Systematic (IUPAC) name
5-(6-amino-2-chloro-purin-9-yl) -4-fluoro-2- (hydroxymethyl)oxolan-3-ol
Clinical data
Trade names Clolar, Evoltra
Legal status
  • (Prescription only)
Routes of
CAS Registry Number  YesY
ATC code L01
PubChem CID:
DrugBank  YesY
ChemSpider  YesY
Chemical data
Formula C10H11ClFN5O3
Molecular mass 303.677 g/mol

Clofarabine is a purine nucleoside antimetabolite marketed in the US and Canada as Clolar. In Europe and Australia/New Zealand the product is marketed under the name Evoltra. It is FDA-approved for treating relapsed or refractory acute lymphoblastic leukaemia (ALL) in children after at least two other types of treatment have failed. It is not known if it extends life expectancy. Some investigations of effectiveness in cases of acute myeloid leukaemia (AML) and juvenile myelomonocytic leukaemia (JMML) have been carried out. Ongoing trials are assessing its efficacy, if any, for managing other cancers.


  • Side effects 1
  • Contraindications 2
  • Drug interactions 3
  • Delivery 4
  • Results of clinical trials 5
  • Approval 6
  • External links 7

Side effects

  • Tumor lysis syndrome (TLS). Clofarabine quickly kills leukaemia cells in the blood. The body may react to this. Signs include hyperkalemia, hyperuricemia, and hyperphosphatemia. TLS is very serious and can lead to death if it is not treated right away.
  • Systemic inflammatory response syndrome (SIRS): symptoms include fast breathing, fast heartbeat, low blood pressure, and fluid in the lungs.
  • Bone marrow problems (suppression). Clofarabine can stop the bone marrow from making enough red blood cells, white blood cells, and platelets. Serious side effects that can happen because of bone marrow suppression include severe infection (sepsis), bleeding, and anemia.
  • Effects on pregnancy and breastfeeding. Girls and women should not become pregnant or breastfeed during treatment which may harm the baby.
  • Dehydration and low blood pressure. Clofarabine can cause vomiting and diarrhea which may lead to low body fluid (dehydration). Signs and symptoms of dehydration include dizziness, lightheadedness, fainting spells, or decreased urination.
  • Other side effects. The most common side effects are stomach problems (including vomiting, diarrhea, and nausea), and effects on blood cells (including low red blood cells count, low white blood cell count, low platelet count, fever, and infection. Clofarabine can also cause tachycardia and can affect the liver and kidneys.


  • pregnancy or planned pregnancy
  • breast-feeding
  • liver problems
  • kidney problems

Drug interactions

  • nephrotoxic drugs
  • hepatotoxic drugs


  • By intravenous infusion.
  • Dosage is a 2 hour infusion (52 mg/m²) every day for five days. The cycle is repeated every 2 to 6 weeks.
  • Regular blood tests to monitor his or her blood cells, kidney function, and liver function.

Results of clinical trials

Efficacy and safety were demonstrated in a single multi-center trial that enrolled 40 patients aged 2-19. The patients were suffering with relapsed or refractory acute lymphoblastic leukaemia (ALL) (An additional nine patients suffering with blasts or extramedullary disease, an M1 bone marrow, and recovery of peripheral platelet and absolute neutrophil counts; the latter was defined as meeting all criteria for CR except for platelet count recovery. Response rates were determined by an independent response review panel (IRRP).

Six patients (12%) achieved a CR and four patients (8%) achieved a CRp, while five patients (10%) achieved a PR. Of the 15 responding patients, six had post-clofarabine bone marrow transplantation. Hence, response durations could not be determined. In the patients who were not transplanted, the response durations for CR were 43, 50, 82, 93+, and 160+ days; for CRp the response duration was 32 days.

The principal clofarabine toxicities were nausea, vomiting, hematologic toxicity, left ventricular systolic dysfunction; tachycardia may also occur.


Clolar was Food and Drug Administration (FDA) approved 28 December 2004. (Under accelerated approval regulations requiring further clinical studies.)

External links

  • Clofarabine information on Cancerbackup.
  • FDA usage leaflet.
  • homepage.
  • FDA approval notice.