Good pragmatic question though. It's not clear if any drugs up- or down-regulate Obelisk genome copy, you could re-investigate other drug-treatment studies to see if Obelisks incidentally present are altered and get an "accidental" study.

From a molecular perspective, the most likely compounds and methods would be those which work against viroid replication (i.e. RNA polymerase inhibitors, translational inhibitors, CRISPR,...). You just have to maintain a preferential toxicity to Obelisks over host cells.