Rumi Gohara

Peptide Vaccination for Patients With Melanoma and Other Types of Cancer Based on Pre-existing Peptide-Specific Cytotoxic T-Lymphocyte Precursors in the Periphery

Identification of antigenic peptides expressed on cancer cells enables us to treat cancer patients with peptide-based immunotherapy. Although optimal protocols for peptide-based vaccines have not yet been elucidated, boosting the immune system could be a better approach than priming the immune system to elicit prompt and potent peptide-specific T-cell responses in cancer patients. With this possibility in mind, the authors undertook a clinical trial in which cancer patients were vaccinated with peptides (maximum 4) after confirmation of pre-existing peptide-specific cytotoxic T-lymphocyte (CTL) precursors in the periphery. Fourteen patients (seven with melanoma and seven with other types of cancer) positive for either HLA-A24 or HLA-A2 were enrolled in this study. Fourteen and 16 peptides were used to screen for HLA-A24+ and HLA-A2+ patients, respectively. The vaccination was well tolerated, and the only adverse effects were local pain and fever. Kinetic analysis revealed that peptide-reactive CTLs increased after peptide vaccination in 7 of 14 patients. Immunoglobulin G (IgG) reactive to the administered peptides was detected in 2 patients before vaccination, although it became detectable in 8 of the other 12 patients after the peptide vaccination. Stable disease for more than 6 months was observed in five patients (one with melanoma and four with other types of cancer); all of these patients showed increased levels of peptide-specific IgG. These results indicate that peptide vaccination of patients showing evidence of pre-existing peptide-specific CTL precursors can be applied in further clinical trials aimed at the treatment of melanoma and other types of cancer.

Phase 1 clinical study of cyclophilin B peptide vaccine for patients with lung cancer.

Cyclophilin B (CypB) possesses two antigenic epitopes (CypB84–92 and CypB91–99) recognized by HLA-A24-restricted and tumor-specific cytotoxic T lymphocytes (CTLs). To determine the safety of CypB-derived peptides and its ability to generate antitumor immune responses, patients with advanced lung cancer received subcutaneous vaccinations of these peptides or their modified peptides. All 16 patients were vaccinated with CypB91–99 or its modified peptide, whereas only two patients were vaccinated with the modified CypB84–92, as immediate-type hypersensitivity to CypB84–92 or its modified peptide was observed in the remaining patients. No severe adverse events were associated with the vaccination. No significant increase in cellular responses to either peptides or tumor cells was observed in the postvaccination PBMCs by the conventional CTL assays in any patients tested. These results suggest that the vaccination of CypB91–99 peptide was safe, but failed to induce objective immune responses at this regimen.

Combination Chemotherapy with Irinotecan and Ifosfamide as Second-Line Treatment of Refractory or Sensitive Relapsed Small Cell Lung Cancer: A Phase II Study

This phase II study was conducted to investigate the efficacy and safety of irinotecan (CPT-11) and ifosfamide as second-line chemotherapy for relapsed small cell lung cancer (SCLC). Eligibility criteria included histologically or cytologically confirmed SCLC, prior chemotherapy including platinum + etoposide, and measurable or evaluable disease. CPT-11 (80 mg/m2) was administered intravenously on days 1, 8 and 15, while ifosfamide (1.5 g/m2) was given on days 1 through 3 every 4 weeks. Thirty-four patients (29 men) with a median age of 69 years (range 42–77) and a median Eastern Cooperative Oncology Group (ECOG) performance status of 1 (range 0–2) were enrolled. The response rate was 52.9% (95% confidence interval: 29.8–64.9%) with 2 complete responses and 16 partial responses. Our analyses of prognostic factors showed risk factors assessed before receiving second-line chemotherapy, which were the number of metastatic sites, performance status and the type of relapse. WHO grade 3–4 neutropenia was recorded in 52.9% of the patients, grade 3 diarrhea in 5.9%. The combination of CPT-11 and ifosfamide demonstrated clinical efficacy in relapsed SCLC with a favorable toxicity profile, particularly for performance status 0–1 and sensitive cases with only one metastatic site.

