PATIENTS AND METHODS
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- PATIENTS AND METHODS
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Eligible patients were included if they were ≥18 years of age with HLA-A24 and/or HLA-A2 status, as determined by commercially available serological tests (SRL, Tokyo, Japan), and were measurable or assessable and histologically proven to have locally advanced (≥T3, N1) or metastatic (M1) UC that included the urinary bladder and upper urinary tract. All patients received surgical treatment or biopsy and MVAC therapy had failed. Previous chemotherapy with radiation therapy for local treatment of the primary lesion was allowed if completed at least 4 weeks before enrolment. Patients were eligible if their disease had progressed at any time after therapy for advanced or metastatic disease or within 12 months of neoadjuvant or adjuvant treatment. Patients were required to have an Eastern Cooperative Oncology Group performance status of 0 to 1, adequate bone marrow reserve (white blood cell count ≥3000/µL, lymphocyte count ≥1200/µL, platelets ≥75 000/µL and haemoglobin ≥10 g/dL), hepatic function (serum bilirubin ≤1.5 mg/dL), and renal function (serum creatinine ≤1.5 mg/dL), and an estimated life expectancy of at least 12 weeks. Patients with non-malignant systematic disease that precluded them from receiving therapy, including active infection, autoimmune disease, any clinically significant cardiac arrhythmia, or congestive heart failure were not eligible. Patients also had to be negative for hepatitis B and C antigens. Patients with CNS metastases, second primary malignant lesions, or clinically significant pleural effusions or ascites or who had used any investigational agent 1 month before enrolment were not eligible. The study protocol was approved by the institutional ethical review boards of Kitasato University and Kurume University, and conducted in accordance with the Declaration of Helsinki. Written informed consent was obtained from all patients before entering this clinical trial.
The study design was for a non-randomized, open-label, phase I study in patients with advanced or metastatic UC previously treated with MVAC chemotherapy. The treatment was carried out at Kitasato University Hospital and Kurume University Hospital in the outpatients clinic. All immunological analyses were carried out at the Department of Immunology, Kurume University School of Medicine. The peptides used in the present study were prepared by Multiple Peptide Systems (San Diego, CA, USA) under the conditions of Good Manufacturing Practice. The peptide candidates consisted of SART293–101, SART2161–169, SART3109–118, Lck208–216, Lck486–494, Lck488–497, MRP3503–511, MRP31293–1302, PAP213–221, PSA248–257, PSMA624–624, EZH2735–743, EGF-R800–809 and PTH-rP102–111 for patients with HLA-A24, and SART3302–310, SART3309–317, CypB129–138, Lck246–254, Lck422–430, ppMAPkkk294–302, ppMAPkkk432–440, WHSC2103–111, WHSC2141–149, UBE2V43–51, UBE2V85–93, HNRPL140–148, HNRPL501–510, EZH2569–577, PSCA21–30 and EGFR479–488 for patients with HLA-A2 [8,9,13]. These peptides have the ability to induce HLA-A24-restricted or HLA-A2-restricted and tumour-specific CTL activity in peripheral blood mononuclear cells (PBMCs) of cancer patients, and are frequently expressed in various tumour cell lines [14,15,19]. The peptides were supplied in vials containing 3 mg/mL sterile solution for injection. Three milligrams of peptide with sterile saline was added in a 1:1 volume to the Monotide ISA-51 (Seppic, Paris, France), and then mixed in a Vortex mixer (Fisher, Alameda, CA, USA). The ISA51 is suitable for peptide vaccination because peptides solubilized in water phase are sequestered from peptidase-containing body fluid, and slow release of the peptides from the emulsion provides sustained antigenic stimulation . The resulting emulsion (maximum of four peptides per vaccination) was injected subcutaneously into the femoral area, once a week for 12 weeks. This first cycle of treatment consisted of 12 consecutive weekly vaccinations. The cycle was repeated every 12 weeks for as long as the patients agreed to continue and their condition was considered appropriate for vaccination. Toxicity was evaluated in patients who received at least one vaccination, whereas both immunological and clinical evaluations were conducted in those who received more than six vaccinations. Blood samples for studies of immune responses were obtained on weeks 0, 6 and 12 during cycle 1. Supportive care could include blood transfusion and the administration of anti-emetics and analgesics, as appropriate. Further local therapy, including other chemotherapy regimens or radiation therapy, was allowed in patients with advanced disease after assessment of response to this regimen.
