ira18,

1. What is known about duration of phase III clinical trials, ex. mean, and limits at 95% confidence level
This is like asking "how long are noses?" without specifying whether you mean humans or elephants. The duration of a clinical trial will vary depending on the length of time on study drug for one subject (ranging literally from minutes to years), length of follow-up (days to weeks), and challenges of recruitment and trial size (which mean a wide-ranging multiplication of the above numbers). All of which ignores whether you need one or several pivotal trials for the indication sought.

2. What is mean interval of time between completion of trial and presenting data to FDA?
6 months from last patient out to NDA submission is what many companies aim for.

3. When data presented to FDA, what is mean duration of time before the FDA either approves or disapproves drug for commerical use?

See the FDA's graphs at
http://www.fda.gov/cder/reports/reviewtimes/default.htm

4. What % of new drugs presented to the FDA win approval?
The success rate for a drug from NDA submission to marketing is high but has fallen recently. I hear numbers in the range of 80-90%. It is harder to calculate than you might think because of the indefinite category of "approvable" from which some drugs graduate to approval in weeks, others in years, and some not at all.

WCMinor