Biotech Values

[DewDiligence]

Handicapping Satraplatin accelerated approval:

>With all Dew respect - what's your estimated odds for approval?<

I assume you are asking about accelerated approval, specifically, based on only the PFS data. I see the following cases (all figures are JMHO, FWIW):


1) FDA asks ODAC (or ODAC asks itself): “Should FDA wait a few months in order to see the overall-survival data?” I.e. the survival data are a focal point of ODAC’s evaluation.

• 1a) ODAC says: “Yes, let’s wait for the OS data.” Probability of accelerated approval is 16%.

• 1b) ODAC says: “No, don’t wait for the OS data—you have enough to approve without it.” Probability of accelerated approval is 88%.


2) The question in #1 above is not asked; i.e. the OS data are not a focal point of ODAC’s evaluation.

• 2a) ODAC finds the PFS data compelling. Probability of accelerated approval is 72%.

• 2b) ODAC finds the PFS data not compelling. Probability of accelerated approval is 4%.

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How to handicap the cases themselves? I would say that cases 1a, 1b, 2a, and 2b have probabilities of 48%, 26%, 19%, and 7%, respectively. Then the probability of accelerated approval is:

.48(.16)+.26(.88)+.19(.72)+.07(.04) = 45%.

If we know that OS is in fact a focal point of the ODAC analysis (case 1), then the probability of accelerated approval is:

(.48/(.48+.26))(.16)+(.26/(.48+.26)(.88) = 41%.

If we know that OS is not a focal point of the ODAC analysis (case 2), then the probability of accelerated approval is:

(.19/(.19+.07))(.72)+(.07/(.19+.07)(.04) = 54%.

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Obviously, the probability of accelerated approval would be very much better if the OS data were not almost mature. Once again, all numbers are JMHO, FWIW