To measure peptide-specific CTL precursors, 30 mL peripheral blood was obtained before and after vaccination, and PBMCs were isolated by Ficoll–Conray density gradient centrifugation. Peptide-specific CTL precursors in PBMCs were detected using a previously reported culture method . Briefly, PBMCs (1 × 105 cells/well) were incubated with 10 µm of a peptide in 200 µL of culture medium in U-bottom-type 96-well microculture plates (Nunc, Roskilde, Denmark). The culture medium consisted of 45% RPMI-1640 medium, 45% AIM-V medium (GIBCO BRL, Grand Island, NY, USA), 10% fetal calf serum, 100 U/mL interleukin-2 and 0.1 µm minimal essential medium non-essential amino acid solution (GIBCO BRL). Half of the medium was removed and replaced with a new medium containing a corresponding peptide (20 µm) every 3 days. After incubation for 14 days, these cells were harvested and tested for their ability to produce interferon-γ (IFN-γ) in response to CIR-A2402 (kindly provided by Dr M. Takiguchi, Kumamoto University, Japan) or T2 cells that were pre-loaded with either a corresponding peptide or HIV peptides (RYLRQQLLGI for HLA-A24 and LLFGYPVYV for HLA-A2) as a negative control. The level of IFN-γ was determined by ELISA (limit of sensitivity: 10 pg/mL). All assays were performed in quadruplicate. A two-tailed Student’s t test was employed for the statistical analyses. A well was considered positive when the level of IFN-γ production in response to a corresponding peptide was significantly higher (P < 0.05) than that in response to an HIV peptide, and when the mean amount of IFN-γ production in response to a corresponding peptide was >50 ng/mL compared with that in response to an HIV peptide. The increment of CTL activity was judged as positive if the post-vaccination sample, but not the pre-vaccination sample, showed CTL activity. It was also judged as positive if the level of IFN-γ produced by the post-vaccination (12th) sample was twice as high as that produced by the pre-vaccination sample. Our previous study showed that both increased IgG and a CTL response at least twice that of the vaccinated peptides correlated well with overall survival in patients with castration-resistant prostate cancer .
The levels of anti-peptide IgG were measured using the LuminexTM system, as previously reported . In brief, plasma was incubated with 25 µL peptide-coupled colour-coded beads for 2 h at room temperature on a plate shaker. After incubation, the mixture was washed with a vacuum manifold apparatus and incubated with 100 µL biotinylated goat anti-human IgG (chain-specific) for 1 h at room temperature. The plate was then washed, 100 µL of streptavidin-phycoerythrin was added to the wells, and the mixture was incubated for 30 min at room temperature on a plate shaker. The bound beads were washed three times followed by the addition of 100 µL Tween-PBS into each well. Fifty microlitres of sample was detected using the LuminexTM system. The sample was judged to be positive if the IgG level of the post-vaccination (12th) plasma was twice as high as that of the pre-vaccination plasma. This definition is the same as the CTL response according to our previous results .
Standard indirect immunoperoxidase procedures (ENVISION Kit; DakoCytomation California, Carpinteria, CA, USA) in combination with monoclonal antibodies were used for the detection of infiltrating lymphoid cells (CD45RA and CD45RA, 1:50; Dako, Glostrup, Denmark) . Cells with known positive results were used as positive controls. The primary antibody was omitted for negative controls.
Adverse events were monitored according to the National Cancer Institute Common Terminology Criteria for Adverse Events version 3.0. The clinical response was evaluated based on clinical observations and radiological findings. All known sites of disease were evaluated every 6 weeks by CT scan or MRI examination before and after each cycle. During treatment, blood counts and serum chemistries were performed weekly. Patients were assigned a response category according to the Response Evaluation Criteria in Solid Tumors (RECIST).
Student’s t test was employed for evaluation of immunological assays. Progression-free survival time, overall survival time and response duration were calculated from the first day of peptide vaccination until the date of disease progression or death. The time-to-event endpoint was derived by the Kaplan–Meier method. All patients entering the trial were included in the survival determinations.
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Between July 2007 and April 2009, 10 patients were treated with peptide vaccination at our institutions. Data were collected until December 2009. One patient did not meet the protocol entry criteria because cisplatin-based chemotherapy had not been received before the peptide vaccination. Median age was 71 years (range 44–77 years). Median follow-up time was 8.9 months (mean 12.0 months, range 2.5–29.3 months). Seven patients had bladder UC, two patients had upper urinary tract UC and one patient had bladder and upper urinary tract UC. Seven patients had metastatic disease, of whom five had lymph node metastasis and two had bone metastasis; three patients had locally advanced UC without distant metastasis after MVAC chemotherapy. The clinical characteristics of all entry patients are listed in Table 1.
