Survival analysis of multiple peptide vaccination for the selection of correlated peptides in urological cancers.

Peptide-based cancer vaccines are able to induce strong immune responses, but their clinical results are unsatisfactory. To determine clinically correlated peptides, we analyzed survival data from urological cancer patients treated by personalized peptide vaccination (PPV), in which different multiple peptides were used for individual patients based on human leukocyte antigen (HLA) type and pre-existing immunity. Survival data were obtained from a database of 265 urological cancer patients treated in 5 clinical PPV trials comprising 154 patients with castration-resistant prostate cancer (CRPC) and 111 patients with advanced urothelial cancer (UC). Expression of tumor-associated antigens (TAA) was evaluated in 10 prostate cancer tissues, 4 metastatic lymph nodes from prostate cancer, and 10 UC tissues using immunohistochemical staining. Clinical efficacy of individual peptides for overall survival was evaluated by the Cox proportional hazards regression model. All TAA coding candidate peptides used in PPV treatment were expressed in tumor cells from prostate cancer and UC samples except for p56Lck in both, and prostate-specific antigen (PSA), prostatic acid phosphatase (PAP) and prostate-specific membrane antigen (PSMA) in the UC samples. Patients with the following peptides had a significantly longer survival than patients without the peptides (hazard ratio <1.0, 95% confidence intervals <1.0 and P < .05): SART3-109, PTHrP-102, HNPRL-140, SART3-302 and Lck-90 in CRPC patients, and EGF-R-800, Lck-486, PSMA-624, CypB-129 and SART3-734 in advanced UC patients, respectively. Correlated peptides selected using both survival data and pre-existing immunity for PPV treatment may enhance the clinical benefits for urological cancer patients.

Feasibility study of personalized peptide vaccination for hepatocellular carcinoma patients refractory to locoregional therapies.

Overall survival of patients with hepatocellular carcinoma (HCC) refractory to locoregional therapy is dismal, even following treatment with sorafenib, a multikinase inhibitor. To develop a more efficacious treatment, we undertook a feasibility study of personalized peptide vaccination (PPV) for HCC, in which the peptides were selected from 31 peptide candidates based on the pre-existing immunity. Twenty-six HCC patients refractory to locoregional therapies (cohort 1) and 30 patients refractory to both locoregional and systemic therapies (cohort 2) were entered into the study. There were no severe adverse events related to PPV except for one injection site reaction. At the end of the first cycle of six vaccinations, successful CTL or IgG boosting was observed in 57% or 46% of patients in cohort 1 and in 54% or 52% of patients in cohort 2, respectively. Successful IgG boosting at the end of the second cycle was observed in the majority of patients tested. Median overall survival was 18.7 months (95% confidence interval, 12.2-22.5 months) in cohort 1, and 8.5 months (95% confidence interval, 5.9-12.2 months) in cohort 2. Based on the higher rates of immune boosting and the safety profile of PPV, further clinical studies of PPV would be warranted for patients with HCC refractory to not only locoregional therapy but also both locoregional and systemic therapies. The protocol of this study was registered with the UMIN Clinical Trials Registry (UMIN000001882 and UMIN000003590).

A randomized phase II trial of personalized peptide vaccine with low dose cyclophosphamide in biliary tract cancer.

Since the prognosis of advanced biliary tract cancer (aBTC) still remains very poor, new therapeutic approaches, including immunotherapies, need to be developed. In the current study, we conducted an open-label randomized phase II study to test whether low dose cyclophosphamide (CPA) could improve antigen-specific immune responses and clinical efficacy of personalized peptide vaccination (PPV) in 49 previously treated aBTC patients. Patients with aBTC refractory to at least one regimen of chemotherapies were randomly assigned to receive PPV with low dose CPA (100 mg/day for 7 days before vaccination) (PPV/CPA, n = 24) or PPV alone (n = 25). A maximum of four HLA-matched peptides were selected based on the pre-existing peptide-specific IgG responses, followed by subcutaneous administration. T cell responses to the vaccinated peptides in the PPV/CPA arm tended to be greater than those in the PPV alone arm. The PPV/CPA arm showed significantly better progression-free survival (median time: 6.1 vs 2.9 months; hazard ratio (HR): 0.427; P = 0.008) and overall survival (median time: 12.1 vs 5.9 months; HR: 0.376; P = 0.004), compared to the PPV alone arm. The PPV alone arm, but not the PPV/CPA arm, showed significant increase in plasma IL-6 after vaccinations, which might be associated with inhibition of antigen-specific T cell responses. These results suggested that combined treatment with low dose CPA could provide clinical benefits in aBTC patients under PPV, possibly through prevention of IL-6-mediated immune suppression. Further clinical studies would be recommended to clarify the clinical efficacy of PPV/CPA in aBTC patients.

