https://www.cytel.com/blog/late-stage-clinical-development-strategy-trade-offs-and-decision-making-in-the-confirmatory-setting?utm_campaign=Cytel%20Blog%20Subscriptions&utm_medium=email&_hsmi=290919421&_hsenc=p2ANqtz--fsh89Kb18C9VTI0uTbJpbi2_8BBNT_7zceEZH8mJzvffHjMRO9XE7BH5ROaK6d1Q5Gvca7TQ673Ddpfy9kCfIMcu00g&utm_content=290919421&utm_source=hs_email

In this Cytel blog post, it says,

However, in some trials such as acute cardiovascular or immune-oncology trials, crossing or late separation of curves can be expected, which means that the assumption of proportional hazards is violated. Therefore, using the “conventional” methods may lead to loss of power and suboptimal interim decisions.

The BOM primary end point (p = 0.11) was time to event:

Incidence of first occurrence of MACE narrowly defined as a single composite endpoint of Cardiovascular (CV) Death (including undetermined cause of death) or Non-fatal Myocardial Infarction (MI) or Stroke. If a subject has multiple events, only the first event contributing to the composite endpoint is counted.

The analysis for this primary end point was done with Cox proportional hazard method. As the blog post says, it may lead to "loss of power" if this method was erroneously used when the proportional hazard (PH) assumption was violated, which is often the case in time to CV event outcome.

So, BOM, i.e, failed trial, could be due to applying wrong statistical analysis not "underpowering" issue. The population size could be sufficient, it's just that the PH assumption doesn't hold here, therefore, making the results invalid.

I'm not a stastician so please take my opinion with caution. RVX company should look into this matter.