A pilot study on the safety and efficacy of neoadjuvant chemo‑adoptive immunotherapy for locally advanced rectal cancer

The safety and efficacy of combination therapy of immune cell therapy and chemotherapy [chemo-adoptive immunotherapy (CAIT)] for patients with stage IV or recurrent colorectal cancer have been reported. In the present study, the safety and efficacy of neoadjuvant CAIT were investigated for preoperative therapy of locally advanced rectal cancer. The study included patients with cT3/T4 or cN (+) rectal adenocarcinoma scheduled for curative surgery. Six patients who consented to participate in the current study were selected as subjects. Neoadjuvant CAIT involves administration of activated autologous lymphocytes, αβ T cells, and mFOLFOX6 every 2 weeks for six courses, followed by surgery 4-6 weeks thereafter. Common Terminology Criteria for Adverse Events grade 3 neutropenia was observed in one patient. Neoadjuvant CAIT and curative surgery were performed on all the patients. The confirmed response rate was 67%. Downstaging was confirmed in five patients (83%). Regarding histological effects, two patients were grade 1a and four were grade 2. Regarding immunological reactions, both CD4+ and CD8+ T cell infiltration rates increased after treatment in three patients on tumor-infiltrating lymphocyte (TIL) analysis. In peripheral blood analysis, the total lymphocyte count was maintained in all patients, and the CD8+ T cell count increased by ≥3 times on the pretreatment count in two patients but may not be associated with changes in TILs. During the median postoperative follow-up duration of 24 months, liver and lung metastases occurred in one patient, but all patients survived. In conclusion, neoadjuvant CAIT (αβ T cells + mFOLFOX6) can be safely administered for the treatment of advanced rectal cancer. Verification of the efficacy of comprehensive immune cell therapy, especially the induction of antitumor immunity for the prevention of recurrence, will be maintained. The current study is registered with the Japan Registry of Clinical Trials (jRCT; ID, jRCTc030190248; January 21, 2019).

Effects of adoptive T-cell immunotherapy on immune cell profiles and prognosis of patients with unresectable or recurrent cholangiocarcinoma

The identification of immune cell profiles (ICP) involved in anti-tumor immunity is crucial for immunotherapy. Therefore, we herein investigated cholangiocarcinoma patients (CCA) who received adoptive T-cell immunotherapy (ATI). Eighteen unresectable or recurrent CCA received ATI of αβ T cells alone or combined with chemotherapy. ICP were evaluated by flow cytometry. There were 14 patients with intrahepatic cholangiocarcinoma (iCCA) and four with distal cholangiocarcinoma (dCCA). After one course of treatment, nine iCCA and four dCCA had progressive disease (PD), while five iCCA had stable disease (SD). Median overall survival (OS) was prolonged to 21.9 months. No significant differences were observed in OS between the PD and SD groups of iCCA. The frequency of helper T cells (HT) in iCCA decreased from 70.3% to 65.5% (P = .008), while that of killer T cells (KT) increased from 27.0% to 30.6% (P = .005). dCCA showed no significant changes of immune cells. OS was prolonged in iCCA with increased frequencies of CD3+ T cells (CD3) (P = .039) and αβ T cells (αβ) (P = .039). dCCA showed no immune cells associated with OS. The frequencies of CD3+ T cells and αβ T cells in the PD group for iCCA decreased from 63.5% to 53% (P = .038) and from 61.6% to 52.2% (P = .028), respectively. In the SD group, the frequency of HT decreased from 65.8% to 56.9% (P = .043), whereas that of KT increased from 30.1% to 38.3% (P = .043). In conclusions, ATI affected ICP and prolonged OS. Immune cells involved in treatment effects differed according to the site of cholangiocarcinoma.

Safety evaluation of immune-cell therapy for malignant tumor in the Cancer Immune-cell Therapy Evaluation Group (CITEG)

BACKGROUND AIMS

With the aim of strengthening the scientific evidence of immune-cell therapy for cancer and further examining its safety, in October 2015, our hospital jointly established the Cancer Immune-Cell Therapy Evaluation Group (CITEG) with 39 medical facilities nationwide.

METHODS

Medical information, such as patients' background characteristics, clinical efficacy and therapeutic cell types obtained from each facility, has been accumulated, analyzed and evaluated by CITEG. In this prospective study, we analyzed the adverse events associated with immune-cell therapy until the end of September 2022, and we presented our interim safety evaluation.

RESULTS

A total of 3839 patients with malignant tumor were treated with immune-cell therapy, with a median age of 64 years (range, 13-97 years) and a male-to-female ratio of 1:1.08 (1846:1993). Most patients' performance status was 0 or 1 (86.8%) at the first visit, and 3234 cases (84.2%) were advanced or recurrent cases, which accounted for the majority. The total number of administrations reported in CITEG was 31890, of which 960 (3.0%) showed adverse events. The numbers of adverse events caused by treatment were 363 (1.8%) of 19661 administrations of αβT cell therapy, 9 of 845 administrations of γδT-cell therapy (1.1%) and 10 of 626 administrations of natural killer cell therapy (1.6%). The number of adverse events caused by dendritic cell (DC) vaccine therapy was 578 of 10748 administrations (5.4%), which was significantly larger than those for other treatments. Multivariate analysis revealed that αβT cell therapy had a significantly greater risk of adverse events at performance status 1 or higher, and patients younger than 64 years, women or adjuvant immune-cell therapy had a greater risk of adverse events in DC vaccine therapy. Injection-site reactions were the most frequently reported adverse events, with 449 events, the majority of which were associated with DC vaccine therapy. Among all other adverse events, fever (228 events), fatigue (141 events) and itching (131 events) were frequently reported. In contrast, three patients had adverse events (fever, abdominal pain and interstitial pneumonia) that required hospitalization, although they were weakly related to this therapy; rather, it was considered to be the effect of treatment for the primary disease.

CONCLUSIONS

Immune-cell therapy for cancer was considered to be a safe treatment without serious adverse events.

Efficacy of Adjuvant Immune-cell Therapy Combined With Systemic Therapy for Solid Tumors

BACKGROUND/AIM

The efficacy of adjuvant systemic therapy after surgical resection remains unsatisfactory; therefore, a new treatment strategy is required. We aimed to examine the efficacy of adjuvant immune-cell therapy using activated T lymphocytes with or without dendritic cell vaccination in combination with standard adjuvant systemic therapies in terms of the survival of patients with solid tumors, such as lung, gastric, pancreatic, colorectal, and breast cancers.

PATIENTS AND METHODS

A total of 141 patients with solid tumors were enrolled in this study. The correlation of overall survival and disease-free survival with various clinical factors such as age, sex, performance status score, clinical stage, treatment strategies, and vital status was investigated by univariate and multivariate analyses.

RESULTS

Multivariate analysis revealed that a performance status score of 0 was a favorable prognostic factor in the full analysis set of solid tumors (HR=0.209, 95%CI=0.065-0.676, p=0.0089) and might be the indication for immune-cell therapy in the adjuvant setting.

CONCLUSION

Adjuvant immune-cell therapy combined with other systemic therapies would potentially provide a survival benefit in patients with solid tumors.

Prognostic Factors for Advanced/Recurrent Breast Cancer Treated With Immune-cell Therapy

BACKGROUND/AIM

Advanced/recurrent breast cancer (ARBC) still has a poor prognosis; therefore, new treatment strategies are required. In this retrospective study, we aimed to investigate the efficacy of immune-cell therapy using T lymphocytes activated in vitro with or without dendritic cell vaccination in combination with standard therapies in terms of the survival of patients with ARBC.

PATIENTS AND METHODS

A total of 127 patients with ARBC were enrolled in this study. The correlation between overall survival and various clinical factors of each ARBC subset was examined by univariate and multivariate analyses.

RESULTS

Multivariate analysis demonstrated that performance status (PS) 0, the absence of prior chemotherapy, liver/pleural metastasis, and the presence of combined surgery in ARBC and PS 0 or the absence of liver metastasis in the HR+/HER- subset are indications for immune-cell therapy.

CONCLUSION

A survival benefit could be potentially obtained by a combination of immune-cell therapy with other therapies in ARBC patients.

Abstract 698: Antigen electroporated DC loaded with NKT-cell ligand induces the antigen specific antitumor immunity

Background: Invariant natural killer T (iNKT) cells have been shown as an ideal immunotherapeutic target of which the activation via α-Galactosylceramide (α-Gal) conjugated with the MHC class 1-like CD1d molecule induces both innate and adaptive immune system. With transfection of antigen information, α-Gal loaded CD1d expressing cells can act as a vector to enhance the antigen specific immune responses. Though transfection of antigen information by using antigen coding mRNA or tumor peptide is common, the process of extracting mRNA or identifying tumor peptide is sometimes too complicated. Electroporation (EP) has been reported as a way to induce substances easily into cells. We applied EP as a simple method to deliver the antigen into the vector for iNKT cell activation.In this study, we aimed to show a feasibility of EP as a method to deliver the antigen into α-Gal loaded dendritic cells (DCs), a naturally CD1d expressing vector, in terms of inducing antigen specific antitumor responses and innate immunity.

