I'm not a scientist, but perhaps the answer to your question is implied somewhere in this section and given RVX-208 is a BRD2 inhibitor it blocks an important interaction point for the virus, here's the section:

Also note that in the lower part of the study in Table 1a. Literature-deriveda drugs and reagents that modulate SARS-Cov-2 interactors...RVX-208 is listed "in the pole position" with JQ1 at the top of the list.  Not sure how important this is actually but it is just nice to see any kind of recognition/exposure. 

"SARS-CoV-2 envelope interacts with bromodomain proteins

Surprisingly, we find that the transmembrane protein E binds to the bromodomain-containing proteins BRD2 and BRD4 (Fig. 4d, Extended Data Fig. 9), potentially disrupting BRD-histone binding by mimicking histone structure.

BRD2 is a member of the bromodomain and extra-terminal (BET) domain family whose members bind acetylated histones to regulate gene transcription69. The N-terminus of histone 2A shares local sequence similarity over analpha-helix of approximately 15 residues, some of which are in a transmembrane segment, of Protein E (Fig.4d).

Moreover, this matching region of the histone is spanned by acetylated lysine residues shown to bind BRD2 (70). This analysis may suggest that Protein E mimics the histone to disrupt its interaction with BRD2, thus inducing changes in host's protein expression that are beneficial to the virus.

For a more comprehensive overview of the virus-host interactions we detected, see Supplemental Discussion."

Hope this helps.