Personalized peptide vaccination as second-line treatment for metastatic upper tract urothelial carcinoma.

This study investigated the applicability of personalized peptide vaccination (PPV) for patients with metastatic upper tract urothelial cancer (mUTUC) after failure of platinum-based chemotherapy. In this single arm, open-label, phase II clinical trial, patients with mUTUC received PPV at a single institution. Personalized peptide vaccination treatment used a maximum of four peptides chosen from 27 candidate peptides according to human leukocyte antigen types and peptide-reactive IgG titers, for six s.c. injections weekly as one cycle. The safety of PPV, as well as its influence on host immunity and effect on overall survival were assessed. Forty-eight patients were enrolled in this study. Personalized peptide vaccinations were well tolerated without severe adverse events. Median survival time was 7.3 months (95% confidence interval [CI], 5.3-13.1) with 13.0 months for patients receiving combined salvage chemotherapy (95% CI, 5.7-17.5) and 4.5 months for patients receiving PPV alone (95% CI, 1.7-10.1) (P = 0.080). Patients with positive CTL responses showed a significantly longer survival than patients with negative CTL responses (hazard ratio, 0.37; 95% CI, 0.16-0.85; P = 0.019). Multivariate Cox regression analysis showed that lower numbers of Bellmunt risk factors and lower levels of B-cell activating factor were significantly associated with favorable overall survival for patients under PPV treatment. This study indicated that PPV for patients with mUTUC after failure of platinum-based chemotherapy induced substantial peptide-specific CTL responses without severe adverse events and has the potential to prolong survival when combined with salvage chemotherapy. UMIN Clinical Trials Registry ID: 000001854.

Immunological evaluation of peptide vaccination for cancer patients with the HLA -A11+ or -A33+ allele.

The HLA-A11 or -A33 allele is found in approximately 18% or 10% of the Asian population, respectively, but each of which is a minor allele worldwide, and therefore no clinical trials were previously conducted. To develop a therapeutic peptide vaccine for each of them, we investigated immunological responses of advanced cancer patients with the HLA-A11+ /A11+ (n = 18) or -A33+ /A33+ (n = 13) allele to personalized peptide vaccine (PPV) regimens. The primary sites of HLA-A11+/A11+ or -A33+/A33+ patients were the colon (n = 4 or 2), stomach (2 or 3), breast (3 or 2), lung and pancreas (2 or 2), and so on. For PPV, a maximum of four peptides were selected from nine different peptides capable of binding to HLA-A11 and -A33 molecules based on the pre-existing peptide-specific IgG responses. There were no severe adverse events related to PPV. At the end of the first cycle, peptide-specific CTL responses were augmented in 4/12 or 2/9 of HLA-A11+ /A11+ or -A33+ /A33+ patients, while peptide-specific IgG responses were augmented in 6/14 or 4/10 patients, respectively. Clinical responses consisted of four stable diseases and 14 progressive diseases in HLA-A11+ /A11+ patients, versus seven and six in -A33+ /A33+ patients, respectively. Further clinical study of PPV could be recommended because of the safety and positive immunological responses.

Immunological evaluation of personalized peptide vaccination for patients with histologically unfavorable carcinoma of unknown primary site.

