Phase II Adjuvant Cancer-specific Vaccine Therapy for Esophageal Cancer Patients Curatively Resected After Preoperative Therapy With Pathologically Positive Nodes; Possible Significance of Tumor Immune Microenvironment in its Clinical Effects.

OBJECTIVES: To elucidate the efficacy of adjuvant vaccine monotherapy using 3 Human Leukocyte Antigen (HLA)-A∗24-restricted tumor-specific peptide antigens for ESCC, upregulated lung cancer 10, cell division cycle associated 1, and KH domain-containing protein overexpressed in cancer 1. SUMMARY OF BACKGROUND DATA: ESCC patients with pathologically positive nodes (pN(+)) have a high risk for postoperative recurrence, despite curative resection after preoperative therapy. Subclinical micrometastases are an appropriate target for cancer vaccine. METHODS: This is a non-randomized prospective phase II clinical trial (UMIN000003557). ESCC patients curatively resected after preoperative therapy with pN(+) were allocated into the control and vaccine groups (CG and VG) according to the HLA-A status. One mg each of three epitope peptides was postoperatively injected 10 times weekly followed by 10 times biweekly to the VG. The primary and secondary endpoints were relapse-free survival (RFS) and esophageal cancer-specific survival (ECSS), respectively. RESULTS: Thirty were in the CG and 33 in the VG. No significant difference was observed in RFS between the CG and VG (5-year RFS: 32.5% vs 45.3%), but the recurrence rate significantly decreased with the number of peptides which induced antigen-specific cytotoxic T lymphocytes. The VG showed a significantly higher 5-year ECSS than the CG (60.0% vs 32.4%, P = 0.045) and this difference was more prominent in patients with CD8+ and programmed death-ligand 1 double negative tumor (68.0% vs 17.7%, P = 0.010). CONCLUSIONS: Our cancer peptide vaccine might improve the survival of ESCC patients, which is warranted to be verified in the phase III randomized controlled study.

Cytotoxic T lymphocyte response to peptide vaccination predicts survival in stage III colorectal cancer.

We previously reported a phase I clinical trial of a peptide vaccine ring finger protein 43 (RNF43) and 34-kDa translocase of the outer mitochondrial membrane (TOMM34) combined with uracil-tegafur (UFT)/LV for patients with metastatic colorectal cancer (CRC), and demonstrated the safety and immunological responsiveness of this combination therapy. In this study, we evaluated vaccination-induced immune responses to clarify the survival benefit of the combination therapy as adjuvant treatment. We enrolled 44 patients initially in an HLA-masked fashion. After the disclosure of HLA, 28 patients were in the HLA-A*2402-matched and 16 were in the unmatched group. In the HLA-matched group, 14 patients had positive CTL responses specific for the RNF43 and/or TOMM34 peptides after 2 cycles of treatment and 9 had negative responses; in the HLA-unmatched group, 10 CTL responses were positive and 2 negative. In the HLA-matched group, 3-year relapse-free survival (RFS) was significantly better in the positive CTL subgroup than in the negative-response subgroup. Patients with negative vaccination-induced CTL responses showed a significant trend towards shorter RFS than those with positive responses. Moreover, in the HLA-unmatched group, the positive CTL response subgroup showed an equally good 3-year RFS as in the HLA-matched group. In conclusion, vaccination-induced CTL response to peptide vaccination could predict survival in the adjuvant setting for stage III CRC.

[Survival Benefit by Combined Administration of Cyclophosphamide, Lentinula edodes Mycelia Extract(LEM), and Ganoderma lucidum Mycelia Extract(MAK)in S1018B10 Tumor-Bearing Mice].

Cyclophosphamide(CY)was intraperitoneally administered once a week to C57BL/10mice that had received Rous sarcoma virus(RSV)-induced S1018B10 syngeneic tumor transplantation and in whom tumor diameter exceeded 4.5 mm. Survival was prolonged in a group of mice that also received a mixture of LEM and MAK orally. When splenic cells were cultured under mitomycin C-treated S1018B10 stimulation and the S1018B10-directed cell killing ability was examined, the effector cells were found to be F4/80 - DC/Mф cells. Flow cytometric analysis showed that the proportion of F4/80- DC/Mф cells in the splenic cell culture of the CY+LEM+MAK treatment group was higher than that in the untreated group. The ratio of F4/80+ CD8a+ cells in the CY+LEM+MAK treatment group was lower than that in the untreated group.

