"Is there an average drop-out rate in these sort of trials,..?" 

Discontinuation/Drop out rates in clinical trials depend on many variables including, but not limited to, the patient population, trial length, and drug(s) being tested. I don't know what the discontinuation/dropout rates were in the other apabetalone Phase 2 trials. Regardless, none of those exceeded 6 months of dosing and did not have the same patient population as BETonMACE. As we've referenced several times on this board, the EXAMINE and ELIXA trials have in common with BETonMACE high-risk diabetes patients with a recent ACS event. 

In EXAMINE, which had a median dosing period of about 18 months: "The rate of premature discontinuation of the study drug was similar in the alogliptin and placebo groups (20.9% and 22.6% of patients, respectively)."

In ELIXA, which had a median dosing period of about 23 months: "Excluding the 51 patients in the lixisenatide group and 41 in the placebo group who were taking the study medication on the day of death, the study medication was permanently discontinued in 833 patients (27.5%) in the lixisenatide group and in 727 (24.0%) in the placebo group (P=0.002)." 

"Could we expect more than 150 patients to have dropped out,..?"

With a total enrollment of 2425 patients in BETonMACE, 150 patients would only be a 6.2% discontinuation/drop out rate. So it is reasonable to expect more than 150 patients in BETonMACE to have dropped out. There is not guarantee that BETonMACE will have discontinuation/drop out ranges similar to EXAMINE and ELIXA, but if it does then the number will be much higher than 150.

"Also does it matter which group patient drop out,... I would imagine those taking RVX-208 not dropping out as much as the placebo group patients dropping out would be good for the trial results,...?"

Of course it matters. One wants a drug that is both safe and effective. We probably won't see the full safety and adverse event profile for apabetalone in BETonMACE until full data presentation and/or publication. The reason for the discontinuation/drop out is very important. Best case scenario, apabetalone and placebo discontinuation/drop out rates are similar. What we don't want to see is a significant increase in discontinuations/drop outs due to apabetalone, especially if it can be attributed to one or more specific adverse events related to the study drug.

BearDownAZ