Table 5. [FOLR1-Related Cerebral Folate Transport Deficiency: Targeted Therapy]. - GeneReviews®

5-formylTHF Therapy	Comment
Oral	Starting dose 2.5-5 mg/kg/day w/close monitoring of CSF folate levels, increasing dose as necessary	Oral administration is usually sufficient to bring CSF folate levels into the normal range for age. Monitoring CSF folate is essential to ensure that the dose of 5-formylTHF is sufficient, particularly when the clinical response is inadequate or there is a change in clinical status.
Intramuscular	Up to 40-50 mg/day ¹	This mode of administration & dose should be sufficient for therapeutic eval in persons w/FOLR1-CFTD who have an inadequate response to oral administration. (Note: There is substantial experience in intramuscular dosing in hereditary folate malabsorption.)
Intravenous	Variable ²	5-formylTHF has been administered intravenously periodically in some persons when the clinical response to oral 5-formylTHF was poor despite achieving CSF levels in the normal range. There have been anecdotal reports that this may result in some clinical improvement. ² There is no evidence that intravenous administration of 5-formylTHF is superior to intramuscular administration in FOLR1-CFTD.

5-formylTHF Therapy

Comment

Administration

Dose

Oral

Starting dose 2.5-5 mg/kg/day w/close monitoring of CSF folate levels, increasing dose as necessary

Oral administration is usually sufficient to bring CSF folate levels into the normal range for age. Monitoring CSF folate is essential to ensure that the dose of 5-formylTHF is sufficient, particularly when the clinical response is inadequate or there is a change in clinical status.

Intramuscular

Up to 40-50 mg/day ¹

This mode of administration & dose should be sufficient for therapeutic eval in persons w/FOLR1-CFTD who have an inadequate response to oral administration. (Note: There is substantial experience in intramuscular dosing in hereditary folate malabsorption.)

Intravenous

Variable ²

5-formylTHF has been administered intravenously periodically in some persons when the clinical response to oral 5-formylTHF was poor despite achieving CSF levels in the normal range. There have been anecdotal reports that this may result in some clinical improvement. ² There is no evidence that intravenous administration of 5-formylTHF is superior to intramuscular administration in FOLR1-CFTD.

From: FOLR1-Related Cerebral Folate Transport Deficiency

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Adam MP, Feldman J, Mirzaa GM, et al., editors.

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