Methods: DCs were generated from bone marrow of C57BL/6 mice. Ovalbumin (OVA) was electroporated to DCs as a tumor model antigen. To load α-Gal, DCs were cultured with α-Gal for 24 hours before cultured with LPS. We compared the antitumor responses of α-Gal loaded DCs with or without electroporated OVA in C57BL/6 mice. In subcutaneous tumor model, mice were prophylactically administered each type of DCs intravenously followed by subcutaneous injection of EG7, which is OVA induced EL4, thymoma (n = 5). We evaluated the tumor size and the survival rate. We also evaluated the innate immunity which induced by α-Gal loaded DCs with or without electroporated OVA.

Results: With electroporated OVA, tumors didn't grow in mice administered α-Gal loaded DCs whereas tumors in mice administered α-Gal loaded DCs without electroporated OVA aggressively progressed(P < 0.05). In mice administered α-Gal loaded DCs with electroporated OVA, no death was observed during the whole observation period. Survival rate was significantly better for mice administered α-Gal loaded DCs with electroporated OVA than those administered α-Gal loaded DCs without electroporated OVA(P < 0.05). On the other hand, α-Gal loaded DCs with or without electroporated OVA showed no difference in inducing NK cells. But, they either induced more NK cells than α-Gal unloaded DCs(P < 0.05).

Conclusion: α-Gal loaded DCs with electroporated OVA showed significantly higher rate of tumor rejection and longer survival in the mice model inoculated OVA-induced tumor comparing to α-Gal loaded DCs without electroporated OVA. Also, EP didn't impair the ability of inducing innate immunity. EP was feasible as a way to deliver the antigen into the vector which induced antigen specific antitumor responses. We are trying to show the activity of antigen-specific cytotoxic T lymphocytes following the administration of α-Gal loaded DCs with electroporated antigen.

Citation Format: Akihiro Watanabe, Kimihiro Yamashita, Akira Arimoto, Kouta Yamada, Kyosuke Agawa, Takashi Kamigaki, Rishu Takimioto, Yoshihiro Kakeji. Antigen electroporated DC loaded with NKT-cell ligand induces the antigen specific antitumor immunity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 698.

Esophageal cancer responsive to the combination of immune cell therapy and low-dose nivolumab: two case reports

Background

Blocking the programmed death 1 pathway by immune checkpoint inhibitors induces dramatic antitumor activity in patients with malignant tumors. However, the clinical response to immune checkpoint inhibitors remains limited owing to the patients’ immunological status, such as the number of lymphocytes, programmed death ligand 1 expression, and tumor mutation burden. In this study, we successfully treated two patients with advanced esophageal cancer who responded to the combination of adoptive immune cell therapy and a low-dose immune checkpoint inhibitor, nivolumab.

Case presentation

Two Asian (Japanese) patients with advanced esophageal cancer who were resistant to conventional chemoradiation therapy were referred to our hospital for immune therapy. Case 1 was a 66-year-old woman who was diagnosed as having esophageal cancer. She received concurrent chemoradiation therapy and then underwent subtotal esophagectomy, after which she became cancer free. However, she relapsed, and cancer cells were found in the lung and lymph nodes 6 months later. She enrolled in a clinical trial at our institution (clinical trial number UMIN000028756). She received adoptive immune cell therapy twice at a 2-week interval followed by low-dose nivolumab with adoptive immune cell therapy four times at 2-week intervals. A follow-up computed tomography scan showed partial response, with mass reduction of the metastatic lung and mediastinal lesions. Case 2 was a 77-year-old man. He received concurrent chemoradiation therapy with fluoropyrimidine/platinum, and gastroscopy revealed complete remission of esophageal cancer. He was disease free for 5 months, but routine computed tomography revealed multiple metastases in his lungs and lymph nodes. He visited our clinic to receive adoptive immune cell therapy and immune checkpoint inhibitor combination therapy. Radiographic evidence showed continuous improvement of lesions. There was no evidence of severe adverse events during the combination therapy.

Conclusion

The combination of adoptive immune cell therapy and an immune checkpoint inhibitor might be a possible treatment strategy for advanced esophageal cancer.

Trial registration UMIN000028756. Registered 14 September 2017

Effect of adoptive T-cell immunotherapy on immunological parameters and prognosis in patients with advanced pancreatic cancer

BACKGROUND AIMS

Immunotherapy is effective for many types of cancer, but its benefits in advanced pancreatic cancer, which has a poor prognosis, are not well established. In this study, the authors examined the effects of adoptive T-cell immunotherapy (ATI) on immune cell profiles and prognosis in patients with unresectable advanced pancreatic cancer.

METHODS

Seventy-seven patients with unresectable advanced pancreatic cancer were treated with six cycles of αβ T cells alone or in combination with chemotherapy or chemoradiation. Immune cell profiles in peripheral blood samples obtained before and after treatment were comprehensively evaluated by flow cytometry. Furthermore, associations between changes in immune cell frequencies and prognosis were determined.

RESULTS

ATI prolonged survival to 18.7 months compared with previous estimates of 6.2-11.1 months for patients treated with chemotherapy alone. ATI decreased CD3+CD4+CD8- T cell frequency in peripheral blood and increased CD3+CD4-CD8+ T cell frequency. An increase in CD3+ T cells and CD3+TCRγδ- T cells in peripheral blood after treatment was associated with a good prognosis.

CONCLUSIONS

ATI altered the immune profile in peripheral blood, including CD3+CD4-CD8+ T cells, and improved prognosis in pancreatic cancer.

Abstract 6534: Antigen specific antitumor effect induced by antigen-electroporated, natural killer T cell ligand-loaded dendritic cells

Background: Invariant natural killer T (iNKT) cells have been shown as an ideal immunotherapeutic target of which the activation via α-galactosylceramide (α-Gal) conjugated with the MHC class I- like CD1d molecule induces both innate and adaptive immune system. With transfection of antigen information, α-Gal loaded CD1d expressing cells can act as a vector to enhance the antigen specific immune responses. Though transfection of antigen information coded as mRNA is popular, the process of extracting mRNA or identifying tumor peptide is sometimes too complicated. Electroporation (EP) has been reported as a way to induce substances easily into cells. We applied EP to deliver the antigen into the vector for iNKT cell activation just as a simple procedure. In this study, we aimed to show a feasibility of EP as a method to deliver the antigen into α-Gal loaded dendritic cells (DCs), a naturally CD1d expressing vector, in terms of inducing antigen specific antitumor responses.

Methods: DCs were generated from bone marrow of C57BL/6 mice. Ovalbumin (OVA) was electroporated to DCs as a tumor model antigen. To load α-Gal, DCs were cultured with α-Gal for 48 hours. We compared the antitumor responses of α-Gal loaded DCs with or without electroporated OVA in C57BL/6 mice. In subcutaneous tumor model, mice were prophylactically administered each type of DCs intravenously followed by subcutaneous injection of EG7, which is OVA induced EL4, thymoma (n = 5, respectively). We evaluated the tumor size and the survival rate. We also evaluated the antitumor responses of which EP density of OVA can induce efficient antitumor response.

Results: With electroporated OVA, tumors didn't grow in mice administered α-Gal loaded DCs whereas tumors in mice administered α-Gal loaded DCs without electroporated OVA aggressively progressed (P < 0.05). In mice administered α-Gal loaded DCs with electroporated OVA, no death was observed during the whole observation period. Survival rate was significantly better for mice administered α-Gal loaded DCs with electroporated OVA than those administered α-Gal loaded DCs without electroporated OVA (P < 0.05). The α-Gal loaded DCs also induce more memory progenitor cells than control group (P < 0.01).

Conclusion: α-Gal loaded DCs with electroporated OVA showed significantly higher rate of tumor rejection and longer survival in the mice model inoculated OVA-induced tumor comparing to α-Gal loaded DCs without electroporated OVA. EP was feasible as a way to deliver the antigen into the vector which induced antigen specific antitumor responses. We are trying to show the activity of antigen-specific cytotoxic T lymphocytes following the administration of α-Gal loaded DCs with electroporated antigen.

Citation Format: Akihiro Watanabe, Kimihiro Yamashita, Akira Arimoto, Yutaka Sugita, Eiji Fukuoka, Takashi Kamigaki, Rishu Takimoto, Yoshihiro Kakeji. Antigen specific antitumor effect induced by antigen-electroporated, natural killer T cell ligand-loaded dendritic cells [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6534.

Adoptive Immune-Cell Therapy for the Treatment of Neuroendocrine Carcinoma of the Uterine Cervix

BACKGROUND/AIM

We aimed to investigate the efficacy of immune-cell therapy in terms of the survival of patients with neuroendocrine carcinoma of the uterine cervix (NECC), which lacks standardized therapeutic approaches.

