Biotech Values

[DewDiligence]

Example of how large ACS trials must be to be well-powered (from MDCO’s 3Q10 CC):

http://seekingalpha.com/article/232727-medicines-ceo-discusses-q3-2010-results-earnings-call-transcript

Clive Meanwell (CEO):

…[we are] redeveloping Cangrelor…an injectable P2Y12 platelet inhibitor for patients undergoing PCI, those awaiting major surgery while on clopidogrel [Plavix], and for those with acute coronary syndromes.

We are pleased to announce today that we have started the phase-3 trial, CHAMPION PHOENIX… The trial is a double-blind parallel-group randomized study comparing Cangrelor to clopidogrel. We assume a [control-arm] ischemic event rate at 48 hours of 5.1% and a 24.5% relative reduction in ischemic events [in the Cangrelor arm]. These assumptions are lifted directly from prior studies.

For 90% power, the required sample is estimated at 10,900 patients. The protocol foresees a possible sample-size re-estimation after interim analysis, in which case the trial may recruit up to 15,000 patients.

The reason these kinds of trials must be so large to achieve a statsig outcome is that relatively few patients in the trials experience an ischemic event during the observation period. Another way of saying this is that modern drugs used in the cath lab are remarkably effective.

Link to the clinicaltrials.gov entry for CHAMPION PHOENIX:
http://clinicaltrials.gov/ct2/show/NCT01156571