Table 1. Patient characteristics
|Characteristics||No. of patients|
|HLA typing|| |
| A-2 and A-24||1|
|Primary organ|| |
| Upper urinary tract||2|
|Surgical management|| |
| Radical cystectomy||1|
|Main target tumour|| |
| Lymph node||5|
|Previous treatment|| |
| Chemotherapy and radiation therapy||5|
|Performance status*|| |
For the selection of peptides for the first to 12th vaccinations (the first cycle), pre-vaccination plasma was used to investigate the reactivity to each of the 14 or 16 peptides in the HLA-A24+ (n= 5) or HLA-A2+ patients (n= 4), respectively, followed by selection of the three or four peptides with higher levels of IgG reactivity to each of the peptides in order. For the one patient who was HLA-A24+ and HLA-A2+, all 30 peptides were used for the selection of peptides followed by selection of three peptides from the 14 peptides used for HLA-A24+ patients and the remaining one peptide from the 16 peptides used for HLA-A2+ patients; the peptides chosen had the higher levels of IgG reactivity. A summary of the administered peptides is shown in Table 2. For the second cycle (13th to 24th), the four peptides with highest reactivities were similarly chosen for administration on the basis of the results of screening both PBMCs and plasma. Eight patients received twelve vaccinations and two patients received twenty-four vaccinations without other chemotherapy treatment.
Table 2. Immune responses and clinical outcomes
|Patient no. Clinical stage||Peptide||No. of vaccinations||Cellular response*||Anti-peptide IgG†||Clinical response||PFS (months)||OS (months)||Prognosis|
|Pre-||After 12th||Pre-||After 12th|
| 1 T4N0M1||PAP-213||10||–||NA||1753||NA||PD||1||3||Dead|
| 2 T3bN0M0||SART3-109||24||–||–||193|| 238||PR||22||28||Alive|
|Lck-486||–||–|| 45|| 43|
| 3 TisN2M1||SART3-109||12||–||–|| 48||13 261||PD||3||5||Dead|
|Lck-486||155||–|| 53|| 156|
| 4 T3bN2M0||SART3-109||25||158||137||341||26 423||SD||22||29||Alive|
| 5 T3bN1M0||MAP-432||12||–||113|| 37|| 128||CR||20||20||Dead|
|Lck-422||–||216|| 32|| 25|
|WHSC2-103||57||2558|| 15|| 19|
|UBE2V-85||–||2684|| 20|| 26|
| 6 T3bN1M0||SART3-309||12|| 117||198|| 66|| 61||PD||3||4||Dead|
|CypB-129||–||–|| 99|| 90|
| 7 T4aN2M1||SART3-109||12||–||–||62||25 796||PD||3||9||Dead|
| 8 T4N2M0||Lck-422||23||–||251||47||4 315||SD||3||9||Dead|
| 9 T3N1M0||Lck-422||12||–||–||37||1 395||PD||4||5||Dead|
|UBE2V-43||–||3252||129|| 11 845|
|10 T4N0M0||Lck-208||16||–||193||216|| 232||PD||3||9||Alive|
Representative non-haematological toxicity consisted of dermatological skin reactions including redness and heat at the vaccination site in all patients with grade 1 or 2 toxicity. There were no haematological toxicities or therapy-related deaths.
Peptide-specific cellular and humoral immune activities were measured at 12-week intervals for as long as the samples were available. The peptides used for vaccination and the corresponding immune responses are described in Table 2. One patient (♯1) was not eligible because of rapid disease progression. Among the nine patients tested, the augmentation of peptide-specific CTL responses in PBMCs taken after the 12th vaccination by IFN-γ production was observed in eight patients (♯2, ♯4–10), and the augmentation of IgG responses in plasma taken after the 12th vaccination was also observed in eight patients (♯2–5, ♯7–10). Both CTL and IgG responses were boosted in seven of nine the patients tested and CTL or IgG responses to more than two peptides were observed in four and six tested patients, respectively.
All clinical responses were confirmed by an independent review, and were as follows: one complete response, one partial response, two stable disease and six progressive disease (Table 2). A response was recorded on radiological review in four patients. The remaining six patients had disease progressions. None of the six patients who had disease progression had any response to the peptide vaccinations. At the time of analyses, seven patients had died and all patients had progressed except for one patient who had a complete response but died from a cerebral infarction after complete peptide vaccination. The median progression-free survival was 3.0 months (range 0.5–14.1 months). The median overall survival was 8.9 months (range 2.5–29.3 months). Among the four responders, the median progression-free survival and overall survival were 21 (range 2.7–22.4 months) and 24 (range, 9.0–29.3 months), respectively.