PATIENTS AND METHODS

We identified 17 patients who were diagnosed as having NECC and treated with immune-cell therapy. The clinical characteristics of these patients were extracted from their records and their overall survival was measured.

RESULTS

Of the 17 patients, two patients with early-stage NECC without recurrence and three patients with less than four treatments were excluded. The median survival times from the time of diagnosis and from the initial administration of immune-cell therapy were 49.7 and 24.4 months, respectively. The overall survival rates at 1, 2, and 5 years were 63.6%, 38.2%, and 25.5%, respectively. Long-term survival was observed in the patients with distant metastases.

CONCLUSION

The preliminary results of this retrospective study suggested the potential efficacy of immune-cell therapy for NECC.

Prognostic Factors for Endometrial and Cervical Cancers of Uterus Treated With Immune-cell Therapy: A Retrospective Study

BACKGROUND/AIM

In this retrospective study, we aimed to investigate the efficacy of immune-cell therapy using T lymphocytes activated in vitro with or without dendritic cell vaccination in combination with standard therapies in terms of the survival of patients with advanced or recurrent endometrial and cervical cancers of the uterus.

PATIENTS AND METHODS

A total of 187 patients with advanced or recurrent uterine cancer were enrolled in this study. The correlation between overall survival and various clinical factors was examined by univariate and multivariate analyses.

RESULTS

Univariate analysis revealed that the prognosis was improved in uterine cancer patients who received immune-cell therapy without prior chemotherapy or without distant metastasis. Multivariate analysis demonstrated that the absence of prior chemotherapy for endometrial cancer and liver/lung metastasis of cervical cancer are indications for immune-cell therapy.

CONCLUSION

Survival benefit in uterine cancer patients could be potentially obtained by a combination of immune-cell therapy with other therapies.

Changes in Immunological Status in Patients With Metastatic Colorectal Cancer Treated With First-line Chemoimmunotherapy

BACKGROUND/AIM

Chemoimmunotherapy is a promising treatment for various malignant diseases. In this study, we examined whether first-line chemoimmunotherapy using adoptive immune-cell therapy was effective for metastatic colorectal cancer (mCRC).

PATIENTS AND METHODS

The therapeutic efficacy and safety of the standard first-line chemoimmunotherapy with adoptive αβ T cell therapy and bevacizumab were assessed using thirty-two patients with mCRC in our hospital. Immunological status after this chemoimmunotherapy was also evaluated.

RESULTS

The response and disease control rates were 68.8% and 87.5%, respectively. Further, median progression-free and overall survival were 14.2 and 35.3 months. Immunotherapy-associated toxicity was minimal. Significant decrease in the change of monocyte number (p=0.006) and increase in the change of rate of lymphocyte-to-monocyte ratio (p=0.039) were seen in the complete response group.

CONCLUSION

First-line chemoimmunotherapy with adoptive αβ T cell therapy may be useful for mCRC.

Effects of adaptive immune cell therapy on the immune cell profile in patients with advanced gastric cancer

BACKGROUND

Immunotherapy for cancer patients has been the subject of attention in recent years. In this study, we investigated whether αβT-cell therapy causes changes in the host's immune cell profile, and if so, the effect of these changes on prognosis.

METHODS

Peripheral blood mononuclear cells (PBMCs) from 30 gastric cancer patients who had completed one course of αβT-cell therapy were analyzed. The peripheral blood immune cell profile was established using PBMCs by counting the frequency of CD4+ helper T cells, CD8+ killer T cells, regulatory T cells (Tregs), and myeloid-derived suppressor cells and measuring the expression of their surface markers. The changes after treatment and their association with response to treatment were investigated.

RESULTS

Immune cell profiles changed greatly after treatment. The frequency of CD4+ helper T cells decreased, but that of CD8+ killer T cells increased. The frequency of programmed cell death 1 (PD-1)+ effector Tregs increased significantly, but only in the non-progressive disease (non-PD) group, in which it was significantly higher compared with the PD group. Patients in whom the frequency of PD-1+ effector Tregs increased had a significantly better prognosis than those in whom it decreased.

CONCLUSION

Our results suggested that αβT-cell therapy changes the host's immune cell profile, and an increase in PD-1+ effector Tregs may help improve prognosis.

Identification of prognostic factors for γδT cell immunotherapy in patients with solid tumor

BACKGROUND AIMS

Activated γδT cells have been shown to exhibit cytotoxicity against tumor cells. However, the efficacy of γδT cell immunotherapy for a large number of patients with solid tumors remains unclear. In this study, we examined the efficacy of γδT cell immunotherapy using in vitro-activated γδT lymphocytes in combination with standard therapies in terms of the survival of patients with solid tumors, and determined prognostic factor for γδT cell immunotherapy.

METHODS

131 patients enrolled in this study received γδT cell immunotherapy with or without standard therapies. Their overall survival was analyzed by the Kaplan-Meier with log-rank test and Cox regression methods. Immunological analysis was performed by flow cytometry (FCM) before and after six cycles of γδT cell immunotherapy.

RESULTS

Multivariable analysis revealed that patients who showed stable disease (SD) and partial response (PR) to γδT cell immunotherapy showed better prognosis than those with a progressive disease (PD) (P = 0.0269, hazard ratio [HR], 0.410, 95% confidence interval [CI], 0.190-0.901). Furthermore, when immunological parameters were examined by FCM, the high Vγ9/γδT ratio (i.e., the high purity of the Vγ9 cells within the adoptively transferred γδT cells) before treatment was found to be a good prognostic factor for γδT cell immunotherapy (P = 0.0142, HR, 0.328, 95% CI, 0.125-0.801). No serious adverse events were reported during γδT cell immunotherapy.

CONCLUSION

Thus, γδT cell immunotherapy might extend the survival of patients with solid tumors.

Prognostic Factors for Colorectal Cancer Patients Treated With Combination of Immune-cell Therapy and First-line Chemotherapy: A Retrospective Study

BACKGROUND/AIM

In this retrospective study, we aimed to investigate the efficacy of immune-cell therapy using T lymphocytes activated in vitro with or without dendritic cells vaccination (DCs), in combination with 1st-line chemotherapies in terms of the survival of patients with advanced colorectal cancer (CRC).

PATIENTS AND METHODS

A total of 198 patients who were diagnosed with advanced CRC and administered 1st-line chemotherapies were enrolled in this study. The correlation between overall survival (OS) and various clinical factors was examined by univariate and multivariate analyses.

RESULTS

Univariate analyses revealed that the prognosis was improved in CRC patients who received immune-cell therapy with PS 0, bevacizumab (BV), and capecitabine-including regimens (Cap). Finally, multivariate analysis demonstrated that PS=0, and the combination of immune-cell therapy and Cap provided a survival benefit in patients with advanced CRC.

CONCLUSION

The survival benefit could be potentially obtained with better PS by the combination of immune-cell therapy and Cap as a 1st-line setting in patients with CRC.

Significant clinical response of advanced colorectal cancer to combination therapy involving capecitabine and adoptive cell transfer therapy: a case report

Significant clinical response was obtained in a patient with stage IV colorectal cancer (CRC) following combination therapy involving capecitabine and adoptive cell transfer therapy. She had laparoscopic lower anterior resection and left liver metastatic carcinoma resecting in 20th, February, 2017. Capecitabine was used to further treatment for an unresectable hepatic metastasis. The serum level of carcinoembryonic antigen (CEA) was increased significantly after dropped temporarily. Since then, the patient took the adoptive cell transfer therapy at the same time. αβT cells and NK cells were injected intravenously into the patient. After the first transfusion with αβT cells, the tumor biomarker, CEA, dropped obviously from 14.7 to 6.1 ng/mL. And it came to 1.9 ng/mL after four times treatment, which was back into normal range (<5 ng/mL). Flow cytometry (FCM) was used to reveal the detailed immunological status of this patient before and after adoptive cell transfer therapy. With 19-month follow-up, neither recurrence or complication was founded. Combination therapy involving adoptive immunotherapy and capecitabine may be the potential method for advanced CRC with less complication.

Abstract 5642: Electroporation as a feasible method for antigen delivering into vectors loaded with NKT cell ligand

Background: Invariant natural killer T (iNKT) cells have been shown as an ideal immunetherapeutic target of which the activation via α-Galactosylceramide (α-GalCer) conjugated with the MHC class I-like CD1d molecule induces both the innate and adaptive immune system. With transfection of antigen-coding mRNA, α-GalCer loaded CD1d-expressing cells can act as a vector to enhance the antigen-specific immune responses. However, the method using the transfection of antigen-coding mRNA is sometimes too complicated. Electroporation (EP) has been reported as a way to induce substances easily into cells. We applied EP as a simple method to deliver the antigen into the vector for iNKT activation. In this study, we aimed to show the feasibility of EP as a method to deliver the antigen into α-GalCer loaded DCs, a naturally CD1d-expressing vector, in terms of inducing antigen-specific antitumor responses.

