Cladribine
⚠️ The MHRA has reported 3 confirmed cases of progressive multifocal encephalopathy (PML) that developed 6 months to several years after cladribine treatment for haematological conditions.
Always consider this rare but serious risk.
- 📖 Always check BNF or equivalent for UpToDate prescribing advice
- 💊 Allopurinol 300 mg OD (PO for 7 days) may be co-prescribed to reduce tumour lysis risk when treating haematological malignancy
⚙️ Mode of Action
- 🧪 Purine analogue: mimics adenosine nucleoside
- 🔬 Incorporated into DNA → inhibits DNA synthesis & repair → apoptosis of lymphocytes
- 📌 Particularly toxic to B and T lymphocytes → profound immunosuppression
📋 Indication / Dose
- 🎗️ Hairy cell leukaemia
- 🎗️ B-cell chronic lymphocytic leukaemia (CLL)
- 🧠 Highly active relapsing–remitting multiple sclerosis (specialist initiation only)
💊 Dose Range (check BNF/datasheet)
| Name | Starting Dose | Frequency | Route |
|---|
| Cladribine (haematology) | 0.1–0.14 mg/kg/day | Daily × 5–7 days | IV infusion |
| Cladribine (MS – Mavenclad®) | 3.5 mg/kg total cumulative dose over 2 years | Given in 2 annual courses | PO (tablets) |
⚠️ Exact dosing varies by indication – always verify with BNF/SmPC.
🔄 Interactions
- 📖 See BNF for full list
- 💊 Avoid concurrent immunosuppressants (↑ risk of infections)
- ⚠️ Live vaccines contraindicated during and after treatment until immune recovery
⚠️ Cautions
- 📉 Severe immunosuppression – risk of opportunistic infections (HSV, TB, fungal)
- 🧪 Monitor blood counts, renal & hepatic function
- ☢️ Risk of secondary malignancy (esp. long-term use in MS)
🚫 Contraindications
- ❌ Hypersensitivity to cladribine
- ❌ Active chronic infection (e.g. hepatitis, TB, HIV)
- ❌ Pregnancy & breastfeeding (teratogenic)
- ❌ Moderate–severe renal impairment (CrCl < 50 mL/min)
- ❌ Concurrent immunosuppressive/anti-cancer therapy
⚡ Side Effects
- 🤒 Fever, skin rash
- 📉 Myelosuppression → anaemia, neutropenia, thrombocytopenia
- 🧠 Neurotoxicity (rare but serious)
- 🦠 Infections (bacterial, viral, fungal)
- ⚠️ Progressive multifocal encephalopathy (PML) – rare, delayed onset
📚 References
