Ann: Preclinical Studies Justify Mode of Delivery for Anisina, page-21

You're missing the point. You need to get this drug in the blood then through the blood brain barrier (BBB) to work in Neuroblastoma, this model shows that it will do that and also has clinical efficacy.
IV dosing generally avoids liver "first pass effect" problems and give higher blood levels with lower doses, less potential adverse effects. All good news in my opinion. Oral dosing may be useful in some cases and slow release and other formulations maybe useful strategies to improve bioavailability.