Biotech Values

[Summer2762]

Since the PR you referenced had the following quote mentioning 0.046, I assumed the interim's pre-defined statistical threshold for efficacy was around p<~0.005 and with 350 patients at interim, I was not expecting the study to show a large treatment difference at the final and thus did not consider risk/reward favorable for investment.

As a result of these recommendations, top-line efficacy data from the PEARL-SC clinical study is expected in the second quarter of 2012. With 547 patients the study retains greater than 90% statistical power to detect a treatment difference of 14% with an associated p-value of less than 0.046 (p < 0.046) for the study's primary endpoint*.

However, it came to my attention that this study was supposed to enroll ~600 patients as opposed to 547 patients mentioned above. ( http://clinicaltrials.gov/ct2/show/NCT01162681 ). Could some of the drop at final from 0.05 to 0.046 be related to this change and not to alpha lost at the interim? Does anyone know if the the co played with the power or the effect size after the study was started?


Thanks