Here is a concise article that was published recently in the BioEntrepreneur blog that makes a convincing argument in our opinion for pursuing an in-licensing business model approach to starting a pharmaceutical company. Note the figures, the inflection points in the valuation curve and the required investment to reach each milestone or potential exit point for investors.

https://www.nature.com/bioent/2003/030101/full/nbt0602supp-BE36.html