[Clinical trial of a seven-peptide vaccine and tegafur-uracil/leucovorin as combination therapy for advanced colorectal cancer].

We conducted a clinical trial of a seven-peptide vaccine in combination with tegafur-uracil/Leucovorin for advanced colorectal cancer. These antigenic peptides were derived from 5 proteins identified as cancer-testis antigens(ring finger protein 43 [RNF43], translocase of outer mitochondrial membrane 34[TOMM34], maternal embryonic leucine zipper kinase[MELK], forkhead box M1[FOXM1], and holliday junction recognition protein[HJURP])and 2 vascular endothelial growth factor receptors(VEGFR1 and VEGFR2). Thirty patients with advanced colorectal cancer were enrolled. We found that 25 patients had Grade 1 injection-site redness/induration and 1 patient had Grade 3 anaphylaxis. Tumor imaging revealed that 3 patients had a partial response (PR), 15 had stable disease(SD)and 12 had progressive disease(PD). This trial showed that treatment with the seven-peptide vaccine and UFT/LV was well tolerated and feasible for advanced colorectal cancer.

[Treatment outcome of peptide vaccination for advanced colorectal cancer].

Complementary DNA( cDNA) microarray technology coupled with laser microdissection has been used to identify human leukocyte antigen (HLA)-A24-restricted epitope peptides as potential targets for cancer vaccination in colorectal cancer patients. These antigenic peptides were derived from 2 different cancer-testis antigens, ring finger protein 43 (RNF43) and translocase of outer mitochondrial membrane 34( TOMM34). We conducted a clinical trial of colorectal cancer-specific peptide( RNF43, TOMM34) vaccines with uracil/tegafur( UFT)+Leucovorin( LV) for the treatment of advanced or recurrent colorectal cancer. The vaccinations were well tolerated without any serious adverse events. There were long-term survivors in the group showing cytotoxic T lymphocyte (CTL) responses against both RNF43 and TOMM34, as well as in the group showing CTL responses against either RNF43 or TOMM34. A new study has been planned to obtain more immunological responses. We started a clinical trial of vaccines against multiple peptides (RNF43, TOMM34, forkhead box protein M1 [FOXM1], maternal embryonic leucine zipper kinase [MELK], holliday junction recognition protein[HJURP], vascular endothelial growth factor receptor 1[VEGFR1], and VEGFR2) for the treatment of advanced or recurrent colorectal cancer.

[Clinical study of Peptide-cocktail vaccination with tegafur-uracil/leucovorin for advanced colorectal cancer].

cDNA microarray technology coupled with laser microdissection has been used to identify human leukocyte antigen(HLA)-A24-restricted epitope peptides as potential targets for cancer vaccination in colorectal cancer patients. These antigenic peptides were derived from 2 different testis cancer antigens, ring finger protein 43(RNF43) and translocase of outer mitochondrial membrane 34(TOMM34). We conducted a clinical trial of vaccines against colorectal cancer specific peptides(RNF43 and TOMM34) with tegafur-uracil/Leucovorin( UFT/LV) for the treatment of advanced or recurrent colorectal cancer. The vaccinations were well tolerated without any adverse events. The highest long-term survival was observed in the group showing cytolytic T-lymphocyte (CTL) responses against both RNF43 and TOMM34, followed by the group showing CTL responses against only RNF43 or only TOMM34. A new study has been planned in order to obtain more immunological responses, and we have started a clinical trial of vaccines against multiple peptides[RNF43, TOMM34, forkhead box protein M1(FOXM1), maternal embryonic leucine zipper kinase(MELK), holliday junction recognition protein(HJURP), vascular endothelial growth factor receptor (VEGFR)1, and VEGFR2]by using UFT/LV for the treatment of advanced or recurrent colorectal cancer.

[New directions in immunotherapy for malignant solid tumors].

