Multiple Sclerosis — Disease-Modifying Therapy Pregnancy: Contraindicated in pregnancy (may cause congenital malformations; animal reproductive toxicity). Pregnancy must be excluded before initiation in years 1 and 2, with effective contraception during treatment and for at least 6 months after the last dose (males: prevent partner pregnancy for at least 3 months after the last dose). Breast-feeding is contraindicated during treatment and for 1 week after the last dose.

Cladribine

Brand names: Mavenclad

Cladribine is an oral immune-reconstitution therapy used as a disease-modifying treatment for highly active relapsing multiple sclerosis, given as short annual courses.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Multiple sclerosis (oral tablets): recommended cumulative dose 3.5 mg/kg body weight over 2 years, given as 1 treatment course of 1.75 mg/kg per year

Route: Oral

Frequency: Each yearly course = 2 treatment weeks (one at the start of month 1 and one at the start of month 2); each treatment week is 4 or 5 days of a single daily dose of 10 mg or 20 mg (one or two 10 mg tablets) depending on body weight

Max: Cumulative 3.5 mg/kg over 2 years (1.75 mg/kg per yearly course); no more than 2 tablets (20 mg) daily

Neurology context (relapsing MS). Treatment must be initiated and supervised by a physician experienced in the treatment of MS. Dose distributed by body weight per treatment week (SPC Table 1): 40 to <50 kg = 40 mg/week; 50 to <60 kg = 50 mg; 60 to <70 kg = 60 mg; 70 to <80 kg = 70 mg; 80 to <90 kg = 80 mg (week 1)/70 mg (week 2); 90 to <100 kg = 90 mg/80 mg; 100 to <110 kg = 100 mg/90 mg; >=110 kg = 100 mg/100 mg. Use in patients weighing less than 40 kg has not been investigated. Do not take more than 2 tablets daily. Lymphocyte counts must be normal before year 1 and at least 800 cells/mm3 before year 2 (year 2 course may be delayed up to 6 months for lymphocyte recovery; if recovery takes longer than 6 months, discontinue). After the 2 treatment courses, no further cladribine is required in years 3 and 4. Separate from any other oral medicinal product by at least 3 hours on dosing days. Screen for HIV, tuberculosis, and hepatitis B/C before each treatment year. Tablets are uncoated and cytotoxic - swallow immediately; keep hands dry and wash after handling.

Dose adjustments

Renal

Mild renal impairment (CrCl 60-89 mL/min): no dose adjustment needed. Moderate or severe renal impairment (CrCl <60 mL/min): contraindicated (safety and efficacy not established).

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to cladribine or any excipient
HIV infection
Active chronic infection (tuberculosis or hepatitis)
Immunocompromised patients, including those on immunosuppressive or myelosuppressive therapy
Active malignancy
Moderate or severe renal impairment (creatinine clearance <60 mL/min)
Pregnancy and breast-feeding

Side effects

Lymphopenia (very common, ~25.6%)
Herpes zoster / dermatomal herpes zoster and oral herpes
Decrease in neutrophil count
Hypersensitivity (pruritus, urticaria, rash; rarely angio-oedema)
Rash, alopecia

Interactions

Immunosuppressive/myelosuppressive substances (additive haematological effects; not recommended concomitantly)
Other substances affecting the haematological profile
Any other oral medicinal product should be separated by at least 3 hours on cladribine dosing days

Clinical monograph

How it works

As a purine nucleoside analogue it is preferentially incorporated into lymphocyte DNA, producing selective and sustained depletion of B and T lymphocytes with relative sparing of innate immunity.

Prescribing in practice

Pregnancy must be excluded before each course and effective contraception used by both sexes during and for a defined period after treatment, as cladribine is teratogenic and genotoxic.
Screen for and exclude active infection, latent tuberculosis, hepatitis and HIV before starting, and complete necessary vaccinations beforehand given the prolonged lymphopenia.
Because of a possible increased malignancy risk, follow cancer screening recommendations and avoid use in those with active malignancy.

Monitoring

Monitor lymphocyte counts before and during each treatment course and watch for signs of infection and herpes zoster reactivation during the period of lymphopenia.

Counselling the patient

Reliable contraception is essential during and after treatment for the advised interval.
Report fever, persistent cough or other signs of infection promptly.
Attend all blood tests and recommended cancer screening.

Evidence & guidelines

The CLARITY trial showed that oral cladribine reduced relapse rate and disability progression in relapsing-remitting multiple sclerosis, underpinning its NICE-approved use.

Reference: CLARITY trial NEJM 2010; 362(5):416-426; NICE TA616; MHRA 2017; ESC MS Guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

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