The immunological characteristics of carcinoma of unknown primary site (CUP) are not well established due to inclusion of heterogeneous types of metastatic tumors with the absence of any detectable primary site. We evaluated the immune responses in patients with histologically unfavorable CUP during personalized peptide vaccination (PPV). Ten patients with histologically unfavorable CUP who had been treated by PPV after chemotherapy failure were analyzed. In PPV treatment, up to four human leukocyte antigen-matched peptides of a total 31 peptides were selected according to preexisting host immunity before vaccination and administered subcutaneously. Peptides derived from the Lck antigen were most often chosen for use among all patients. CTL responses were increased in 8 of the 10 and 5 of the five patients tested at the end of the first and second PPV cycles, respectively. Increases in humoral responses after vaccination, including IgG, IgG1, IgG3, IgA, and IgM, were observed against not only the vaccinated peptides but also the non-vaccinated peptides. Severe adverse events due to PPV were not observed. Median overall survival was 13.9 months (95 % CI 4.0-22.5 months). PPV activated both cellular and humoral immune responses to short peptides derived from CTL epitopes in the majority of CUP patients. PPV with Lck-derived peptides may be a feasible, new treatment modality for histologically unfavorable CUP patients due to its safety and strong ability to boost immune responses, although its clinical efficacy remains to be investigated in larger-scale trials.

Immunological evaluation of peptide vaccination for cancer patients with the HLA-A26 allele.

To develop a peptide vaccine for cancer patients with the HLA-A26 allele, which is a minor population worldwide, we investigated the immunological responses of HLA-A26(+) /A26(+) cancer patients to four different CTL epitope peptides under personalized peptide vaccine regimens. In personalized peptide vaccine regimens, two to four peptides showing positive peptide-specific IgG responses in pre-vaccination plasma were selected from the four peptide candidates applicable for HLA-A26(+) /A26(+) cancer patients and administered s.c. Peptide-specific CTL and IgG responses along with cytokine levels were measured before and after vaccination. Cell surface markers in PBMCs and plasma cytokine levels were also measured. In this study, 21 advanced cancer patients, including seven lung, three breast, two pancreas, and two colon cancer patients, were enrolled. Their HLA-A26 genotypes were HLA-A26:01 (n = 24), HLA-A26:03 (n = 10), and HLA-A26:02 (n = 8). One, 14, and 6 patients received two, three, and four peptides, respectively. Grade 1 or 2 skin reactions at the injection sites were observed in the majority of patients, but no severe adverse events related to the vaccination were observed. Peptide-specific CTL responses were augmented in 39% or 22% of patients after one or two cycles of vaccination, respectively. Notably, peptide-specific IgG were augmented in 63% or 100% of patients after one or two cycles of vaccination, respectively. Personalized peptide vaccines with these four CTL epitope peptides could be feasible for HLA-A26(+) advanced cancer patients because of their safety and higher rates of immunological responses.

Long-term outcome of elderly patients (75 years or older) with hepatocellular carcinoma.

AIM: The aim of this study was to evaluate the long-term outcome of elderly patients with hepatocellular carcinoma (HCC) aged 75 years or older. METHODS: The study included 422 patients with HCC, who were divided into two age groups: 75 years or older (n = 140) and younger than 75 (n = 282). Outcomes were compared between the two groups. RESULTS: The number of elderly patients treated with supportive care alone (33 patients; 24%) was significantly higher than younger patients (30 patients; 11%, P < 0.01). The 1-, 3-, 5- and 7-year overall survival rates of the elderly patients (81%, 55%, 39% and 23%, respectively) were worse than those of younger patients (85%, 64%, 49% and 36%, respectively, P = 0.042). However, the overall survival rate of the elderly group after excluding 63 patients treated with supportive care alone, was similar to that of the younger group (P = 0.615). Multivariate analysis identified age, total bilirubin levels, albumin levels, serum des-γ-carboxy prothrombin levels, tumor size, number of HCC nodules, vascular invasion, extrahepatic metastasis and treatment modality as independent and significant factors of overall survival. CONCLUSION: Advanced age is a negative prognostic factor in patients with HCC due to the tendency for frequent use of conservative treatment rather than locoregional or surgical treatment.

Radiofrequency ablation combined with transarterial chemoembolization for intermediate hepatocellular carcinoma.

