RE:RE:RE:Number needed to treat for RVX-208, the NNT ?"Any idea on an expected NTT?"
NNT is the inverse of the absolute risk reduction (ARR). ARR is the difference in actual event rates between the placebo and test group. The NNT should also state the duration and the adverse outcome being prevented. If we assume that apabetalone will elicit a 30% RRR and one guesstimates on the placebo event rate, we can get a ballpark ARR and NNT. For example, if placebo and apabetalone groups showed 12% and 8.4% event rates for 3-point MACE, respectively, at 18 months, this would be a 30% relative risk reduction (RRR) and a 3.6% ARR. 3.6% = 0.036. NNT = 1/ARR = 1/0.036 = 27.7. In other words ~28 patients would have to be treated for 18 months to prevent one 3-point MACE occurrence. If the 30% RRR is held constant, then the ARR will decrease and the NNT will increase as the actual placebo event rate drops. For example, if placebo and apabetalone groups showed 10% and 7% event rates for 3-point MACE, respectively, at 18 months, then the ARR is 3% and the NNT is 1/0.03 = 33.3.
BDAZ