For the purposes of this analysis, a small number of Phase 0, Phase I/II, Phase II/III, and Phase III/IV trials were combined with Phase I, Phase II, Phase III, and Phase IV trials, respectively. Overall, Phase II trials outnumbered all other trials by contributing between 52% and 62% across the period, or 57% on average.
The share of Phase I trials remained at around 31% across the 10-year period, as shown in Figure 1.
Phase III trials’ contribution ranged between 7% and 12%, or 9% on average, whereas Phase IV trials’ share remained flat at approximately 3%.
This shows the fast pace IO features with regard to the development of new drugs. It also highlights the relatively early stage the field is in, considering that 88% of the trials are in Phase II or below.