AIM: Radiofrequency ablation therapy (RFA) combined with transarterial chemoembolization (TACE) (combination therapy) is effective for early-stage hepatocellular carcinoma (HCC). The aim of this study was to compare the long-term effects of combination therapy with supportive care alone for intermediate HCC. METHODS: The study included 58 patients with intermediate HCC who received combination therapy (n = 34) or supportive care alone (n = 24). The inclusion criteria were a single nodule of more than 50 mm in diameter or two to three nodules, each measuring more than 30 mm in diameter, or more than three nodules, no vascular invasion and no extrahepatic metastasis. RESULTS: The overall survival rates at 1, 2, 3 and 5 years of the combination therapy group (91%, 65%, 53% and 27%, respectively) were significantly better (P < 0.0001) than those of the supportive care group (42%, 8%, 8% and 0%, respectively). Multivariate analysis identified treatment modality (combination therapy vs supportive care alone: P < 0.0001, risk ratio [RR] = 4.290 [95% confidence interval [CI] = 2.157-8.529]) and serum α-fetoprotein (P = 0.017, RR = 2.318 [95% CI = 1.166-4.610]) as independent and significant factors of overall survival. CONCLUSION: The combination of TACE and RFA is a safe and effective therapy in patients with intermediate HCC.

Evaluation of the Immunological Response of Childhood Cancer Patients Treated with a Personalized Peptide Vaccine for Refractory Soft Tissue Tumor: A Four-Case Series.

This case series aimed to evaluate the peptide-specific immunoglobulin G (IgG) response, clinical effectiveness, and the safety of a personalized peptide vaccine (PPV) in four children with refractory solid cancer. Although the pre-vaccination IgG responses were suppressed, IgG levels against the vaccinated peptides after 12 vaccinations were increased in all three cases who received at least 12 vaccinations. Vaccination-related adverse effects were grade 1 injection-site local skin lesions. One patient, whose diagnosis was relapsed rhabdomyosarcoma, remains in sustained remission after 37 months. Although the pre-vaccination immune response in this patient was low, IgG levels against 2 of the 4 peptide vaccines were increased after the sixth vaccination, followed by a strong increase at the eighteenth vaccination against all 4 peptides, with a >100-fold increase vs. 2 peptides. The remaining three patients exhibited progressive disease and eventually died of their original cancer. The results of the current case series suggest that in cases of childhood solid tumors, when the tumor is controlled at the time of entry PPV may have some consolidation effect. Therefore, PPV could be a new immunotherapy modality for refractory childhood solid tumors.

Immune responses of patients without cancer recurrence after a cancer vaccine over a long term.

The present study aimed to clarify the humoral and cellular immune responses of patients with cancer who experienced no recurrence over a long term after receiving a cancer vaccine. The immune kinetics were investigated in response to a personalized peptide vaccination (PPV) among 44 Japanese patients without an active tumor at entry to the vaccination: Lung adenocarcinoma (n=11); colon (n=18); and breast cancer (n=15) (9, 10, 12, 8 and 5 patients with stage I, II, III and IV recurrences, respectively). The patients' immunoglobulin G (IgG) and cytotoxic T lymphocyte (CTL) activities were measured using a multiplexed Luminex assay and an interferon-γ release assay, respectively. There were no severe adverse events related to the PPV other than a grade III injection site reaction. A potent boost in IgG or CTL at the end of the 1st vaccination cycle was observed in 77% of the patients (n=84). The IgG levels were sustained throughout the follow-up period, whereas the CTL levels declined and were transient. A total of 37 of the 44 patients (84%) had no recurrence, with a median follow-up of 67.6 months (interquartile range, 45.6-82.8 months). Overall, the PPV induced long-term humoral immunity with transient cellular immunity in the majority of patients with cancer without an active tumor at their entry to the PPV.

Investigation of factors associated with reduced clinical benefits of personalized peptide vaccination for pancreatic cancer.