In Vivo Evidence That Peptide Vaccination Can Induce HLA-DR-Restricted CD4+ T Cells Reactive to a Class I Tumor Peptide

Vaccination with class I tumor peptides has been performed to induce tumor-reactive CD8+ T cells in vivo. However, the kinds of immune responses that vaccination might elicit in patients are not fully understood. In this study we tried to elucidate the mechanisms by which vaccination of class I binding tumor peptides into an HLA-A2+ lung cancer patient elicited dramatic amounts of IgG1 and IgG2 specific to a nonamer peptide, ubiquitin-conjugated enzyme variant Kua (UBE2V)43–51. The UBE2V43–51 peptide contains cysteine at the sixth position. HLA-DR-restricted and UBE2V43–51 peptide-recognizing CD4+ T cells were induced from postvaccination, but not from prevaccination, PBMCs of the cancer patient. In addition, a CD4+ T cell line (UB-2) and its clone (UB-2.3), both of which recognize the UBE2V43–51 peptide in the context of HLA-DRB1*0403 molecules, were successfully established from postvaccination PBMCs. The peptide vaccination increased the frequency of peptide-specific T cells, especially CD4+ T cells. In contrast, mass spectrometric analysis revealed that the vaccinated UBE2V43–51 peptide contained both monomeric and dimeric forms. Both forms, fractionated by reverse phase HPLC, were recognized by UB-2 and UB-2.3 cells. Recognition by these CD4+ T cells was observed despite the addition of a reduction reagent or the fixation of APC. Overall, these results indicate that vaccination with class I tumor peptides can induce HLA-DR-restricted CD4+ T cells in vivo and elicit humoral immune responses, and that a cysteine-containing peptide can be recognized by CD4+ T cells not only as a monomer, but also as a dimer.

Histocompatibility leukocyte antigen-A2402-restricted cytotoxic T lymphocytes recognizing adenocarcinoma in tumor-infiltrating lymphocytes of patients with colon cancer

To cast light on T cell‐mediated specific immunity at the tumor site of colon cancer, we investigated whether interleukin‐2 (IL‐2)‐activated tumor‐infiltrating lymphocytes (TIL) from colon cancer show histocompatibility leukocyte antigen (HLA)‐class I‐restricted cytotoxicity against adenocarcinoma. IL 2‐activated TIL from all four HLA‐A24 patients examined lysed HLA‐A2402+ adenocarcinomas, but not HLA‐A2402 tumors. Those of two of the four cases also lysed HLA‐A2402+ squamous cell carcinomas. CD8+ cytotoxic T lymphocyte (CTL) clones recognizing HLA‐A2402+ adenocarcinomas were established from one CTL line. This CTL line produced IFN‐γ upon recognition of an HLA‐A2402‐ adenocarcinoma transfected with HLA‐A2402 cDNA. These results suggest the presence of HLA‐A2402‐restricted CTL recognizing adenocarcinoma at the tumor site of colon cancer. Furthermore, HLA‐A31‐restricted CTL activity was found in IL‐2‐activated TIL from one of two HLA‐A31+ patients, suggesting the existence of HLA‐class I‐restricted CTL involving an allele other than A24

Phase II Study of Irinotecan and Ifosfamide in Patients with Advanced Non-Small Cell Lung Cancer

Objectives: This phase II study was conducted to investigate the efficacy and safety of irinotecan (CPT-11) and ifosfamide as first-line chemotherapy for advanced non-small cell lung cancer (NSCLC). Methods: Eligibility criteria included histologically or cytologically confirmed NSCLC (stage IIIb or IV), no prior treatment, and measurable or evaluable disease. CPT-11 (80 mg/m2) was administered intravenously on days 1, 8, and 15, while ifosfamide (1.5 g/m2) was given on days 1 through 3 every 4 weeks. Results: Forty-four patients (31 men) with a median age of 65 years (range 43–75) and a median ECOG performance status of 1 (range 0–2) were enrolled. The response rate was 29.5% [95% CI: 16.7–45.2%], with 13 partial responses. The median survival was 12.5 months, the median time to progression was 5.3 months, and the 1 and 2-year survival rates were 52.3 and 11.3%, respectively. Toxicity was generally mild; WHO grade 3–4 neutropenia was recorded in 38.6% of the patients, grade 3 diarrhea in 6.8%, and grade 3–4 nausea/vomiting in 0%. Conclusions: CPT-11 combined with ifosfamide demonstrated anti-tumor activity in advanced NSCLC, with response and survival rates similar to those of cisplatin-based chemotherapy but with a more favorable toxicity profile.