Methods: DCs were generated from bone marrow of C57BL/6 mice. Ovalbumin (OVA) was electroporated to DCs as a tumor model antigen. To load α-GalCer, DCs were cultured with α-GalCer for 48 hours. We compared the antitumor responses of α-GalCer loaded DCs with or without electroporated OVA in C57BL/6 mice. Mice were prophylactically administered each type of DCs intravenously followed by subcutaneous injection of EG7, which is OVA induced EL4, thymoma (n = 5, respectively). We evaluated the tumor size and the survival rate.

Results: With electroporated OVA, tumors did not grow in mice administered α-GalCer loaded DCs whereas tumors in mice administered α-GalCer loaded DCs without electroporated OVA aggressively progressed (tumor size on day 28 after tumor inoculation; 3 ± 3 vs 4176 ± 1571 mm3, P &lt; 0.05). In mice administered α-GalCer loaded DCs with electroporated OVA, no death was observed during the whole observation period. Survival rate was significantly better for mice administered α-GalCer loaded DCs with electroporated OVA than those administered α-GalCer loaded DCs without electroporated OVA (P &lt; 0.05).

Conclusion: α-GalCer loaded DCs with electroporated OVA showed significantly higher rate of tumor rejection and longer survival in the mice model inoculated OVA-induced tumor compared to α-GalCer loaded DCs without electroporated OVA. EP was feasible as a way to deliver the antigen into the vector, which induced antigen-specific antitumor responses. We are trying to show the activity of antigen-specific cytotoxic T lymphocytes following the administration of α-GalCer loaded DCs with electroporated antigen.

Citation Format: Akira Arimoto, Masayasu Nishi, Kimihiro Yamashita, Yutaka Sugita, Eiji Fukuoka, Tomoko Tanaka, Takashi Kamigaki, Rishu Takimoto, Yoshihiro Kakeji. Electroporation as a feasible method for antigen delivering into vectors loaded with NKT cell ligand [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5642.

Prognostic Factors for Pancreatic Cancer Patients Treated with Immune-cell Therapy

BACKGROUND/AIM

The past 17 years, immune-cell therapy has been administered to 990 patients with advanced or recurrent pancreatic adenocarcinoma and 50 patients with curatively resected pancreatic adenocarcinoma.

MATERIALS AND METHODS

The correlation between overall survival (OS) and various factors including sex, age, performance status (PS), distant metastasis, chemotherapy, radiotherapy, and type of immune-cell therapy were evaluated by univariate and multivariate analyses.

RESULTS

The median OS of advanced or recurrent pancreatic cancer was 5.8 months, and the prognosis was improved in pancreatic cancer patients who received immune-cell therapy with PS scores of 0-1 [hazard risk (HR)=0.56; 95% confidence interval (CI)=0.46-0.68; p<0.0001], chemotherapy (HR=0.68; 95%CI=0.54-0.87; p=0.002), or radiotherapy (HR=0.76; 95%CI=0.63-0.93; p=0.006). Multivariate analysis demonstrated that distant metastasis indicated a poor prognosis for pancreatic cancer patients that were administered immune-cell therapy (HR=1.62; 95%CI=1.37-1.93; p<0.0001). Additionally, the combined immune-cell therapy with αβ T cell and dendritic cell (DC) vaccine provided a survival benefit in advanced or recurrent pancreatic cancer patients (HR=0.69; 95%CI=0.57-0.83; p<0.0001).

CONCLUSION

A survival benefit could be potentially obtained with better PS by the combination of αβ T cell therapy, DC vaccine therapy, and chemotherapy at an early stage in pancreatic cancer.

Extensive first-principles molecular dynamics study on Li encapsulation into C60 and its experimental confirmation

The aim of increasing the production ratio of endohedral C₆₀ by impinging foreign atoms against C₆₀ is a crucial matter of the science and technology employed towards industrialization of these functional building block materials. Among these endohedral fullerenes, Li⁺@C₆₀ exhibits a wide variety of physical and chemical phenomena and has the potential to be applicable in areas spanning the medical field to photovoltaics. However, currently, Li⁺@C₆₀ can be experimentally produced with only ∼1% ratio using the plasma shower method with a 30 eV kinetic energy provided to the impinging Li⁺ ion. From extensive first-principles molecular dynamics simulations, it is found that the maximum production ratio of Li⁺@C₆₀ per hit is increased to about 5.1% (5.3%) when a Li⁺ ion impinges vertically on a six-membered ring of C₆₀ with 30 eV (40 eV) kinetic energy, although many C₆₀ molecules are damaged during this collision. On the contrary, when it impinges vertically on a six-membered ring with 10 eV kinetic energy, the production ratio remains at 1.3%, but the C₆₀ molecules are not damaged at all. On the other hand, when the C₆₀ is randomly oriented, the production ratio reduces to about 3.7 ± 0.5%, 3.3 ± 0.5%, and 0.2 ± 0.03% for 30 eV, 40 eV, and 10 eV kinetic energy, respectively. Based on these observations we demonstrate the possibility of increasing the production ratio by fixing six-membered rings atop C₆₀ using the Cu(111) substrate or UV light irradiation. In order to assess the ideal experimental production ratio, the ⁷Li solid NMR spectroscopy measurement is also performed for the multilayer randomly oriented C₆₀ sample irradiated by Li⁺ using the plasma shower method combined with inductively coupled plasma atomic emission spectroscopy (ICP-AES). Time-of-flight mass spectroscopy measurements are also performed to cross check whether Li⁺@C₆₀ molecules are produced in the sample. The resulting experimental estimate, 4% for 30 eV incident kinetic energy, fully agrees with our simulation results mentioned above, suggesting the consistency and accuracy of our simulations and experiments.

Comprehensive immunotherapy combined with intratumoral injection of zoledronate-pulsed dendritic cells, intravenous adoptive activated T lymphocyte and gemcitabine in unresectable locally advanced pancreatic carcinoma: a phase I/II trial

Dendritic cell (DC)-based vaccines prepared using various antigen loading methods have been studied for cancer immunotherapy. The in vivo provocation of immunity by the direct injection of DCs without using tumor-specific antigens into tumors after apoptosis-inducing chemotherapy is more applicable. We previously reported that zoledronate-pulsed DCs (Zol-DCs) may induce tumor-antigen-specific CD8+ T cells by activating Vγ9γδT cells. In this report, we studied the feasibility, safety, and efficacy of a comprehensive immunotherapy involving the combined intratumoral injection of Zol-DC, gemcitabine (GEM) and αβT cells in locally advanced pancreatic carcinoma. Seven of 15 patients showed a stable disease (SD) and most of the patients showed long-term clinical responses. The FACT-BRM score was significantly higher in the patients with SD. Additionally the CD8+/Treg ratio significantly increased in SD patients after treatment. The median over-all survival and progression-free-survival of 15 patients were 12.0 months and 5.5 months, respectively. Patients with a pretreatment neutrophil/lymphocyte ratio (NLR) lower than 5.0 showed significantly longer survival. Even in an analysis limited to the patients with an NLR lower than 5.0, the patients whose CD8+/Treg ratio increased more than twofold tended to survive longer. In conclusion, the comprehensive immunotherapy using Zol-DCs, systemic αβT cells, and GEM may synergistically show a therapeutic effect on locally advanced pancreatic carcinoma. By using appropriate and precise biomarkers, such as NLR and CD8+/Treg ratio, the present comprehensive immunotherapy could be more beneficial for patients with pancreatic carcinoma.

Low-dose valproic acid with low-dose gemcitabine augments MHC class I-related chain A/B expression without inducing the release of soluble MHC class I-related chain A/B

To improve natural killer group 2 member D (NKG2D)-dependent cytotoxicity, the inhibition of cleavage and release of major histocompatibility complex class 1-related chain (MIC) molecules from the tumor surface are required. Valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, is able to induce cell-surface MICA/B on tumor cells. In the present study, the ability of VPA and gemcitabine (GEM) to upregulate MICA/B in pancreatic cancer cells was investigated, resulting in the inhibition of cleavage and release of MIC molecules from the tumor surface. Flow cytometry was used to quantify MICA/B expression in six human pancreatic cancer lines. Functional cytotoxic activity of γδT cells against pancreatic cancer cells treated with VPA and GEM was determined using cytotoxicity assays. At low doses of VPA (0.7 mM) and GEM (0.001 µM), which did not induce tumor growth alterations, the agents individually increased cell-surface MICA/B expression in MICA/B-positive cell lines, but not in the MICA/B-negative cell line. Furthermore, the combination of VPA and GEM synergistically induced cell-surface MICA/B expression. In MICA/B-positive cell lines, the increase in MICA/B expression was dependent on VPA concentration. The combination of low-dose VPA and GEM enhanced the susceptibility of the PANC-1 cell line to γδT cell-mediated tumor cell lysis. It was observed that soluble MIC was released from PANC-1 in the culture supernatant following treatment with GEM. However, the combination of low-dose VPA with low-dose GEM increased MICA/B expression without inducing soluble MIC, resulting in enhanced tumor cell lysis. The results of the present study suggest that the combined administration of low-dose VPA with low-dose GEM has the potential to enhance the therapeutic effects of immunotherapy in pancreatic cancer. Furthermore, it is proposed that the combination acts, in part, by upregulating MICA/B and prevents soluble MIC from being released.

