How long from idea inception to initiation of the clinical trial

How long from idea inception to initiation of the clinical trial  

as of this writing we are not certain. However, HPI went public in April 1996, so we presume that the total time necessary for this discovery was considerably reduced from the average of 6.5 years that is typically quoted as the total time required from the original inception of the idea until entry into phase I trials. 

Did the candidate molecule arise from an optimization library of an existing lead or is it an analog of a lead structure discovered utilizing combinatorial methods  

This is the most intriguing aspect of the clinical candidate generated by the Houghten workers, since the discovery of HP228 was apparently the result of a lead generation library. This library provided the new chemical entity, which ultimately was the platform for further library optimization chemistry, which, in turn, provided the clinical candidate. This appears to be the only case to date of a lead generated by combinatorial methods, which, after optimization, has resulted in the clinical candidate. The other cases in the clinic that we have information about all arose from optimization libraries on existing leads. 

---