Last Zacks small-cap research report for RVX dated 4/10/2019:

https://scr.zacks.com/News/Press-Releases/Press-Release-Details/2019/RVX-BETonMACE-Final-Event-Expected-April-2019-article/default.aspx

"Research articles, as seen here, are part of the service Zacks provides and Zacks receives quarterly payments totalling a maximum fee of $30,000 annually for these services." 

Perhaps RVX did not renew with Zacks for 2020 @ an annual fee of $30K.

Koo