The aim of the present study was to determine the factors associated with reduced clinical benefits of personalized peptide vaccination (PPV) for pancreatic cancer. Phase II PPV clinical trials comprising 309 (8 non-advanced and 301 advanced-stage) patients with pancreatic cancer were conducted. Two to four peptides were selected among a set of 31 different peptides as vaccine candidates for personalized peptide vaccination based on human leukocyte antigen types and preexisting peptide-specific IgG levels, and subcutaneously injected. The selected peptides were subcutaneously injected. Of the 309 patients, 81 failed to complete the 1st PPV cycle due to rapid disease progression, and their median overall survival [2.1 months; 95% confidence interval (CI), 1.8-2.7] was significantly shorter than that of the remaining 228 patients (8.4 months; 95% CI, 8.4-9.9; P<0.01). 'Immune boosting' was defined when IgG levels before vaccination increased more than 2-fold after vaccination. Immune boosting was observed in the majority of patients with PPV irrespective of whether or not they received concomitant chemotherapy. Additionally, patients demonstrating immune boosting exhibited longer survival rates. Although the positive-response rates and peptide-specific IgG levels in pre- and post-vaccination samples differed among the 31 peptides, patients exhibiting immune boosting in response to each of the vaccinated peptides demonstrated longer survival times. Pre-vaccination factors associated with reduced clinical benefits were high c-reactive protein (CRP) levels, high neutrophil counts, lower lymphocyte and red blood cell counts, advanced disease stage and the greater number of chemotherapy courses prior to the PPV treatment. The post-vaccination factors associated with lower clinical benefits were PPV monotherapy and lower levels of immune boosting. In conclusion, pre-vaccination inflammatory signatures, rather than pre- or post-vaccination immunological signatures, were associated with reduced clinical benefits of personalized peptide vaccination (PPV) for pancreatic cancer.

Identification of biomarkers for personalized peptide vaccination in 2,588 cancer patients.

Peptide­based cancer vaccines have failed to provide sufficient clinical benefits in order to be approved in clinical trials since the 1990s. To understand the mechanisms underlying this failure, the present study investigated biomarkers associated with the lower overall survival (OS) among 2,588 patients receiving personalized peptide vaccination (PPV). Survival data were obtained from a database of 2,588 cancer patients including 399 patients with lung, 354 with prostate and 344 with colon cancer. They entered into phase II clinical trials of PPV in which 2 to 4 of 31 warehouse peptides were selected for vaccination on an individual patient basis based on human leukocyte antigen (HLA) class IA­types and pre­existing peptide­specific IgG levels. Higher pre­vaccination neutrophil, monocyte and platelet counts, and lower pre­vaccination lymphocyte and red blood cell counts were inversely associated with OS, with higher sensitivities in the proportions of neutrophils and lymphocytes, respectively. The most potent unfavorable and favorable factors for OS were the median percentage of neutrophils (≥64.8%) or percentage of lymphocytes (≥25.1%) with correlation coefficients (R2) of 0.98 and 0.92, respectively. Higher pre­vaccination levels of c­reactive protein and other inflammatory soluble factors were inversely associated with OS. Pre­vaccination peptide­specific immunity levels had no effect on OS, although lower immune boosting levels were inversely associated with OS. None of the 31 peptides was inversely associated with OS, although a few peptides were positively associated with it. On the whole, the findings of the present study suggested that pre­vaccination inflammatory signatures, but not those of post­vaccination immune induction, were associated with lower clinical benefits of PPV.

Phase I clinical study of a peptide vaccination for hepatitis C virus-infected patients with different human leukocyte antigen-class I-A alleles.

Hepatitis C virus (HCV) infection has a high risk of liver cirrhosis and hepatocellular carcinoma at later stages. We recently identified a peptide derived from the HCV core protein capable of inducing both cellular and humoral responses to nearly all HCV-positive patients in Japan with different human leukocyte antigen (HLA)-class I-A alleles. To assess the safety and immune responses to this novel peptide, we conducted a phase I dose-escalation study of the vaccination for 26 HCV-positive patients who were either non-responders to the interferon-based therapy (n = 23) or refused it (n = 3). The regimen was well tolerated, with no severe vaccine-related toxicity. Twenty-five and 22 patients completed the first and second cycle vaccination (6 and 12 vaccine injections), respectively. After a series of six vaccine injections, peptide-specific CTL activity was augmented in peripheral blood mononuclear cells from 15 of 25 patient samples, with an expected optimal dose of 1 mg peptide. After 12 vaccine injections, peptide-specific IgG production was augmented in plasma from the majority of patients (15 of 22 patients) tested, but not in a dose-dependent fashion. There were two HCV RNA responders with >1 log declines. Among patients whose pre-vaccination levels of alanine aminotransferase and alpha feto-protein exceeded the normal ranges, a <30% decrease was found in 7 of 24 and three of six patients, respectively. Because of its tolerability and higher rate of immune boosting, this protocol is recommended for a phase II study to investigate its clinical efficacy.

