Cladribine

Another purine analog, 2-chlorodeoxyadenosine, or cladribine, undergoes reactions similar to those of fl udarabine, and it must be converted to a nucleotide to be cytotoxic. It becomes incorporated at the 3’-terminus of DNA and, thus, hinders elongation. It also affects DNA repair and is a potent inhibitor of ribonucleotide reductase.Resistance may be due to mechanisms analogous to those that affect fludarabine, although cross-resistance is not a problem. Cladribine is effective against hairy cell leukemia, chronic lymphocytic leukemia, and non-Hodgkin lymphoma. It also has some activity against multiple sclerosis. The drug is given as a single, continuous infusion. Cladribine distributes throughout the body, including into the CSF. Severe bone marrow suppression is a common adverse effect, as is fever. Peripheral neuropathy has also been reported. The drug is teratogenic.