Developing accelerated proof-of-concept (AcPOC) protocols can be very challenging, as they require all the clinical pharmacology and medical experience and expertise that go into designing, conducting and analyzing data from single ascending dose (SAD), multiple ascending dose (MAD), and proof-of-concept (POC) studies. However, AcPOC designs are made even more complicated by the fact that these studies are run concurrently. Early cohorts of the MAD study may be starting while late-stage cohorts of the SAD study are still being conducted. Therefore, the protocols need to have the flexibility to allow the designs to be adapted as each stage progresses. As with many early clinical development programs, protocol amendments may be needed, since the pharmacokinetic parameters used in the design are not based on human data but extrapolated from the preclinical data. This is why Cetero often makes our protocols more flexible. From the beginning, they are “adaptable” in their design and in the dosing regimens to be studied.