CLOLAR® (clofarabine) injection

CLOLAR® (clofarabine) injection

CLOLAR® (clofarabine) injection

Clolar (clofarabine) injection contains clofarabine, a purine nucleoside metabolic inhibitor. The chemical name of clofarabine is 2-chloro-9-(2-deoxy-2-fluoro-β-D-arabinofuranosyl)-9H-purin­6-amine. Its molecular formula is C10H11ClFN5O3 with a molecular weight of 303.68 Daltons.

Clolar (1 mg/mL) is supplied in a 20 mL, single-dose vial. The 20 mL vial contains 20 mg clofarabine formulated in 20 mL unbuffered normal saline (comprised of Water for Injection, USP, and Sodium Chloride, USP). The pH range of the solution is 4.5 to 7.5. The solution is sterile, clear and practically colorless, and is preservative-free.


Clolar  is indicated for the treatment of pediatric patients 1 to 21 years old with relapsed or refractory acute lymphoblastic leukemia after at least two prior regimens.

Mechanism of Action

Clofarabine is sequentially metabolized intracellularly to the 5′-monophosphate metabolite by deoxycytidine kinase and mono- and di-phospho-kinases to the active 5′-triphosphate metabolite. Clofarabine has affinity for the activating phosphorylating enzyme, deoxycytidine kinase, equal to or greater than that of the natural substrate, deoxycytidine. Clofarabine inhibits DNA synthesis by decreasing cellular deoxynucleotide triphosphate pools through an inhibitory action on ribonucleotide reductase, and by terminating DNA chain elongation and inhibiting repair through incorporation into the DNA chain by competitive inhibition of DNA polymerases. The affinity of clofarabine triphosphate for these enzymes is similar to or greater than that of deoxyadenosine triphosphate. In preclinical models, clofarabine has demonstrated the ability to inhibit DNA repair by incorporation into the DNA chain during the repair process. Clofarabine 5′-triphosphate also disrupts the integrity of mitochondrial membrane, leading to the release of the pro-apoptotic mitochondrial proteins, cytochrome C and apoptosis-inducing factor, leading to programmed cell death.

Clofarabine is cytotoxic to rapidly proliferating and quiescent cancer cell types in vitro.


Administer the recommended pediatric dose of 52 mg/m2 as an intravenous infusion over 2 hours daily for 5 consecutive days.

  • Repeat treatment cycles following recovery or return to baseline organ function, approximately every 2 to 6 weeks. Base dosage on the patient’s body surface area (BSA), calculated using the actual height and weight before the start of each cycle. To prevent drug incompatibilities, do not administer other medications through the same intravenous line. Administer subsequent cycles no sooner than 14 days from the starting day of the previous cycle and provided the patient’s ANC is ≥0.75 × 109
  • Provide supportive care, such as intravenous fluids, antihyperuricemic treatment, and alkalinize urine throughout the 5 days of Clolar administration to reduce the effects of tumor lysis and other adverse reactions.
  • Discontinue Clolar if hypotension develops during the 5 days of administration.
  • Monitor renal and hepatic function during the 5 days of Clolar administration
  • Monitor patients taking medications known to affect blood pressure. Monitor cardiac function during administration of Clolar.

Recommended Dosage Reduction for Renal Impairment

Reduce the dose by 50% in patients with creatinine clearance (CrCL) between 30 and 60

mL/min. There is insufficient information to make a dosage recommendation in patients with CrCL less than 30 mL/min

Potential Concomitant Medications and Medications to Avoid

  • Consider prophylactic antiemetic medications as Clolar is moderately emetogenic.
  • Consider the use of prophylactic steroids to mitigate Systemic Inflammatory Response Syndrome (SIRS) or capillary leak syndrome (e.g., hypotension, tachycardia, tachypnea, and pulmonary edema).
  • Minimize exposure to drugs with known renal toxicity during the 5 days of Clolar administration since the risk of renal toxicity may be increased.
  • Avoid concomitant use of medications known to induce hepatic toxicity.


Filter Clolar through a sterile 0.2 micron syringe filter and then dilute with 5% Dextrose Injection, USP, or 0.9% Sodium Chloride Injection, USP, prior to intravenous infusion to a final concentration between 0.15 mg/mL and 0.4 mg/mL. Use within 24 hours of preparation. Parenteral drug products should be visually inspected for particulate matter and discoloration prior to administration, whenever solution and container permit. Store diluted Clolar at room temperature (15°C to 30°C).

Discard unused portion in vial.




Myelosuppression: Clolar causes myelosuppression which may be severe and prolonged. Febrile neutropenia occurred in 55% and non-febrile neutropenia in an additional 10% of pediatric patients in clinical trials. At initiation of treatment, most patients in the clinical studies had hematological impairment as a manifestation of leukemia. Myelosuppression is usually reversible with interruption of Clolar treatment and appears to be dose-dependent. Monitor complete blood counts.

Hemorrhage: Serious and fatal hemorrhage, including cerebral, gastrointestinal and pulmonary hemorrhage, has occurred. The majority of the cases were associated with thrombocytopenia. Monitor platelets and coagulation parameters and treat accordingly.

