Table 3.

Strategies that use alternative methods to improve drug delivery: clinical impact based on expectations from drug therapy^a

Strategy	Effectiveness for CNS Malignancy	Toxicity/Adverse Effects Profile	Introduction into Clinical Practice	Repeated/Continuous Administration	Tumor Size and CNS Location
Efflux transport inhibition without/with nanocarriers	No studies	High toxicity for first generation compounds. No data for new generation compounds.	No data. Potentially simple.	No data. Potentially possible.	No data. No limitation expected.
Systemic administration of drug nanocarriers without/with targeting molecules	Not established (few phase II studies).	Varies by carrier and compound. Require further investigation.	Potentially simple.	Potentially possible.	No data. No limitation expected.
Systemic administration of CNS-targeted drug carrier exosomes	No studies.	Safe by preliminary in vivo animal studies.	Potentially simple.	Potentially possible.	No data. No limitation expected.

^aFor references, please see text.