Clinical Study on the Medical Value of Combination Therapy Involving Adoptive Immunotherapy and Chemotherapy for Stage IV Colorectal Cancer (COMVI Study)

BACKGROUND

Adoptive immunotherapy for cancer has evolved through development of novel technologies for generating a large number of activated killer cells, such as αβ T-cells, γδ T-cells, and natural killer cells. There has been no prospective trial of combination therapy involving adoptive immunotherapy and first-line chemotherapy for stage IV colorectal cancer. The present pilot study aimed to evaluate the safety and feasibility of combination therapy involving adoptive immunotherapy and chemotherapy for stage IV colorectal cancer (COMVI study).

PATIENTS AND METHODS

The COMVI study was a prospective, single-arm pilot trial. Therapy in each 21-day treatment cycle involved XELOX (130 mg/m² of oxaliplatin on day 1 plus 1,000 mg/m² of capecitabine twice daily on days 1-14), bevacizumab (7.5 mg/kg on day 1), and αβ T-lymphocytes (over 5×10⁹ on day 18) cultured ex vivo with an immobilized antibody to CD3 and interleukin-2.

RESULTS

The study included six patients (two men and four women) between June 2013 and September 2014. The median patient age was 68 years (range=55-75 years). The overall response rate was 83.3% [complete response in two (33.3%); partial response in three (50.0%); stable disease in one (16.7%); no cases of progressive disease]. The tumor volume reduction rate was 53% (range=38.0-100%). The median progression-free and overall survival durations were 567 and 966 days, respectively. Most adverse events were mild-to-moderate in intensity, and no grade 4 adverse events occurred in the six patients. Only one patient experienced grade 3 hypertension and ileus. Immunotherapy-associated toxicity was minimal in this study.

CONCLUSION

Combination therapy involving adoptive immunotherapy and chemotherapy for stage IV colorectal cancer is feasible and safe. Phase II prospective studies are needed to confirm the safety and efficacy of such chemoimmunotherapy.

Efficacy of Adoptive Immune-cell Therapy in Patients with Advanced Gastric Cancer: A Retrospective Study

BACKGROUND

Conventional therapy for advanced gastric cancer (GC) has limited survival benefits. In this retrospective study, we aimed to investigate the efficacy of immune-cell therapy, using in vitro-activated T-lymphocytes with and without dendritic cells (DCs), in combination with standard therapies in terms of the survival of patients with advanced GC.

PATIENTS AND METHODS

A total of 242 patients who were diagnosed as having stage-IV GC were enrolled in this study to receive immune-cell therapy with or without standard therapies, such as chemotherapy, surgery, or radiation therapy. Overall survival was analyzed by the Kaplan-Meier with log-rank test and Cox regression methods.

RESULTS

Immune-cell therapy increased median survival time (21.5 months) in patients with advanced GC. The patients who underwent surgery with or without chemotherapy as a prior treatment showed better prognosis than those who received other therapies (p<0.001). Patients who showed stable disease or a partial response to immune-cell therapy had a better prognosis than those with progressive disease (p<0.001). Multivariate analysis revealed that performance status, the type of immune-cell therapy, and prior treatment were independent prognostic factors for patients with GC. No serious adverse event was reported in immune-cell therapy.

CONCLUSION

Immune-cell therapy might extend the survival of patients with advanced GC.

Hepatectomy for Liver Metastases of Colorectal Cancer After Adoptive Chemoimmunotherapy Using Activated αβ T-cells

BACKGROUND/AIM

Various types of chemoimmunotherapies for malignant tumors have been reported. However, there are few reports on hepatectomy after chemoimmunotherapy. We evaluated the safety and efficacy of hepatectomy for patients with stage IV colorectal liver metastases (CLM) after chemoimmunotherapy using activated αβ T-cells.

PATIENTS AND METHODS

From June 2012 to December 2016, five patients who underwent hepatectomy after receiving capecitabine and oxaliplatin (XELOX) plus bevacizumab and ex vivo-expanded αβ T-lymphocytes as first-line chemoimmunotherapy were included.

RESULTS

The median age of the five patients (two men, three women) was 61.4 (range=56-75) years. The surgical procedure was partial hepatectomy in two, laparoscopic partial hepatectomy in two, and one case of partial hepatectomy with subsegmentectomy. There was no postoperative complication of Clavien-Dindo grade 3A or higher. One patient had multiple lung metastases.

CONCLUSION

Hepatectomy after chemoimmunotherapy using activated αβ T-cells for CLM can be performed safely.

Systemic Intravenous Adoptive Transfer of Autologous Lymphokine-activated αβ T-Cells Improves Temozolomide-induced Lymphopenia in Patients with Glioma

In this clinical study, we investigated the safety and clinical usefulness of systemic adoptive immunotherapy using autologous lymphokine-activated αβ T-cells (αβ T-cells), combined with standard therapies, in patients with malignant brain tumors. Twenty-three patients with different malignant brain tumors, consisting of 14 treated with temozolomide (TMZ group) and 9 treated without temozolomide (non-TMZ group), received systemic intravenous injections of αβ T-cells (mean=10.4 injections/patient for the TMZ group, and 4.78 for the non-TMZ group). No significant adverse effects associated with the αβ T-cell injection were observed, and the total lymphocyte count (TLC) improved significantly in the TMZ group after five injections. Furthermore, CD8-positive or T-cell receptor V gamma -positive cells were increased with TLC in three patients with glioblastoma multiforme. These findings suggest that systemic αβ T-cell immunotherapy is well tolerated, and may help restore an impaired and imbalanced T-cell immune status, and temozolomide- and/or radiotherapy-induced lymphopenia. Future prospective study is needed to clarify the clinical merits of this immunotherapy.

Immunotherapy using activated T cells with chemotherapy for metastatic colorectal cancer

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Background: The programmed death-1 (PD-1), an inhibitory receptor expressed on activated T cells, is demonstrated to induce an immune-mediated response and play a critical role in tumor initiation and development. T cell activation induces effective antitumor immune response in cancer patients. Adoptive immunotherapy of cancer is evolving with the development of novel technologies that generate proliferation of large number of T cells. We evaluated the safety and efficacy of the combination of adoptive immunotherapy using αβ T cells with chemotherapy for metastatic colorectal cancer (mCRC). Methods: Seventeen patients with mCRC received XELOX + bevacizumab + ex vivo expanded αβ T lymphocytes as a first-line chemoimmunotherapy. Results: Median age of the 17 patients (6 men, 11 women) was 64 years (range:38–80). The T cell number was more than 5.0×109 for each infusion. Median progression-free survival was 15.2 months. Response rate was 80% (complete response (CR) = 23.5%, partial response (PR) = 47.1%, stable disease (SD) = 29.4% and progressive disease (PD) = 0%). Most adverse events were mild to moderate in intensity and immunotherapy-associated toxicity was minimal. Conclusions: Combination of adoptive αβ T cell immunotherapy with chemotherapy for mCRC is safe and effective.

[Dendritic cell vaccines loaded with autologous tumor lysates for solid tumors]

Recently, immunotherapy has been utilized as a novel option for the treatment of various malignancies, however, it is necessary to develop immune cell therapy on the basis of the blockade of immune checkpoints, antigen presentation on dendritic cell (DC) vaccines and the high avidity tumor reactive T cells. Autologous tumor lysate-loaded DC vaccines could have a potency to elicit T cells immune response with both epitopes of neoantigen and com- mon antigen; however the innate immunity should be essential for the cross-presentation process. Furthermore, DC vaccines loaded with tumor lysates by electroporation system eli- cited both antigen-specific CD8 and CD4 T cells. In order to break the immunosuppression, the combined therapy of the tumor lysate-loaded DC vaccines and immune checkpoint inhib- itors should be investigated in the future.

Immunological quality and performance of tumor vessel-targeting CAR-T cells prepared by mRNA-EP for clinical research

We previously reported that tumor vessel-redirected T cells, which were genetically engineered with chimeric antigen receptor (CAR) specific for vascular endothelial growth factor receptor 2 (VEGFR2), demonstrated significant antitumor effects in various murine solid tumor models. In the present study, we prepared anti-VEGFR2 CAR-T cells by CAR-coding mRNA electroporation (mRNA-EP) and analyzed their immunological characteristics and functions for use in clinical research. The expression of anti-VEGFR2 CAR on murine and human T cells was detected with approximately 100% efficiency for a few days, after peaking 6-12 hours after mRNA-EP. Triple transfer of murine anti-VEGFR2 CAR-T cells into B16BL6 tumor-bearing mice demonstrated an antitumor effect comparable to that for the single transfer of CAR-T cells engineered with retroviral vector. The mRNA-EP did not cause any damage or defects to human T-cell characteristics, as determined by viability, growth, and phenotypic parameters. Additionally, two kinds of human anti-VEGFR2 CAR-T cells, which expressed different CAR construction, differentiated to effector phase with cytokine secretion and cytotoxic activity in antigen-specific manner. These results indicate that our anti-VEGFR2 CAR-T cells prepared by mRNA-EP have the potential in terms of quality and performance to offer the prospect of safety and efficacy in clinical research as cellular medicine.