It is of note that two patients (♯2 and ♯5) with locally advanced bladder cancer showed obvious clinical responses on kinetic CT images (Fig. 1). To investigate host–tumour interaction, immunohistochemical staining of the biopsied samples taken at the first visit before MVAC therapy and after the 12th vaccination was performed. Immunohistochemical staining at the time of the first visit before MVAC therapy showed that there were a large numbers of tumour cells in the sample, whereas lymphocyte infiltration was limited in stromal lesions. CD45RA+ naive lymphocytes were rare in the stromal lesions, whereas CD45RO+ activated/memory lymphocytes were found around tumour vessels and stromal lesions, but not in tumour sites (Fig. 2A). Immunohistochemical staining after the 12th vaccination showed that there were very few tumour cells in the sample but many lymphoid cells with lymphoid follicles. CD45RA+ naive lymphocytes were massively observed in lymphoid follicles, while CD45RO+ activated/memory lymphocytes were massively observed not only in lymphoid follicles but also in the other lesions (Fig. 2B). These results suggest that PPV induced infiltration of both CD45RA+ and CD45RO+ cells into tumour sites, which in turn resulted in distraction of most of the tumour cells in this patient.
Figure 1. The kinetic CT images of the tumour lesion of a patient with complete remission (A) and a patient with partial remission (B). The yellow circle indicates the tumour region. Left: pre-vaccination; middle: after the sixth vaccination; right: after the 12th vaccination. Cystoscopy findings of the patient with complete remission after the 12th vaccination showed no visible tumours with negative urinary cytology and post-inflammatory lesions.
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Figure 2. Representative immunohistochemical stainings of both pre-vaccination tumour regions at the first visit before methotrexate, vinblastine, adriamycin and cisplatin therapy (A) and after the 12th vaccination (B); tumour regions with anti-CD45RO and -CD45RA monoclonal antibodies are shown. The magnification was ×100.
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- PATIENTS AND METHODS
- CONFLICT OF INTEREST
No severe adverse events were observed in any of the 10 patients enrolled, although all the patients developed grade 1 or 2 local dermatological reactions at the injection sites. Therefore, in terms of safety, the toxicity of the 12-week regimen of once-weekly PPVs was tolerable and acceptable for patients with MVAC-refractory UC.
With regard to peptide-induced immune reactions, an increase in peptide-specific IFN-γ production in response to at least one of the four vaccinated peptides was observed in most of the post-vaccination PBMCs (eight of nine cases), regardless of the absence (n= 5) or reduced levels (n= 5) of CTL activity in pre-vaccination PBMCs. Boosted CTL activities in response to all four peptides were seen in the post-vaccination samples of the patient with complete remission (♯5). Similarly, an increase of peptide-specific IgGs was observed in the post-vaccination plasma of most patients (eight of nine cases). There were more than 10-fold (n= 7) and 100-fold (n= 6) increases of the IgG levels in the post-vaccination samples, suggesting that clonal expansion of peptide-reactive B cells was induced by this regimen.
These results indicated that both the cellular and humoral responses were well boosted in most patients with UC under this regimen. The profile of positive peptides varied greatly from patient to patient, suggesting that the peptides suitable for use in each patient were different, which is consistent with the previously reported results in other types of cancers [11–15]. This would be because of the heterogeneous nature of the different tumours studied and the immunological diversity of the tumour-reactive CTLs in each patient.
Although cellular immunity is the predominant effector arm of antitumour responses, humoral immunity could also play an important role in host defence against cancer cells . However, the mechanism of antibody production against the small vaccination peptides is unclear. One possible explanation is that pre-existing CD4 T helper type 1 cells specific to the vaccinated peptides recognize peptides loaded on HLA-class IA molecules and so facilitate both CTL induction and IgG production. Alternatively, some peptides may bind both class I and class II HLA and induce activation of CTL and T helper type 1 cells . The biological roles of peptide-reactive IgGs will also need to be clarified in the near future.
This is a phase I trial designed to investigate toxicity and immune responses, but a description of the clinical responses could be important for the next stage of clinical trials. The overall response rate defined by radiological imaging is comparable to those seen in previously reported studies using chemotherapy combinations such as gemcitabine and paclitaxel [27,28]. The median survival time of our 10 patients was somewhat shorter than those reported for patients on chemotherapy regimens [27–29], but the four responders to peptide vaccination showed a median survival time of 24 months, suggesting that PPV has the potential to provide long-term survival in some patients with advanced UC.
In this study, we observed massive infiltration of both CD45RA+ and CD45RO+ cells into tumour sites of a PR patient after PPV, whereas they resided around vessels and connective tissues before the vaccination (at the first visit). We previously reported that PPV induced infiltration of CD45RO+ lymphocytes, but neither CD8+ T cells nor CD20+ B cells, in tumour sites of patients with prostate cancer . In considering CD45RO expression in activated or memory T cells and CD45RA expression in naive T cells , PPV induced infiltration of both CD45RA+ and CD45RO+ cells into tumour sites, which in turn resulted in destruction of most tumour cells in this patient. Further studies with other patients’ samples will be needed to clarify this issue.
The potential efficacy of 12 consecutive weekly vaccinations with PPV in patients with advanced UC merits further investigation based on the safety and boosted immune responses shown herein.