Preclinical Evaluation of the Short-Term Toxicity of 4-(N)-Docosahexaenoyl 2´, 2´- Difluorodeoxycytidine (DHA-dFdC)

Pharm Res. 2017 Jun;34(6):1224-1232. doi: 10.1007/s11095-017-2139-x. Epub 2017 Mar 28.


Purpose: This study was designed to test the short-term toxicity of DHA-dFdC in a mouse model and its efficacy in a mouse model of leukemia at or below its repeat-dose maximum tolerated dose (RD-MTD).

Method: A repeat-dose dose-ranging toxicity study was designed to determine the tolerability of DHA-dFdC when administered to DBA/2 mice by intravenous (i.v.) injection on a repeat-dose schedule (i.e. injections on days 0, 3, 7, 10, and 13). In order to determine the effect of a lethal dose of DHA-dFdC, mice were injected i.v. with three doses of DHA-dFdC at 100 mg/kg on days 0, 3, and 5 (i.e. a lethal-RD). The body weight of mice was recorded two or three times a week. At the end of the study, major organs (i.e. heart, liver, spleen, kidneys, lung, and pancreas) of mice that received the lethal-RD or RD-MTD were weighed, and blood samples were collected for analyses. Finally, DHA-dFdC was i.v. injected into DBA/2 mice with syngeneic L1210 mouse leukemia cells to evaluate its efficacy at or below RD-MTD.

Results: The RD-MTD of DHA-dFdC is 50 mg/kg. At 100 mg/kg, a lethal-RD, DHA-dFdC decreases the weights of mouse spleen and liver and significantly affected certain blood parameters (i.e. white blood cells, lymphocytes, eosinophils, and neutrophil segmented). At or below its RD-MTD, DHA-dFdC significantly prolonged the survival of L1210 leukemia-bearing mice.

Conclusion: DHA-dFdC has dose-dependent toxicity, affecting mainly spleen at a lethal-RD. At or below its RD-MTD, DHA-dFdC is effective against leukemia in a mouse model.

Keywords: DHA; efficacy; gemcitabine; lethal-repeated dose; leukemia; repeat dose-maximum tolerated dose.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antineoplastic Agents / pharmacology
  • Antineoplastic Agents / toxicity*
  • Cell Line, Tumor
  • Deoxycytidine / analogs & derivatives*
  • Deoxycytidine / pharmacology
  • Deoxycytidine / toxicity*
  • Drug Compounding
  • Female
  • Humans
  • Leukemia L1210 / drug therapy*
  • Maximum Tolerated Dose
  • Mice, Inbred DBA


  • Antineoplastic Agents
  • Deoxycytidine
  • gemcitabine