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Pyrimidine analogues and fluoropyrimidinesIn useDerivative of an earlier drugNeeds review

Cytarabine

Also known as cytosine arabinoside, Ara-C, arabinosylcytosine, Cytosar-U

A synthetic nucleoside related to arabinose nucleosides first found in a marine sponge, given by injection. Its US label covers remission induction in acute non-lymphocytic leukaemia, and use in acute lymphocytic leukaemia and meningeal leukaemia.

From discovery to approval

  1. c. 1959 · Earliest report found

    Reviews describe cytarabine as a semi-synthetic derivative of spongothymidine, an arabinose nucleoside from the Caribbean sponge Cryptotethya crypta. One review says it was made synthetically in 1959 and patented in 1960. Reviews date the sponge isolation to the 1940s or 1950s; a 1951 paper reports sponge nucleosides.[2][3][4][5][6]

  2. 1969-06-17 · FDA regular · 10 years after first description

    Original approval (ORIG-1) of NDA 016793, classed as a Type 1 new molecular entity with priority review in the Drugs@FDA history. The original letter and label are not available there, so the indication at approval is not stated here; the current label lists remission induction in acute non-lymphocytic leukaemia. The type regular is an inference: no accelerated-approval wording was found.[7]

How it works

Kinases convert it to a triphosphate that inhibits DNA polymerase; it kills mainly cells in DNA synthesis (S phase). Some incorporation into DNA and RNA is reported. A deaminase inactivates it.[1]

Where it came from and why

A 2022 review says chemists began to synthesise arabinose nucleosides, including cytarabine, soon after the sponge nucleosides were found, which showed antitumour and antiviral properties. A 1977 review notes araC is useful in some leukaemias and its relative araA against some DNA viruses.

Cancers

  • Acute myeloid leukaemia

    The US label lists remission induction in acute non-lymphocytic leukaemia of adults and children, in combination with other approved anticancer drugs; a 1968 paper is titled as describing the drug as a useful agent in acute leukaemia in adults (title only).[1]

  • Acute lymphocytic leukaemia and blast phase of chronic myelocytic leukaemia

    The label says it has also been found useful in these conditions.[1]

  • Meningeal leukaemia

    The label lists intrathecal use (preservative-free preparations only) for prophylaxis and treatment of meningeal leukaemia.[1]

Family and partners

Drugs derived from it: Ancitabine (cyclocytidine), Enocitabine

Worth knowing

  • The Drugs@FDA history for NDA 016793 lists the original approval on 17 June 1969 (a 2021 review also gives 1969 for FDA marketing).[7]
  • The label states that cytarabine is not effective orally: less than 20 percent of an oral dose is absorbed, and it is rapidly metabolised to the inactive arabinosyluracil.[1]
  • A 1977 review says sensitivity to cytarabine appears to correlate with the ratio of triphosphate formation by a nucleoside kinase to degradation by a deaminase.[6]
  • A 2002 review states that a liposomal multivesicular formulation of cytarabine is approved in several countries for intrathecal treatment of lymphomatous meningitis.[8]
  • A 1951 paper in the Journal of Organic Chemistry reports nucleosides from sponges; reviews date the isolation of spongothymidine variously to the 1940s, 1945 or the 1950s.[5]

On this site

References

  1. Hospira, Inc. Cytarabine injection, solution: prescribing information. DailyMed, set ID e3a8c0e9-19ed-49b7-8464-11e8806f47fd, published 23 October 2026. Source
  2. Cappello E, Nieri P. From Life in the Sea to the Clinic: The Marine Drugs Approved and under Clinical Trial. Life (Basel). 2021;11(12). PubMedDOI
  3. Haque N, Parveen S, Tang T, Wei J, Huang Z. Marine Natural Products in Clinical Use. Mar Drugs. 2022;20(8). PubMedDOI
  4. Merhi F, Dauzonne D, Bauvois B. Implementation of Natural Products and Derivatives in Acute Myeloid Leukemia Management: Current Treatments, Clinical Trials and Future Directions. Cancers (Basel). 2026;18(2). PubMedDOI
  5. Bergmann W, Feeney RJ. Contributions to the study of marine products. XXXII. The nucleosides of sponges. I. J Org Chem. 1951;16(6):981-7. DOI
  6. Cohen SS. The mechanisms of lethal action of arabinosyl cytosine (araC) and arabinosyl adenine (araA). Cancer. 1977;40(1 Suppl):509-18. PubMedDOI
  7. U.S. Food and Drug Administration. Drugs@FDA: Approval date(s) and history, letters, labels, reviews for NDA 016793 (cytarabine). Page read 2026-10-26. Source
  8. Hamada A, Kawaguchi T, Nakano M. Clinical pharmacokinetics of cytarabine formulations. Clin Pharmacokinet. 2002;41(10):705-18. PubMedDOI
  9. Rustum YM, Raymakers RA. 1-Beta-arabinofuranosylcytosine in therapy of leukemia: preclinical and clinical overview. Pharmacol Ther. 1992;56(3):307-21. PubMedDOI
  10. Ellison RR, Holland JF, Weil M, Jacquillat C, Boiron M, Bernard J, et al. Arabinosyl cytosine: a useful agent in the treatment of acute leukemia in adults. Blood. 1968;32(4):507-23. PubMed