Despite advances in treatment modalities, malignant solid tumors remain devastating maladies. Conventional treatment with chemotherapy and radiation is still only partially effective and highly toxic. In the era of increasing knowledge of the molecular biology of tumors and the interaction between the tumor and immune system, the development of targeted agents, including cancer vaccines, has emerged as a promising modality. This article will summarize the recent progress in developing cancer vaccines and immunotherapeutic approaches including adoptive cell transfer and will further review currently ongoing phase II/III studies for malignant solid tumors in the world.

Multicenter, phase II clinical trial of peptide vaccination with oral chemotherapy following curative resection for stage III colorectal cancer.

The safety and immunological responsiveness of a peptide vaccine of ring finger protein 43 and 34-kDa translocase of the outer mitochondrial membrane combined with uracil-tegafur/leucovorin (UFT/LV) was previously demonstrated in metastatic colorectal cancer (CRC) in a phase I clinical trial. To clarify the survival benefit of a peptide vaccine combined with UFT/LV as adjuvant treatment, a phase II clinical trial was conducted involving patients with stage III CRC. All enrolled patients, whose human leukocyte antigen (HLA)-A status was double-blinded, were administered the same regime of a peptide vaccine and UFT/LV chemotherapy. The primary objective of the study was to compare relapse-free survival (RFS) in patients with HLA-A*2402 vs. those without HLA-A*2402. Secondary objectives included comparisons between the two groups regarding overall survival, safety, tolerability and peptide-specific activities of cytotoxic T lymphocytes (CTLs) as measured by the ELISPOT assay. Between December 2009 and December 2014, a total of 46 patients were enrolled to the present study. Three-year RFS was not significantly different between HLA-A*2402 matched and unmatched groups [67.8 vs. 73.6%, respectively; hazard ratio (HR)=1.254, 95% confidence interval (CI): 0.48-4.63; P=0.706]. Three-year RFS was significantly better in patients with positive CTL responses in the HLA-A*2402 matched group compared with those without (85.7 and 33.3%, respectively; HR=0.159, 95% CI: 0.023-0.697; P=0.011). In conclusion, vaccination-induced immune responses combined with UFT/LV were positively associated with survival benefit in patients with HLA-A*2402-positive stage III CRC. Further study is required to clarify whether vaccination-induced immune responses shortly following the initiation of therapy can predict the therapeutic effect and help develop a promising therapeutic strategy for patients with stage III CRC.

H-2 haplotype-dependent serum IL-12 production in tumor-bearing mice treated with various mycelial extracts.

IL-12 is considered to be one of the most important cytokines in anti-cancer therapy. We have demonstrated that substances derived from Basidiomycetes, such as active hexose-correlated compound (AHCC) and PSK induce the production of IL-12. In this study, the MHC dependency of IL-12 production induced by various mycelial extracts, PSK, AHCC and IL-X, was examined. During tumor-bearing, higher serum IL-12 levels were observed in H-2a and H-2b mice as compared to H-2d mice. Concerning the effect of genetic background of mice on response to mycelial extracts, AHCC administration enhanced the serum IL-12 level in H-2b mice but not in H-2d mice, while PSK administration increased the serum IL-12 level in H-2d mice but not in H-2b mice. IL-X, components derived from the same Basidiomycetes, also enhanced the serum IL-12 level in H-2b mice in the early stage of tumor like AHCC, and maintained serum IL-12 at a level higher than the normal value accompanying tumor growth, whereas AHCC did not restore the lowered serum IL-12 level accompanying tumor growth. These results showed that AHCC or IL-X is effective in a genetically Th1-dominant individual whereas PSK is effective in a genetically Th2-dominant individual or Th2-dominant status in advanced cancer patients. So we propose that the suitable combinations of various mycelial extracts may be effective methods of endogenous IL-12 induction for cancer patients of all stages, which is important as a cancer therapy that is relatively free from adverse reactions and which emphasizes the QOL in individual patients.

[The significance of a combination of hepatic artery pump reservoir and new immunotherapy for cancer (NITC) in the treatment of colorectal liver metastasis].

