Results
In vivo studies for cell-based therapies were primarily aimed at proof-of-concept (75/86), followed by addressing safety (64/86), biodistribution (49/86) or tumourigenicity (46/86). No animal studies were performed or proposed by sponsors or regulators for six (out of 86) products, which contained cell types that have been studied in humans for a relatively long time. For one-third of the products in vivobiodistribution and/or tumourigenicity studies were not considered necessary. In vivo tumourigenicity studies were regarded of limited value.