Host CD40 Is Essential for DCG Treatment Against Metastatic Lung Cancer

BACKGROUND/AIM

For the application of invariant natural killer T (iNKT) cells in cancer therapy, the CD40-CD40L interaction is indispensable in administering alpha-galactosylceramide (αGalCer). We hypothesized that CD40 plays an important role in dendritic cells (DC) pulsed with αGalCer (DCGs) in the treatment of lung metastases.

MATERIALS AND METHODS

Wild-type (WT) and CD40(-/-) mice were treated with DCGs isolated from WT or CD40(-/-) mice in a B16F10 lung metastases model and NK and NKT cell activity in lungs and the spleen were examined.

RESULTS

DCG treatment improved WT mice survival but CD40(-/-) hosts received no survival benefit. Conversely, attenuation of a therapeutic effect in mice treated with CD40(-/-) DCGs was not observed. The functional activities of NK and NKT cells in DCG-treated CD40(-/-) mice were partially suppressed.

CONCLUSION

Host CD40 is essential for DCG treatment to have a therapeutic effect on B16F10 lung metastases.

Adoptive Chemoimmunotherapy Using Activated αβ T Cells for Stage IV Colorectal Cancer

BACKGROUND/AIM

Adoptive immunotherapy of cancer is evolving with the development of novel technologies that generate proliferation of large numbers of αβ and γδ T cells. We evaluated the safety and efficacy of the combination of adoptive immunotherapy using αβ T cells with chemotherapy for stage IV colorectal cancer (CRC).

PATIENTS AND METHODS

Fifteen patients with advanced or recurrent CRC received XELOX + bevacizumab + ex vivo expanded αβ T lymphocytes as a first-line chemoimmunotherapy.

RESULTS

Median age of the 15 patients (4 men, 11 women) was 65 years (range=49-80). Median progression-free survival was 21.3 months. Response rate was 80% (complete response (CR)=26.7%, partial response (PR)=53.3%, stable disease (SD)=20% and progressive disease (PD)=0%). Most adverse events were mild to moderate regarding their intensity and immunotherapy-associated toxicity was minimal.

CONCLUSION

Combination of adoptive αβ T cell immunotherapy with chemotherapy for stage IV CRC is feasible and safe.

Immunohistochemical Analysis of WT1 Antigen Expression in Various Solid Cancer Cells

For a peptide-pulsed dendritic cell (DC) vaccine to work effectively in cancer treatment, it is significant that the target protein is expressed in cancer cells. Wilms' tumor 1 (WT1) has been identified as a molecular target for immune cell therapy of cancer. We evaluated the protein expression levels of WT1 in various solid tumors, as well as mucin 1 (MUC1) or major histocompatibility complex (MHC) class l molecules. Seven hundred and thirty-eight patients whose tissue samples were examined by immunohistochemical analysis agreed to undergo DC vaccine therapy. The positive staining of WT1 in tumor cells was observed in 25.3% of patients, with only 8.5% of them showing moderate to strong expression; moreover, WT1 tended to localize in the nucleus and cytoplasm. A positive staining of tumor cells by an anti-MHC class l monoclonal antibody was observed in 98.6% and by an anti-MUC1 monoclonal antibody in 76.8% of the patients. In relation to the application of cancer-specific immunotherapy, these findings provide useful information for determining the efficacy of MUC1- and WT1-targeted therapy.

Clinical study on medical value of adoptive immunotherapy with chemotherapy for stage IV colorectal cancer (COMVI study)

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Background: Adoptive immunotherapy of cancer is evolving with the development of novel technologies for generating a large number of activated killer cells such as αβ T cells, γδ T cells, and natural killer (NK) cells. We conducted a pilot study to evaluate the safety and feasibility of the combination treatment of adoptive immunotherapy with chemotherapy for stage IV colorectal cancer. Methods: The COMVI study was a prospective and single-arm pilot trial. Therapy in each 21-day treatment cycle consisted of XELOX (130 mg/m2 of oxaliplatin on day 1 plus 1,000 mg/m2 of capecitabine twice daily on days 1–14), bevacizumab (7.5 mg/kg on day 1) and αβ T lymphocytes (over 5 ×109 on day 18) cultured ex vivo with an immobilized anti-CD3 antibody and interleukin-2. Results: A total of 6 patients were enrolled from June 2013 to September 2014. Baseline characteristics included a median age of 66 years (range: 55-75) for 2 men and 4women. Median PFS was 567 days. Overall response rate was 100 % (CR 33.3%, PR 66.7%, SD 0%, PD 0%). The tumor reduction rate was 53% (38.0–100%). The majority of adverse events were mild to moderate in intensity, and no grade 4 adverse events occurred in the 6 patients. Only one patient experienced grade 3 hypertension and ileus. Immunotherapy-associated toxicity was minimal in this study. Conclusions: The combination treatment of adoptive immunotherapy with chemotherapy for stage IV colorectal cancer is feasible and safe. Phase II prospective studies are warranted to confirm the safety and efficacy of this chemoimmunotherapy. Clinical trial information: UMIN000010908.

Low-dose gemcitabine induces major histocompatibility complex class I-related chain A/B expression and enhances an antitumor innate immune response in pancreatic cancer

We investigated the effect of gemcitabine (GEM), a key drug for pancreatic cancer treatment, on the expression of cell surface MICA/B in pancreatic cancer cells and resulting cytotoxicity of γδ T cells. We assessed the effect of GEM on the upregulation of cell surface MICA/B expression by flow cytometry, utilizing six pancreatic cancer cell lines. MICA and CD16 expressions from resected pancreatic cancer patient specimens, which received neoadjuvant chemotherapy (NAC) with GEM, were analyzed by immunohistochemistry. GEM could increase MICA/B expression on cell surface in pancreatic cancer cell lines (in 2 of 6 cell lines). This effect was most effectively at concentration not affecting cell growth of GEM (0.001 μM), because MICA/B negative population was appeared at concentration at cytostatic and cytotoxic effect to cell growth (0.1 and 10 μM). The cytotoxic activity of γδ T cells against PANC-1 was detected and functions through interactions between NKG2D and MICA/B. However, the enhancement of NKG2D-dependent cytotoxicity with increased MICA/B expression, by GEM treatment, was not observed. In addition, soluble MIC molecules were released from pancreatic cancer cell lines in culture supernatant with GEM treatment. Immunohistochemical staining demonstrated that MICA expression in tumor cells and CD16 positive cells surrounding tumors were significantly higher in the NAC group compared to that of the control group. There was a significant correlation between NAC and MICA expression, as well as NAC and CD16 positive cell expression. The present results indicate that low-dose GEM-induced MICA/B expression enhances innate immune function rather than cytotoxicity in pancreatic cancer. In addition, our result suggests that the inhibition of cleavage and release of MIC molecules from the tumor surface could potentially improve NKG2D-dependent cytotoxicity.

Improvement of Impaired Immunological Status of Patients with Various Types of Advanced Cancers by Autologous Immune Cell Therapy

We evaluated the immunological status of patients with various solid tumors by flow cytometry of immune cell populations and their frequencies in peripheral blood samples. The change in immunological status was also analyzed in patients given autologous immune cell therapy, such as αβT cell, γδT cell, NK cell or DC vaccine therapy. The frequency of regulatory T-cells (Tregs) was shown to be high in patients with cancers of the lung (squamous carcinoma cells), head and neck, esophagus and uterus, although there were no significant differences in effector cell population or Th1/2 ratio between various types of cancers except for a few. The cellular immunological status was impaired in most patients with advanced solid tumors before immune cell therapy and the impaired T-cell immune status was restored by infusion of effector cells, such as αβT cells or γδT cells, although the number of NK cells in the peripheral blood did not always increase after autologous NK cell therapy. The concurrent αβT cell therapy and DC vaccine therapy could successfully increase the number of CD8(+) T-cells in the peripheral blood of patients with various types of cancers. Two or three injections of αβT cells could potentially reduce Tregs frequency prior to DC vaccine, as well as the concurrent αβT cell and DC vaccine therapy. However, an increase in the Tregs frequency was observed in some patients who received NK cell therapy. These findings suggest that it is necessary to include or combine certain types of immune cell therapy when the Tregs frequency of cancer patients is high before or after autologous immune cell therapy.

