmaceutical is ideally placed to play an important role when performing real-time, in vivo, whole-body and non-invasive PD-L1 expression mapping. Purpose To describe and summarise published scientific data on imaging PD-L1 expression using radiopharmaceuticals and discuss future directions in this research field. Methods A summary review of the literature was done through PubMed to search papers that described and included radi- opharmaceuticals to image PD-L1 expression. Only English papers published until April 2018 that detailed laboratorial and animal procedures were selected. Results Eleven pre-clinical papers published between 2015 and 2018 were included. Four studies used anti-PD-L1 radiophar- maceuticals labelled with Indium-111, 4 with Copper-64, 2 with Fluoride-18 and 1 with both Copper-64 and Gallium-68. All of them had identical protocols and showed similar radiopharmaceutical biodistribution. They reported successful anti-PD- L1 labelling, with high tumour–background ratio (mainly when spleen uptake was saturated with unlabelled/cold antibody). Conclusions All reported radiopharmaceuticals had high sensitivity and specificity to identify tumours with PD-L1 expres- sion in animal model. Clinical experiments appear to be now justifiable. Keywords Anti-PD-L1 · Checkpoint inhibitors · Immunotherapy · Radiopharmacology · Molecular imaging · Nuclear medicine * Sofia Carrilho Vaz sofiacarrilhovaz@gmail.com Ana Sofia Capacho ana.capacho@fundacaochampalimaud.pt Francisco P. Oliveira francisco.oliveira@fundacaochampalimaud.pt Nuno Gil nuno.gil@fundacaochampalimaud.pt Carla Teixeira Barros carla.barros@fundacaochampalimaud.pt António Parreira antonio.parreira@fundacaochampalimaud.pt Durval C. Costa durval.costa@fundacaochampalimaud.pt 1 Champalimaud Foundation, Centre for the Unkown, Av. Brasília, 1400-038 Lisbon, Portugal 2 Faculdade deFarmácia da Universidade de Lisboa, Av. Prof. Gama Pinto, 1649-003 Lisboa, Portugal