title: Fludarabine modulates immune response and extends in vivo survival of adoptively transferred CD8 T cells in patients with metastatic melanoma.
abstract: BACKGROUND
  Adoptive T cell therapy involving the use of ex vivo generated antigen-specific cytotoxic T lymphocytes provides a promising approach to immunotherapy. It has become increasingly apparent that anti-tumor efficacy using adoptively transferred T cells is linked to their duration of in vivo persistence and can only be achieved when combined with some form of pre-infusion patient conditioning regimen. An optimal conditioning regimen that provides a positive benefit without serious toxicities has yet to be defined. We have established a unique clinical model that allows for evaluation of a given conditioning regimen on adoptively transferred T cells in humans. In this first-in-human study (FHCRC #1796), we evaluate the use of fludarabine, an FDA-approved reagent with predictable lymphodepleting kinetics and duration of action, as a conditioning regimen that promotes homeostatic upregulation of cytokines and growth signals contributing to in vivo T cell persistence.
  
  
  RESULTS
  We conducted a phase I study in patients with refractory metastatic melanoma. Patients received two infusions of a single tumor-reactive antigen-specific CTL clone expanded to 10(10)/m(2); the first infusion was given without fludarabine conditioning, and the second CTL infusion was given after a course of fludarabine (25 mg/m(2)/dayx5 days). This design permits intra-patient comparison of in vivo T cell persistence pre- and post-fludarabine. Nineteen CTL infusions were administered to ten patients. No serious toxicities were observed. Three of nine evaluable patients experienced minor response or stable disease for periods of 5.8-11.0 months with two additional patients demonstrating delayed disease stabilization. The median overall survival in this heavily pre-treated population was 9.7 months. Fludarabine led to a 2.9 fold improvement in the in vivo persistence of transferred CTL clones from a median of 4.5 days (range 0-38+) to 13.0 days (range 2-63+) (p<0.05). Fludarabine lymphodepletion increased plasma levels of the homeostatic cytokines IL-7 and IL-15. Surprisingly, fludarabine also increased the relative percentage of CD4+ T cells expressing the regulatory protein Foxp3.
  
  
  CONCLUSIONS
  Lymphodepletion with fludarabine enhances transferred T cell persistence but suggest that additional improvements to optimize T cell survival and address regulatory T cells are critical in providing anti-tumor efficacy.
  
  
  BACKGROUND
  ClinicalTrials.gov NCT00317759.
authors.affiliation: Department of Clinical Research, Fred Hutchison Cancer Research Center, Seattle, Washington, United States of America. hwallen@u.washington.edu
authors.forename: Herschel
authors.initials: H
authors.lastname: Wallen
authors.forename: John A
authors.initials: JA
authors.lastname: Thompson
authors.forename: J Zachary
authors.initials: JZ
authors.lastname: Reilly
authors.forename: Rebecca M
authors.initials: RM
authors.lastname: Rodmyre
authors.forename: Jianhong
authors.initials: J
authors.lastname: Cao
authors.forename: Cassian
authors.initials: C
authors.lastname: Yee
mesh_terms: D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology / Q000637:transplantation*; D016207:Cytokines / Q000378:metabolism; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000037:antagonists & inhibitors; D019008:Drug Resistance, Neoplasm; D051858:Forkhead Transcription Factors; D006801:Humans; D016219:Immunotherapy, Adoptive; D008545:Melanoma / Q000276:immunology / Q000556:secondary / Q000628:therapy*; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis / Q000628:therapy; D012878:Skin Neoplasms / Q000276:immunology / Q000473:pathology / Q000628:therapy*; D016896:Treatment Outcome; D014740:Vidarabine / Q000031:analogs & derivatives* / Q000627:therapeutic use
chemical_list: D000970:Antineoplastic Agents; D016207:Cytokines; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D004248:DNA (Cytosine-5-)-Methyltransferases; D014740:Vidarabine; C024352:fludarabine