Open AccessImmunological evaluation of personalized peptide vaccination monotherapy in patients with castration‐resistant prostate cancer
Author(s) -
Uemura Hirotsugu,
Fujimoto Kiyohide,
Mine Takashi,
Uejima Shigeya,
De Velasco Marco A.,
Hirao Yoshihiko,
Komatsu Nobukazu,
Yamada Akira,
Itoh Kyogo
Publication year - 2010
Publication title -
cancer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.035
H-Index - 141
eISSN - 1349-7006
pISSN - 1347-9032
DOI - 10.1111/j.1349-7006.2009.01459.x
Subject(s) - medicine , prostate cancer , ctl* , immune system , lymph node , peptide vaccine , immunotherapy , prostate specific antigen , antigen , prostate , cancer , oncology , immunology , epitope , cd8
( Cancer Sci 2010; 101: 601–608) We previously reported that personalized peptide vaccine (PPV) therapy in combination with leutenizing hormone‐releasing hormone (LH‐RH) analog and estramustine phosphate in certain cases is safe and capable of inducing both immune responses and clinical responses for metastatic castration‐resistant prostate cancer (CRPC) patients. In the present study, PPV monotherapy was given to CRPC patients. Twenty‐three patients with metastatic CRPC were treated with PPV without any additional treatment modalities, including LH‐RH analogs. Samples were analyzed for peptide‐specific cytotoxic T‐lymphocyte (CTL) precursor analysis and peptide‐reactive IgG. Toxicity and immunological and clinical responses were assessed on a three‐monthly basis. Seventeen patients were available for immunological and clinical evaluation. The vaccines were well tolerated, with grade 3 erythema at injection sites in only one patient. Augmentation of CTL or IgG responses to at least one of the peptides was observed in six of 17 (35%) and 15 of 17 (88%) patients tested, respectively. Among 57 peptides used, 9 and 36 peptides induced CTL and IgG responses, respectively. Delayed‐type hypersensitivity reaction was observed in eight of 17 patients. More than 30% prostate‐specific antigen (PSA) decline was observed in four of 17 patients. Of these, one patient achieved a complete PSA response and another patient showed a partial PSA response with profound shrinking of lymph node metastases and prostate. The overall median survival time was 24 months (range, 5–37 months). These results suggest that PPV monotherapy appears to be safe and capable of inducing peptide‐specific immune responses and clinical responses in CRPC patients. This trial was registered with University Hospital Medical Information Network (UMIN) number R3339.