Abstract 2815: Induction of both OVA specific CD4+ and CD8+ T cells by using PepTivator® OVA-pulsed DCs in mouse model

Antigen specific immune response by both MHC class I-restricted CD8+ T cells and MHC class II-restricted CD4+ T cells is a key event in cancer immunotherapy. In DC vaccine therapy, the short epitope peptides (9 or 10-mer) are mainly used to load, but these short peptides are presented on MHC class I molecule and can stimulate only CD8+ T cells. Using whole protein as antigen might be better to induce both antigen specific CD8+ and CD4+ T cells. The PepTivator® is a peptide pool: consisting mainly of 15-mer sequences with 11 amino acids overlap and covering the complete sequence of target protein. In this study, we used PepTivator® derived from ovalbumin protein (PepTivator® OVA) instead of whole protein as antigen, and evaluated the inducing activity of antigen specific CD8+ and CD4+ T cell responses in mouse model.

In order to examine the antigen presenting ability of PepTivator® OVA-pulsed DCs, CD8+ T cells (106 cells/mL) isolated from OT-I transgenic mouse (OT-I CD8T) or CD4+ T cells (106 cells/mL) isolated from OT-II transgenic mouse (OT-II CD4T) were cultured with PepTivator® OVA-pulsed DCs (5×104 cells/mL) for 4 days. As positive control, OT-I epitope peptide (OVA257-264aa) and OT-II epitope peptide (OVA323-339aa) were used. DCs were prepared from bone marrow cells of C57BL/6 mice after cultivation with medium containing GM-CSF, IL-4 and LPS for 10 days. In preparation of peptide-pulsed DCs, DCs were treated with each peptide at 2 µg/mL for 4 hours and washed with medium to deplete free peptide before use. During the cultivation of OT-I CD8T or OT-II CD4T cells with each peptide-pulsed DCs, the responsive T cell proliferation was measured daily by flow cytometric analysis with absolute count beads and CFSE dye dilution. In addition, cytokines (IL-2 and IFN-gamma) in culture supernatant were measured by ELISA.

As a result, the proliferation of OT-I CD8T cells cocultured with PepTivator® OVA-pulsed DCs seemed to be similar to that in coculture with OT-I epitope peptide-pulsed DCs. In the case of proliferation assay using OT-II CD4T cells, PepTivator® OVA-pulsed DCs showed similar T cell expansion in comparison with OT-II epitope peptide-pulsed DCs. As for cytokines secretion, no difference was observed in concentration of IL-2 and IFN-gamma in both cases using OT-I CD8T and OT-II CD4T cells when PepTivator® OVA was compared with OT-I or OT-II epitope peptide, respectively.

These results showed that PepTivator® OVA pulsed-DCs could induce both antigen specific CD8+ and CD4+ T cell responses in mouse model. It suggests that PepTivator® OVA is at least superior to short epitope peptide in inducing antigen specific T cell response. In addition, it might be big advantage that PepTivator® derived from tumor antigen could be useful in many candidate patients without their HLA restriction. It is expected that therapeutic benefit of PepTivator® pulsed-DCs will be shown in clinical.

Citation Format: Kenji Miki, Koji Nagaoka, Hermann Bohnenkamp, Takayuki Yoshimoto, Takashi Kamigaki, Ryuji Maekawa. Induction of both OVA specific CD4+ and CD8+ T cells by using PepTivator® OVA-pulsed DCs in mouse model. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2815. doi:10.1158/1538-7445.AM2014-2815

Abstract 2539: Clinical prospective study of PepTivator® WT1-pulsed DC vaccines with assessment of immunological responses in solid tumors

Wilms' tumor gene 1 (WT1) is reported to be expressed in various types of malignancies and be one of promising target antigens for cancer immunotherapy. However, the synthetic short peptide vaccines based on the WT1 sequences limit a candidate patient by its HLA restriction. In this study, we performed the clinical study for dendritic cell (DC) vaccines using peptide pools consisting mainly of 15-mer sequences with 11 amino acids overlaps of full-length WT1 protein (PepTivator® WT1). We previously reported that copulsing tumor antigen-pulsed DC with zoledronate (Zol) could efficiently enhance expansion of tumor antigen specific CD8+ T cells by activation of gamma-delta T cells. In the present study, we studied the immunological response induced by PepTivator® WT1-pulsed Zol-DC vaccines in solid tumors, and also investigated the feasibility and safety of PepTivator® WT1-pulsed Zol-DC vaccines.

Five patients with WT1-positive solid tumor (ovary: 4, lung: 1) were enrolled. PBMCs were collected by leukapheresis from the patients and the adherent cell fraction was differentiated into DCs by conventional method. In this vaccine therapy, PepTivator® WT1-pulsed Zol-DC (more than 5x106 cells per injection) was administered to patients subcutaneously for six times every two weeks. In order to examine the specific immune responses to WT1 antigen, PBMCs before therapy (pre-PBMC) and PBMCs after therapy (post-PBMC) were in vitro restimulated with PepTivator® WT1-pulsed Zol-DCs for 14 days and the expanded cells were separated into CD8+ cells and CD4+ cells by MACS, and the antigen specific IFN-gamma- producing cells were detected by ELISpot assay.

As a result, no serious adverse events were seen in three patients who had completed all DC vaccines (Patient ID: #1, #2 and #5). DTH reaction was observed in all three patients. During in vitro restimulation and expansion, there was more than three-fold higher expansion of T cells responding to PepTivator® WT1-pulsed Zol-DC in post-PBMC compared to pre-PBMC among two of three patients (#1, #2). In these two patients, the antigen specific IFN-gamma-producing cells were detected in CD8+ T cells from post-PBMC, but not from pre-PBMC. As for CD4+ T cells, however, the antigen specific IFN-gamma-producing cells were not detected, neither in pre-PBMC, nor in post-PBMC.

We found that PepTivator® WT1-pulsed Zol-DC vaccines are feasible and safe, and can induce antigen specific CD8+ T cells. We need more extensive investigation for the immunological monitoring and clinical outcome.

Citation Format: Shoko Saiwaki, Shigenori Goto, Masashi Takahara, Haruka Matsushita, Takashige Kondo, Hermann Bohnenkamp, Ryuji Maekawa, Takashi Kamigaki. Clinical prospective study of PepTivator® WT1-pulsed DC vaccines with assessment of immunological responses in solid tumors. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2539. doi:10.1158/1538-7445.AM2014-2539

Prospective evaluation of safety of immune-cell therapy for patients with various types of advanced cancer

Several types of immune-cell therapies, such as αβ T-cell, γδ T-cell, and dendritic cell (DC) vaccine therapies, are clinically employed for cancer treatment. The safety of immune-cell therapy for the treatment of patients with malignancies should be maintained by continuous assessment of adverse events. In the present study, we surveyed the adverse events associated with immune-cell therapy using large-scale prospective data and analyzed the side-effect profiles. For the assessment of adverse events associated with immune-cell therapy, we evaluated 771 treatment profiles (484 for αβ T-cell therapy, 58 for γδ T-cell therapy, 206 for DC vaccine therapy, and 23 for concurrent therapy with αβ T-cells and DC vaccines) from 144 patients with various malignancies. For the assessment of fever, fatigue, and itching, each of these adverse events was found to be grade 1 or 2 in most of the treated patients, except for one patient who had grade 3 itching. It was suggested that αβ T-cell therapy could elicit a more rapid and direct immune reaction in patients than DC vaccine therapy, as shown by the earlier development of fever and higher incidence rate of fatigue. It was found that grade 1 or 2 reaction at the injection site developed in 10.2% of the patients injected with DC vaccines. Most of the grade 3 non-hematological and hematological adverse events were associated with disease progression or side-effects of chemotherapy, and were not considered to be related to immune-cell therapy. In conclusion, immune-cell therapy, such as αβ T-cell, γδ T-cell, or DC vaccine therapy, was well-tolerated for cancer treatment.

Allogeneic DCG promote lung NK cell activation and antitumor effect after invariant NKT cell activation

AIM

We aimed to investigate whether allogeneic dendritic cells pulsed with alpha-galactosylceramide (DCG) treatment induces activation of Natural Killer T (NKT) cells.

MATERIALS AND METHODS

C57BL/6 and BALB/c mice were injected with syngeneic and allogeneic DCG. We then examined NK and NKT cell activity in the lung and spleen and antitumor effect in various lung tumor metastatic models.

RESULTS

While splenic NKT activity was suppressed after allogeneic DCG treatment, allogeneic DCG treatment induced similar antitumor effect as well as lung NKT and NK cell activity compared to syngeneic DCG treatment. Furthermore, allogeneic DCG treatment prolonged survival in B16F10, LLC, Pan02, MethA, and CT26 tumor models in two strains of mice.

CONCLUSION

This allogeneic DCG treatment could be substituted for syngeneic DCG treatment. The results obtained in the present study suggest that allogeneic DCG treatment may provide a new approach in cancer immunotherapy with NKT cells.

