How can the HBEL model be applied to early phase Investigational Medicinal Products (IMPs) where limited data is available?

Health based exposure limits should be established based on all available data and as such assessments associated with IMPs should be regularly reviewed for presence of new data. Toxicology experts should also make judgments about the future potential of the material to demonstrate critical effects where key toxicological testing has not been completed (e.g. this may be based on comparison to other similar molecules where available) and any additional adjustment factors that may be appropriate. This would allow manufacturers to assume worst case and make sound judgments on the level of organisational and technical control measures required.