Preclinical activity and a pilot phase I study of pacritinib, an oral JAK2/FLT3 inhibitor, and chemotherapy in FLT3-ITD-positive AML

Invest New Drugs. 2020 Apr;38(2):340-349. doi: 10.1007/s10637-019-00786-4. Epub 2019 May 17.

Abstract

Activating FLT3 internal tandem duplication (FLT3-ITD) mutations in acute myeloid leukemia (AML) associate with inferior outcomes. We determined that pacritinib, a JAK2/FLT3 inhibitor, has in vitro activity against FLT3-ITD and tyrosine kinase domain (TKD) mutations. Therefore, we conducted a phase I study of pacritinib in combination with chemotherapy in AML patients with FLT3 mutations to determine the pharmacokinetics and preliminary toxicity and clinical activity. Pacritinib was administered at a dose of 100 mg or 200 mg twice daily following a 3 + 3 dose-escalation in combination with cytarabine and daunorubicin (cohort A) or with decitabine induction (cohort B). A total of thirteen patients were enrolled (five in cohort A; eight in cohort B). Dose limiting toxicities include hemolytic anemia and grade 3 QTc prolongation in two patients who received 100 mg. Complete remission was achieved in two patients in cohort A, one of whom had a minor D835Y clone at baseline. One patient in cohort B achieved morphologic leukemia free state. Seven patients (two in cohort A; five in cohort B) had stable disease. In conclusion, pacritinib, an inhibitor of FLT3-ITD and resistant-conferring TKD mutations, was well tolerated and demonstrated preliminary anti-leukemic activity in combination with chemotherapy in patients with FLT3 mutations.

Keywords: Acute myeloid leukemia; Chemotherapy; Clinical trials; FLT3; Pacritinib.

Publication types

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

MeSH terms

  • Adult
  • Aged
  • Antineoplastic Agents / adverse effects
  • Antineoplastic Agents / pharmacokinetics
  • Antineoplastic Agents / pharmacology
  • Antineoplastic Agents / therapeutic use*
  • Antineoplastic Combined Chemotherapy Protocols / adverse effects
  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use
  • Bridged-Ring Compounds / adverse effects
  • Bridged-Ring Compounds / pharmacokinetics
  • Bridged-Ring Compounds / pharmacology
  • Bridged-Ring Compounds / therapeutic use*
  • Cell Line, Tumor
  • Cell Survival / drug effects
  • Cytarabine / adverse effects
  • Cytarabine / therapeutic use
  • Daunorubicin / adverse effects
  • Daunorubicin / therapeutic use
  • Decitabine / adverse effects
  • Decitabine / therapeutic use
  • Drug Resistance, Neoplasm / drug effects
  • Female
  • Humans
  • Janus Kinase 2 / antagonists & inhibitors*
  • Kaplan-Meier Estimate
  • Leukemia, Myeloid, Acute / drug therapy*
  • Leukemia, Myeloid, Acute / genetics
  • Leukemia, Myeloid, Acute / metabolism
  • Leukemia, Myeloid, Acute / mortality
  • Male
  • Middle Aged
  • Mutation
  • Pilot Projects
  • Protein Kinase Inhibitors / adverse effects
  • Protein Kinase Inhibitors / pharmacokinetics
  • Protein Kinase Inhibitors / pharmacology
  • Protein Kinase Inhibitors / therapeutic use*
  • Pyrimidines / adverse effects
  • Pyrimidines / pharmacokinetics
  • Pyrimidines / pharmacology
  • Pyrimidines / therapeutic use*
  • fms-Like Tyrosine Kinase 3 / antagonists & inhibitors*
  • fms-Like Tyrosine Kinase 3 / genetics
  • fms-Like Tyrosine Kinase 3 / metabolism

Substances

  • 11-(2-pyrrolidin-1-ylethoxy)-14,19-dioxa-5,7,26-triazatetracyclo(19.3.1.1(2,6).1(8,12))heptacosa-1(25),2(26),3,5,8,10,12(27),16,21,23-decaene
  • Antineoplastic Agents
  • Bridged-Ring Compounds
  • Protein Kinase Inhibitors
  • Pyrimidines
  • Cytarabine
  • Decitabine
  • FLT3 protein, human
  • fms-Like Tyrosine Kinase 3
  • JAK2 protein, human
  • Janus Kinase 2
  • Daunorubicin