diroximel fumarate: clinical use

Prescribing considerations

• Initiation should be supervised by a physician experienced in MS treatment.
• Obtain a recent baseline MRI and counsel the patient and carers about PML symptoms.
• Assess unresolved serious infection before initiation; consider interruption if a serious infection develops.
• Use caution with pre-existing lymphopenia, moderate or severe renal impairment, severe hepatic impairment or severe active gastrointestinal disease.
• Consider the previous therapy's half-life and immune effects when switching disease-modifying treatment.

Contraindications and cautions

• Hypersensitivity to diroximel fumarate, any excipient or another fumaric acid ester
• Suspected or confirmed progressive multifocal leukoencephalopathy
• Severe lymphopenia is a barrier to treatment initiation under the product precautions

Monitoring

• Check complete blood count, including lymphocytes, before and during treatment.
• Assess renal function before and during treatment and when clinically indicated.
• Check aminotransferases and total bilirubin before treatment and when clinically indicated.
• Reassess benefit and risk for sustained moderate lymphopenia and discontinue for prolonged severe lymphopenia in accordance with the SmPC.
• Investigate suspected PML immediately and follow lymphocyte counts until recovery after stopping for lymphopenia.

Clinical pharmacology

Diroximel fumarate undergoes rapid presystemic esterase hydrolysis to active monomethyl fumarate and inactive HES. Cytochrome P450 metabolism is not involved; monomethyl fumarate is mainly eliminated as exhaled carbon dioxide.

Formulation and product differences

• The gastro-resistant hard capsule must remain intact.
• Do not directly substitute it with dimethyl fumarate or use them together.

Capsule

Route: Oral

Strengths: 231 mg