Chemical Properties
White Crystalline Solid
Originator
Johnson & Johnson (U.S.A.)
Uses
It is a substituted purine nucleoside with antileukemic activity
Definition
ChEBI: 2'-Deoxyadenosine in which the hydrogen at position 2 on the purine ring has been substituted by chlorine. It inhibits the synthesis and repair of DNA, particularly in lymphocytes and monocytes, and is used as an antimetabolite antineoplastic drug for the
treatment of lymphoid malignancies including hairy-cell leukaemia and chronic lymphocytic leukaemia.
Indications
Cladribine (Leustatin) is a synthetic purine nucleoside
that is converted to an active cytotoxic metabolite by
the enzyme deoxycytidine kinase. Like the other purine
antimetabolites, it is relatively selective for both normal
and malignant lymphoid cells and kills resting as well as
dividing cells by mechanisms that are not completely
understood.
The drug is highly active against hairy cell leukemia,
producing complete remissions in more than 60% of patients
treated with a single 7-day course. Activity has
also been noted in other low-grade lymphoid malignancies.
The major side effect is myelosuppression.
Manufacturing Process
Manufacturing process for Cladribine includes these steps as follows: Preparation of 2',3',5'-O-triacetyl guanosine;Preparation of 9-(2',3',5'-O-triacetyl-β-D-ribofuranosyl)-2-amino-6-
chloropurine;Preparation of 9-(2',3',5'-O-triacetyl-β-D-ribofuranosyl)-2,6-dichloropurine;Preparation of 2-chloroadenosine;Preparation of 2-chloro-(3',5'-O-tetraisopropyldisiloxyl)adenosine; Preparation of 2-chloro-2'-O-phenoxythiocarbonyl-(3',5'-O-tetraisopropyldisiloxyl)adenosine; Preparation of 2-chloro-2'-deoxy-(3',5'-O-tetraisopropyldisiloxyl)adenosine; Preparation of 2-chloro-2'-deoxy-adenosine.
Brand name
Leustatin (Ortho Biotech).
Therapeutic Function
Cytostatic
General Description
The drug is available in a 10-mg or 10-mL single-use vialfor IV use. Cladribine is used for chronic lymphocyticleukemia, hairy cell leukemia, and non-Hodgkin’s lymphoma.The mechanism of action of this purine deoxyadenosineanalog involves incorporation into DNA resultingin inhibition of DNA chain extension and inhibitionof DNA synthesis and function. This incorporation intoDNA occurs via the triphosphate metabolite active species.The 2-chloro group on the adenine ring produces resistanceto breakdown by adenosine deaminase. Resistance to the anticancereffects can occur because of decreased expressionof the activating enzyme or overexpression of the catabolicenzymes. Oral bioavailability is variable and averages about50%. The drug crosses the blood-brain barrier; however,CSF concentrations reach only 25% of those in plasma. Thedrug is selectively activated inside the cell, and intracellularconcentrations of phosphorylated metabolites exceed thosein plasma. Toxicities include myelosuppression, neutropenia,immunosuppression, fever, nausea, and vomiting.
Biochem/physiol Actions
Deoxyadenosine analog resistant to adenosine deaminase; antileukemic with immunosuppressive activity
Clinical Use
Antineoplastic agent:
Hairy cell leukaemia (HCL)
Chronic lymphocytic leukaemia (CLL) in patients
who have failed to respond to standard regimens.
Drug interactions
Potentially hazardous interactions with other drugs
Antipsychotics: avoid with clozapine - increased risk
of agranulocytosis.
Antivirals: avoid with lamivudine.
Caution when administering with any other
immunosuppressive or myelosuppressive therapy
Metabolism
Cladribine is extensively distributed and penetrates into
the CNS. Cladribine is phosphorylated within cells by
deoxycytidine kinase to form 2-chlorodeoxyadenosine-
5′-monophosphate which is further phosphorylated to
the diphosphate by nucleoside monophosphate kinase
and to the active metabolite 2-chlorodeoxyadenosine-5′-
triphosphate (CdATP) by nucleoside diphosphate kinase.
CdATP inhibits DNA synthesis and repair, particularly
in lymphocytes and monocytes
There is little information available on the route of
excretion of cladribine in man. An average of 18% of
the administered dose has been reported to be excreted
in urine of patients with solid tumours during a 5-day
continuous intravenous infusion.
