Fludarabine modulates immune response and extends in vivo survival of adoptively transferred CD8 T cells in patients with metastatic melanoma

PLoS One. 2009;4(3):e4749. doi: 10.1371/journal.pone.0004749. Epub 2009 Mar 9.


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.

Methods/findings: 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/significance: 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.

Trial registration: ClinicalTrials.gov NCT00317759.

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 / therapeutic use*
  • CD8-Positive T-Lymphocytes / immunology
  • CD8-Positive T-Lymphocytes / transplantation*
  • Cytokines / metabolism
  • DNA (Cytosine-5-)-Methyltransferases / antagonists & inhibitors
  • Drug Resistance, Neoplasm
  • Forkhead Transcription Factors
  • Humans
  • Immunotherapy, Adoptive*
  • Melanoma / immunology
  • Melanoma / secondary
  • Melanoma / therapy*
  • Middle Aged
  • Neoplasm Recurrence, Local / diagnosis
  • Neoplasm Recurrence, Local / therapy
  • Skin Neoplasms / immunology
  • Skin Neoplasms / pathology
  • Skin Neoplasms / therapy*
  • Treatment Outcome
  • Vidarabine / analogs & derivatives*
  • Vidarabine / therapeutic use


  • Antineoplastic Agents
  • Cytokines
  • FOXP3 protein, human
  • Forkhead Transcription Factors
  • DNA (Cytosine-5-)-Methyltransferases
  • Vidarabine
  • fludarabine

Associated data

  • ClinicalTrials.gov/NCT00317759