Phase I trial of tremelimumab in combination with short-term androgen deprivation in patients with PSA-recurrent prostate cancer

Cancer Immunol Immunother. 2012 Jul;61(7):1137-47. doi: 10.1007/s00262-011-1193-1. Epub 2011 Dec 31.

Abstract

CTLA-4 blockade has demonstrated antitumor efficacy in human clinical trials. The antitumor mechanism is presumably mediated in part by the expansion of tumor-specific T cells. Androgen deprivation, the cornerstone of treatment for patients with metastatic prostate cancer, has been shown to elicit prostate tissue apoptosis and lymphocytic inflammation. We hypothesized that treatment with androgen deprivation, followed by an anti-CTLA-4 antibody, could augment a tumor-specific immune response elicited by androgen deprivation. We report here the results of a phase I trial evaluating a humanized monoclonal antibody targeting CTLA-4, CP-675,206 (tremelimumab), in combination with androgen deprivation using an antiandrogen. Eligible patients were those with PSA-recurrent prostate cancer after primary surgery and/or radiation therapy, not previously treated with androgen deprivation, and without radiographic evidence of metastatic disease. Subjects were treated in two cycles, 3 months apart, in which they received bicalutamide 150 mg daily days 1-28 and tremelimumab on day 29. The primary endpoint of the trial was safety. Secondary endpoints included measures of PSA kinetics and identification of a maximum tolerated dose. Eleven patients were enrolled and completed at least 1 year of follow-up. Dose-limiting toxicities included grade 3 diarrhea and skin rash. No favorable changes in PSA doubling time were observed in a period shortly after completing treatment; however, three patients experienced a prolongation in PSA doubling time detectable several months after completing treatment. The identification of delayed, prolonged favorable changes in serum PSA suggests that future studies could explore this combination in studies evaluating time to disease progression.

Publication types

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

MeSH terms

  • Aged
  • Androgen Antagonists / administration & dosage*
  • Anilides / administration & dosage*
  • Anilides / adverse effects
  • Antibodies, Monoclonal / administration & dosage*
  • Antibodies, Monoclonal, Humanized
  • Antineoplastic Combined Chemotherapy Protocols / administration & dosage*
  • Antineoplastic Combined Chemotherapy Protocols / adverse effects
  • Disease Progression
  • Dose-Response Relationship, Drug
  • Humans
  • Male
  • Middle Aged
  • Nitriles / administration & dosage*
  • Nitriles / adverse effects
  • Prostate-Specific Antigen / blood*
  • Prostate-Specific Antigen / immunology
  • Prostatic Neoplasms / blood
  • Prostatic Neoplasms / drug therapy*
  • Prostatic Neoplasms / pathology
  • Prostatic Neoplasms / surgery
  • Tosyl Compounds / administration & dosage*
  • Tosyl Compounds / adverse effects
  • Treatment Outcome

Substances

  • Androgen Antagonists
  • Anilides
  • Antibodies, Monoclonal
  • Antibodies, Monoclonal, Humanized
  • Nitriles
  • Tosyl Compounds
  • bicalutamide
  • Prostate-Specific Antigen
  • tremelimumab