Infections: Clolar increases the risk of infection, including severe and fatal sepsis, and opportunistic infections. At baseline, 48% of the pediatric patients had one or more concurrent infections. A total of 83% of patients experienced at least one infection after Clolar treatment, including fungal, viral and bacterial infections. Monitor patients for signs and symptoms of infection, discontinue Clolar, and treat promptly.

Tumor Lysis Syndrome: Administration of Clolar may result in tumor lysis syndrome associated with the break-down metabolic products from peripheral leukemia cell death. Monitor patients undergoing treatment for signs and symptoms of tumor lysis syndrome and initiate preventive measures including adequate intravenous fluids and measures to control uric acid.

Systemic Inflammatory Response Syndrome (SIRS) and Capillary Leak Syndrome: Clolar may cause a cytokine release syndrome (e.g., tachypnea, tachycardia, hypotension, pulmonary edema) that may progress to the systemic inflammatory response syndrome (SIRS) with capillary leak syndrome and organ impairment which may be fatal. Monitor patients frequently for these conditions.

Venous Occlusive Disease of the Liver: Patients who have previously received a hematopoietic stem cell transplant (HSCT) are at higher risk for veno-occlusive disease (VOD) of the liver following treatment with clofarabine (40 mg/m2) when used in combination with etoposide (100 mg/m2) and cyclophosphamide (440 mg/m2). Severe hepatotoxic events have been reported in a combination study of clofarabine in pediatric patients with relapsed or refractory acute leukemia. Two cases (2%) of VOD in the monotherapy studies were considered related to study drug. Monitor for and discontinue Clolar if VOD is suspected.

Hepatotoxicity: Severe and fatal hepatotoxicity, including hepatitis and hepatic failure, has occurred with the use of Clolar. Monitor hepatic function, and for signs and symptoms of hepatitis and hepatic failure. Discontinue Clolar immediately for Grade 3 or greater liver enzyme and/or bilirubin elevations.

Enterocolitis: Fatal and serious cases of enterocolitis, including neutropenic colitis, cecitis, and C difficile colitis, have occurred during treatment with clofarabine. This has occurred more frequently within 30 days of treatment, and in the setting of combination chemotherapy. Enterocolitis may lead to necrosis, perforation, hemorrhage or sepsis complications. Monitor patients for signs and symptoms of enterocolitis and treat promptly.

Skin Reactions: Serious and fatal cases of Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) have been reported. Discontinue clofarabine for exfoliative or bullous rash, or if SJS or TEN is suspected.

Embryo-Fetal Toxicity: Based on findings from animal reproductive studies and the drug’s mechanism of action, Clolar can cause fetal harm when administered to a pregnant woman.


Pregnancy: In animal reproduction studies, intravenous administration of clofarabine to pregnant rats and rabbits during organogenesis at doses approximately 0.2 to 1-times the maximum recommended human dose of 52 mg/m2 based on body surface area (BSA) resulted in embryo-fetal mortality, alterations to growth, and structural abnormalities. Advise pregnant women of the potential risk to a fetus. There are no available data on Clolar use in pregnant women to evaluate for a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. Clofarabine should be used during pregnancy only if the potential benefits to the mother outweigh the potential risks, including those to the fetus.

Lactation: There are no data on the presence of clofarabine in human milk, the effects on the breastfed child, or the effects on milk production. Because of the potential for serious adverse reactions in the breastfed child including genotoxicity, advise patients not to breastfeed during treatment with Clolar, and for 2 weeks after the last dose.


Females: Advise female patients to use effective contraception during treatment with Clolar and for 6 months after the last dose.


Males: Based on genotoxicity findings, advise males with female partners of reproductive potential to use effective contraception during treatment with Clolar and for 3 months after the last dose.


Females: Based on findings from animal studies, Clolar may impair female fertility. The reversibility of the effect on fertility is unknown.

Males: Based on findings from animal studies, Clolar may impair male fertility. The reversibility of the effect on fertility is unknown.

Pediatric Use: Safety and effectiveness have been established in pediatric patients 1 to 21 years old with relapsed or refractory acute lymphoblastic leukemia.

Geriatric Use: Safety and effectiveness of Clolar has not been established in geriatric patients aged 65 and older.

Renal Impairment: Reduce the Clolar starting dose by 50% in patients with CrCL of 30 to 60 mL/min. There is insufficient information to make a dosage recommendation in patients with CrCL less than 30 mL/min or in patients on dialysis.

The pharmacokinetics of clofarabine in patients with renal impairment and normal renal function were obtained from a population pharmacokinetic analysis of three pediatric and two adult studies. In patients with CrCL 60 to less than 90 mL/min (N=47) and CrCL 30 to less than 60 mL/min (N=30), the average AUC of clofarabine increased by 60% and 140%, respectively, compared to patients with normal (N=66) renal function (CrCL greater than 90 mL/min).


There were no known overdoses of Clolar. The highest daily dose administered to a human to date (on a mg/m2 basis) has been 70 mg/m2/day × 5 days (2 pediatric ALL patients). The toxicities included in these 2 patients included Grade 4 hyperbilirubinemia, Grade 2 and 3 vomiting, and Grade 3 maculopapular rash.

In a Phase 1 study of adults with refractory and/or relapsed hematologic malignancies, the recommended pediatric dose of 52 mg/m2/day was not tolerated.


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