A peptide derived from hepatitis C virus (HCV) core protein inducing cellular responses in patients with HCV with various HLA class IA alleles.

C35-44 peptide is a well known HLA-A2-restricted CTL epitope originating from hepatitis C virus (HCV) core protein. It was reported that the majority of HCV positive patients had significant levels of serum IgG specific to this peptide. This study addressed whether C35-44 peptide could induce CTL activity restricted to various HLA class IA alleles or could not. This peptide demonstrated binding activity to HLA-A*2402, -A*2601, -A*3101, and -A*3303 molecules, but not to HLA-A*1101 by means of stabilization assay. This peptide also induced CTL activity restricted to each of them, except HLA-A11(+) peripheral blood mononuclear cells from HCV 1b(+) patients by means of (51)Cr-release assay. With regard to HLA-A2 subtypes, this peptide demonstrated binding activity to HLA-A*0201 and -A*0206, but not to -A*0207 molecules. Furthermore, this peptide induced CTL activity from both the patients and healthy donors with all the HLA class IA molecules mentioned above by means of interferon-gamma production assay. These results may provide new insights for the development of a novel peptide vaccine against HCV compatible with various HLA class IA types.

Development of Lobular Panniculitis Long After Completing the Personalized Peptide Vaccine Therapy.

BACKGROUND Personalized peptide vaccine therapy is regarded as a well-tolerated, safe and effective immunotherapy for patients with advanced cancers. Herein we report an exceptional case of a patient with advanced pancreatic cancer who developed delayed lobular panniculitis at sites corresponding to vaccine injections. CASE REPORT A 64-year-old Japanese female visited our clinic due to thirst and polydipsia; she was diagnosed as having type 2 diabetes. Simultaneously, she was diagnosed as having advanced pancreatic cancer; and a distal pancreatectomy and splenectomy were performed. Afterwards, she received adjuvant chemotherapy with titanium silicate-1 and personalized peptide vaccination using Montanide® ISA-51 by a subcutaneous injection to her abdomen over a total of 30 times. Thirteen months after the vaccine therapy had come to an end, lobular panniculitis appeared at the vaccination sites. At this point, corticosteroid was administered, resulting in significant improvement in the condition of the subcutaneous nodules. CONCLUSIONS This case report highlights the importance of careful patient explanation before initiation of cancer vaccine therapy about the possibilities of lobular panniculitis as an adverse event. It also highlights that it is important that physicians have a greater awareness of the possibility of panniculitis in patients with concerns regarding subcutaneous indurations even long after the end of peptide vaccine therapy.

Identification of new immunogenic peptides in conserved regions of hepatitis C virus (HCV) 1b with the potentiality to generate cytotoxic T lymphocytes in HCV1b(+) HLA-A24(+) patients.

AIM: Hepatitis C virus (HCV) 1b is resistant to standard interferon therapy and has a high risk of developing into hepatocellular carcinoma at the late stage of infection. Therefore, new therapeutic modalities for HCV1b infection must be developed. One approach would be active specific immunotherapy with highly immunogenic HCV1b peptides. METHODS: HCV1b-derived 44 synthetic peptides were selected based on their binding scores to HLA-A24. Peptide-specific IgG were measured by ELISA. Peptide-specific cytotoxic T-lymphocytes (CTLs) were induced in vitro by repeated peptide-stimulation. RESULTS: We identified three novel candidate peptides of HCV1b proteins containing HLA-A24 binding motifs. Each of them had the ability to induce HLA-A24-restricted and peptide-specific CTL activity, and IgGs specific to each of them were detected in the plasma of HCV1b patients. Among these three peptides, a peptide NS5A 2132-2142 was recognized by both cellular and humoral immunities in the majority of blood samples of patients tested. More importantly, the peptide-stimulated peripheral blood mononuclear cells (PBMCs) showed cytotoxicity against cells cotransfected with NS5A and HLA-A2402 genes in an HLA-restricted manner. This is an additional report to our previous study. CONCLUSION: These findings may provide a new insight into the development of a peptide-based specific immunotherapy for HCV1b-infected patients.

