'The blood–brain barrier is generally very effective at preventing unwanted substances from accessing the brain, which has a downside. The vast majority of potential drug treatments do not readily cross the barrier, posing a huge impediment to treating mental and neurological disorders.
One possible way around the problem is to “trick” the blood–brain barrier into allowing passage of the drug. This is the so-called Trojan horse approach, in which the drug is fused to a molecule that can pass the blood–brain barrier via a transporter protein.
A different approach is to temporarily open the blood–brain barrier using ultrasound.'
Jürgen Götz, Director, Clem Jones Centre for Ageing Dementia Research, The University of Queensland explains how the blood brain barrier works and ways it can be breached: theconversation.com/explain...
While CLL infiltration of the Central Nervous System(CNS)/brain is rare, it can happen. As the article mentioned, small molecules can pass through the blood-brain barrier and Ibrutinib appears to have a promising role in treating CLL infiltration of the CNS: bloodjournal.org/content/12...
There have been a few attempts at trials with Rituximab, but slow recruitment challenges the ability to gain adequate data.
Photo: Eucalyptus (gum tree) blossom