Infusion of anti-cancer agents through a hepatic artery pump reservoir has been reported as a relatively useful means of treating multiple liver metastases but its mechanism of action remains to be clarified. We thought that immune responses might be involved in the mechanism of action of this therapy and attempted to test this assumption in patients with colorectal liver metastases. When the patients were divided into two groups by survival period (the 24-week or longer survival group and the less than 24-week survival group), the 24-week or longer survival group had significantly higher Th1 cytokine levels (p<0.001-0.05) and significantly lower VEGF levels (p<0.01) than the less than 24-week survival group. The survival rate tended to be higher in patients for whom intra-arterial infusion therapy was combined with NITC. These results suggest that the combined therapy induces some kind of immune reaction closely related to tumor size reduction and prolonged patient survival. It seems necessary to compare immune activity during intra-arterial infusion therapy alone with activity during intra-arterial infusion treatment in combination with a new immunotherapy.

[Significance of gefitinib combined with immunotherapy in tumor-bearing mice].

Gefitinib (brand name: Iressa) is a drug approved for molecule-targeting therapy in lung carcinoma patients. There are still many unresolved problems concerning the safety and mechanism of action of this drug. Based on the expectation that this drug combined with immunotherapy would be highly effective, we recently conducted an experiment in tumor-bearing mice. In this experiment, however, the tumor was not significantly reduced in size by this combined therapy. However, since the tumor in this animal model was EGFR positive and because tumor growth tended to be suppressed in mice with higher immune activity, it seems likely that additional studies of this therapy will contribute to identifying the optimum drugs to be combined with gefitinib and the optimum method of dosing that will lead to satisfactory efficacy and safety of gefitinib combined with immunotherapy.

Clinical trial of a 7-peptide cocktail vaccine with oral chemotherapy for patients with metastatic colorectal cancer.

AIM: The combination of a peptide vaccine and tegafur-uracil plus leucovorin (UFT/LV) were evaluated in patients with metastatic colorectal cancer refractory to standard chemotherapy. PATIENTS AND METHODS: Thirty human leukocyte antigen (HLA)-A2402-positive patients were enrolled in the study. In a cycle of treatment, a vaccine comprising of seven synthetic peptides (five tumor antigen-derived and two vascular endothelial growth factor receptor-derived) was injected weekly, and oral chemotherapy, UFT/LV was given daily for four weeks followed by one week of rest. The immunological and clinical responses were evaluated at the end of every five weeks. RESULTS: Notable adverse events included grade 1 injection site redness/induration in 25 patients. Tumor imaging showed partial response in three patients, stable disease in 15, and progressive disease in 12. Survival analysis indicated that patients who exhibited positive cytotoxic T lymphocyte responses to all seven peptides had longer overall survival compared to other patients. CONCLUSION: A 7-peptide vaccine used with UFT/LV is safe and is recommended for further trials in patients with metastatic colorectal cancer.

Phase I clinical trial of a novel peptide vaccine in combination with UFT/LV for metastatic colorectal cancer.

To test the safety and immune responses of a novel peptide vaccine derived from RNF43 (ring finger protein 43) and TOMM34 (34-kDa translocase of the outer mitochondrial membrane) administered in combination with chemotherapy in patients with metastatic colorectal cancer, a phase I clinical trial with 21 HLA-A2402-positive metastatic colorectal cancer patients was conducted. Patients received a weekly peptide vaccine (1 mg of each peptide in incomplete Freund's adjuvant) in combination with oral UFT (300 mg/m(2)/day) and UZEL (75 mg/day) for 4 weeks, followed by 1 week of rest. The protocol consisted of at least two cycles of this regimen. After the 2nd cycle, vaccinations were given biweekly or monthly, depending on the condition of the patient. Clinical responses were judged 10 weeks after the 2nd cycle by performing computed tomography (CT) scans and assessing the cytotoxic T lymphocyte (CTL) responses against RNF43 and TOMM34 in peripheral lymphocytes. The vaccinations were well tolerated without any serious adverse events. CTL responses were induced against both antigens in 8 patients and against one antigen in 12 patients, while 1 patient had no CTL response. The rate of stable disease was 83%. The group with CTL responses against both antigens had the most long-term survivors, followed by the group showing CTL responses against one antigen (p=0.0079). The patients with no CTL responses had the lowest survival. The safety and immunological responsiveness of the present combination therapy suggests that it is clinically beneficial for metastatic colorectal cancer. Further clinical trials are warranted.