Personalized Kampo Medicine Facilitated Both Cytotoxic T Lymphocyte Response and Clinical Benefits Induced by Personalized Peptide Vaccination for Advanced Esophageal Cancer.

We retrospectively evaluated if personalized Kampo medicine (PKM) could facilitate CTL responses and clinical benefits induced by personalized peptide vaccination (PPV), in which HLA-matched vaccines were selected and administered based on the preexisting host immunity, for advanced esophageal cancer (aEC) patients. Among 34 aEC patients entered in the clinical study, 23 patients received PKM and PPV without (n = 12) or with chemotherapy (n = 11), while the remaining 11 patients did not receive PKM but received PPV without (n = 6) or with chemotherapy (n = 5), respectively. Incidence of adverse events was significantly lower or higher in PKM and PPV arm (n = 23) or PPV and chemotherapy arm (n = 16) as compared to that of the counter arm (n = 11 or 18), respectively. Postvaccination PBMCs from the patients undergoing PKM and PPV showed significantly higher CTL responses as compared to the counter arm. The median progression-free survival (PFS) or median survival time (MST) of 34 patients was 2.9 or 7.6 months, respectively. The combination therapy in PPV and PKM arm, but not that in PPV and chemotherapy arm, significantly (P = 0.02) prolonged MST. These results could warrant a next step of prospective clinical study of PKM and PPV for aEC patients.

Identification of hepatitis C virus 1b-derived peptides recognized by both cellular and humoral immune systems in HCV1b(+) HLA-A24(+) patients.

Despite scientific advances, the therapeutic options for hepatitis C virus (HCV) are limited by poor response rates. HCV1b is particularly resistant to standard interferon therapy. The inhibition of the progression of chronic hepatitis and liver cirrhosis and the prevention of the occurrence and recurrence of hepatocellular carcinoma (HCC) are important and thus, there is a need for new therapeutic modalities for HCV1b infection. We, therefore, investigated highly immunogenic peptides and report in this study three novel candidate peptides (at positions 711-720 in envelope 2 protein, 885-893 in non-structural protein 2 and 1716-1724 in non-structural protein 4B) among 35 peptides of conserved regions of HCV1b proteins containing HLA-A24 binding motifs tested. Namely, HCV(711-720), HCV(885-893) and HCV(1716-1724) induced HLA-A24-restricted and peptide-specific cytotoxic T lymphocytes (CTLs) activity in peripheral blood mononuclear cells (PBMCs) from 7, 6 and 5 of 12 patients and also were recognized by plasma of 8, 5 and 7 of 12 HCV1b(+) patients, respectively. These results may provide new insight into the development of a peptide-based specific immunotherapy for HCV1b(+) HLA-A24(+) patients.

Phase II Study of Personalized Peptide Vaccination with Both a Hepatitis C Virus-Derived Peptide and Peptides from Tumor-Associated Antigens for the Treatment of HCV-Positive Advanced Hepatocellular Carcinoma Patients.

Objective. To evaluate safety and immune responses of personalized peptide vaccination (PPV) for hepatitis C virus- (HCV-) positive advanced hepatocellular carcinoma (HCC). Patients and Methods. Patients diagnosed with HCV-positive advanced HCC were eligible for this study. A maximum of four HLA-matched peptides were selected based on the preexisting IgG responses specific to 32 different peptides, which consisted of a single HCV-derived peptide at core protein positions 35-44 (C-35) and 31 peptides derived from 15 different tumor-associated antigens (TAAs), followed by subcutaneous administration once per week for 8 weeks. Peptide-specific cytotoxic T lymphocyte (CTL) and IgG responses were measured before and after vaccination. Results. Forty-two patients were enrolled. Grade 3 injection site skin reaction was observed in 2 patients, but no other PPV-related severe adverse events were noted. Peptide-specific CTL responses before vaccination were observed in only 3 of 42 patients, but they became detectable in 23 of 36 patients tested after vaccination. Peptide-specific IgG responses were also boosted in 19 of 36 patients. Peptide-specific IgG1 responses to both C-35 and TAA-derived peptides could be potentially prognostic for overall survival. Conclusion. Further clinical study of PPV would be warranted for HCV-positive advanced HCC, based on the safety and strong immune induction.