Nonclinical & clinical interface - extrapolation of nonclinical data to support Phase I clinical studies

A review of the Investigator's Brochure and Clinical Study Reports for 58 non-oncology small molecule and biopharmaceutical drug candidates tested in a healthy volunteer subject population was conducted. Key findings were (1) a vital role for nonclinical pharmacology and toxicology testing was confirmed to allow setting of clinical starting dose and supporting use of highest dose based on No Observed Adverse Effect Levels (NOAELs), Pharmacologically Active Doses (PADs) and other approaches, (2) for clinical starting dose calculation, reference to the NOAEL was key, whether in calculation of a Maximum Recommended Starting Dose (MRSD), or by supporting PAD approaches (small molecules); or, through pharmacokinetic/pharmacodynamic (PK/PD) data modelling (biopharmaceuticals), (3) starting dose for small molecules was very conservative with human exposure >100- to 100-fold (46%) lower or between 10- and 100-fold (41%) lower than that seen at the NOAEL; high margins over exposure seen at NOAELs were also seen for biopharmaceuticals, (4) at the highest doses used, about 25% of studies for small molecules and 12% of studies for biopharmaceuticals showed exposure greater than that seen at the NOAEL and (5) adverse event evaluation showed that our current paradigm of moving from nonclinical testing into SAD/MAD Phase I testing is remarkably safe.