Zoledronate-pulsed dendritic cell-based anticancer vaccines

The addition of zoledronate to tumor-associated antigen (TAA)-loaded dendritic cells (DCs) promotes the activation of interferon γ-secreting Vγ9 γδ T cells, in turn eliciting TAA-specific CD8⁺ T-cell responses. Immunological responses induced by zoledronate-pulsed DC-based vaccines have been associated with therapeutic effects in clinical trials.

Immunotherapy of autologous tumor lysate-loaded dendritic cell vaccines by a closed-flow electroporation system for solid tumors

Dendritic cell (DC)-based vaccines with the use of various antigen loading methods have been developed for cancer immunotherapy. Electroporation (EP) of a whole tumor cell lysate into DCs was previously found to be more potent for eliciting antigen-specific CD8 + T-cells compared to co-incubation of tumor cell lysates with DCs in vitro. In the present report, we studied the feasibility, safety and antitumor effect in the clinical use of an EP-DC vaccine for the immunotherapy of various types of human solid tumors. We successfully prepared an autologous tumor lysate-loaded EP-DC vaccine with high cell viability by the closed-flow electroporation system. In the phase I clinical trial, mild adverse events associated with the EP-DC vaccine were found during the treatment of advanced or recurrent cancer, or during the adjuvant therapy of some types of cancer; no autoimmune responses were observed after treatment with the autologous tumor lysate-loaded EP-DC vaccines. For the antitumor effect of the EP-DC vaccine against the 41 various types of solid tumor, the overall response rate [complete remission (CR) + partial response (PR)] was 4.9% (2/41) and the clinical benefit rate [CR+ PR + long stable disease (SD)] was 31.7% (13/41). Furthermore, the delayed-type hypersensitivity (DTH) reactivity was positive in most cases of long SD and the positive rate of DTH was 91.7% (11/12) for the patients with clinical benefit. In conclusion, the safety and feasibility of the EP-DC vaccine with autologous tumor lysates were confirmed, and it was found that the antitumor effect might be associated with the immunological response induced by the EP-DC vaccine for cancer immunotherapy.

A patient with scirrhous stomach cancer treated with combination of hyperthermotherapy and 5-aminolevulinic acid (ALA)

A 35-year-old female with scirrhous stomach cancer (stage IV) was treated with a combination of 5-aminolevulinic acid (ALA), sodium dichloroacetate (DCA), hyperthermotherapy, and immunotherapy as terminal care. The patient survived for one year and seven months, during which her quality of life was markedly improved and she returned to work. The patient was diagnosed with poorly-differentiated adenocarcinoma and progressive signet-ring cell carcinoma, accompanied by left ovarian metastasis, peritoneal dissemination, and right hydronephrosis stage IV, and treated with combination chemotherapy with tegafur-gimeracil-oteracil potassium (TS-1) and docetaxel. Oral ALA and DCA were concomitantly administered at 50 mg each three times a day (150 mg/day, respectively). In addition, hyperthermotherapy using thermotron was concomitantly performed at 2- to 3-week intervals. Cellular immunotherapy with αβ T- and immature dendritic cells was also performed. The disease did not progress for 11 months, her quality of life was markedly improved, and she was able to return to work. However, the signs of enlargement of the ovarian metastatic lesion were noted later, for which chemotherapy with four cycles of second-line paclitaxel and a half dose of irinotecan and cisplatin as third-line treatment were performed. Combination of ALA/DCA, hyperthermotherapy, and cellular immunotherapy may be a low-invasive palliative therapy superior in maintaining quality of life of tumor-bearing terminally ill individuals.

Extended survival observed in adoptive activated T lymphocyte immunotherapy for advanced lung cancer: results of a multicenter historical cohort study

Purpose

To clarify the long-term effect of immunotherapy, the effect of adoptive activated T lymphocyte immunotherapy on advanced lung cancer was evaluated in terms of survival time. In addition, the performance status of cancer patients under immunotherapy was examined.

Experimental design

Over 5 × 10⁹ alpha–beta T lymphocytes cultured ex vivo with an immobilized anti-CD3 antibody and interleukin-2 were injected intravenously into patients, once every 2 weeks for 3 months or longer. Follow-up of these patients was carried out using clinical records and by telephone interview questionnaire. Patients undergoing immunotherapy in immunotherapy clinics and those undergoing other anticancer therapies without immunotherapy in seven hospitals in Tokyo were enrolled in this study. Data were analyzed by a third-party statistician. Performance status was studied on another series of various cancer patients who underwent immunotherapy.

Results

The overall median survival time of the patients with the best supportive care, which was obtained using Kaplan–Meier’s model, was 5.6 months, and those with immunotherapy alone, chemotherapy alone, and immuno-chemotherapy were 12.5, 15.7, and 20.8 months, respectively. Using Cox’ proportional hazard model, we examined the possible factors on survival time by univariate analysis. Then, the patients were stratified by gender and histological type for multivariate analysis. Significantly low hazard ratios were observed for immunotherapy and radiotherapy in males with squamous cancer; for chemotherapy and radiotherapy in male with adenocarcinoma; and for immunotherapy in females with adenocarcinoma. Addition of immunotherapy to chemotherapy resulted in a statistically significant decrease in hazard ratio in females with adenocarcinoma. Studies on the performance status (PS), determined according to the European Cooperative Oncology Group criteria, revealed a continuous high level of PS under immunotherapy until around 2 months before death, in contrast to the gradual increase of tumor marker level.

Conclusions

The effectiveness of immunotherapy on advanced lung cancer is limited but may extend life span under certain conditions. Immunotherapy itself provided no clinical benefit by itself as compared with chemotherapy, but a significant additive effect of immunotherapy on chemotherapy was observed in females with adenocarcinoma. Moreover, immunotherapy can maintain good quality of life of the patients until near the time of death.

Rab27a negatively regulates phagocytosis by prolongation of the actin-coating stage around phagosomes

Rab27a, a Rab family small GTPase, is involved in the exocytosis of secretory granules in melanocytes and cytotoxic T-cells. Rab27a mutations cause type 2 Griscelli syndrome, which is characterized by immunodeficiency, including uncontrolled macrophage activation known as hemophagocytic syndrome. However, the role of Rab27a in phagocytosis remains elusive. Here, using macrophage-like differentiated HL-60 cells and C3bi-opsonized zymosan as a pathogen-phagocyte model, we show that Rab27a negatively regulates complement-mediated phagocytic activity in association with F-actin remodeling. We found that transfection of Rab27a shRNA into HL-60 cells enhances complement-mediated phagocytosis. To clarify the mechanisms underlying the elevated phagocytosis in Rab27a knockdown cells, we analyzed the process of phagosome formation focusing on F-actin dynamics: F-actin assembly, followed by F-actin extension around the particles and the subsequent degradation of F-actin, leading to internalization of the particles enclosed in phagosomes. Microscopic analysis revealed that these actin-related processes, including F-actin coating and F-actin degradation, proceed more rapidly in Rab27a knockdown cells than in control HL-60 cells. Both elevated phagocytosis and accelerated F-actin remodeling were restored by expression of rescue-Rab27a and Rab27a-Q78L (GTP-bound form), but not by Rab27a-T23N (GDP-bound form). Furthermore, an increased accumulation of Coronin 1A surrounding F-actin coats was observed in Rab27a knockdown cells, suggesting that the function of Coronin 1A is related to the regulation of the F-actin coating. Our findings demonstrate that Rab27a plays a direct regulatory role in the nascent process of phagocytosis by prolongation of the stage of actin coating via suppression of Coronin 1A. This study may contribute to an explanation of the underlying mechanisms of excessive phagocytosis observed in Griscelli syndrome.

[A case of rectal carcinoid with multiple liver, lymph nodes and bone metastases that responded to an octreotide therapy]

A 45-year-old man was admitted to our hospital with a chief complaint of anal bleeding. Colonoscopy revealed a lower rectal tumor diagnosed as rectal carcinoid on biopsy. Multiple metastatic liver tumors were found on abdominal CT scan. We performed an abdomino-perineal resection, a partial hepatectomy, and TACE. There seemed to be no apparent residues of a carcinoid tumor on abdominal CT. About one year after the first therapy, CT scan had revealed multiple metastases to the liver, lymph nodes and bones. Therefore, we started an octreotide LAR, which remarkably reduced the size of metastatic tumors. The treatment of an octreotide LAR had controlled the progression of metastatic tumors for two and half years. In this case, the effect of an octreotide LAR for recurrence of rectal carcinoid after local therapies brought good controls of symptoms and an inhibition of tumor growth for long-term.

Zoledronate-activated Vγ9γδ T cell-based immunotherapy is feasible and restores the impairment of γδ T cells in patients with solid tumors

Gamma/delta (γδ) T cells play a role in innate immunity and exhibit cytotoxicity toward a large range of tumor types. Recent studies have shown that aminobisphosphonates may be applied to a culture in which a large number of γδ T cells are proliferated ex vivo. We carried out a clinical study of 25 patients with various solid tumors to determine further the safety, immunologic effect and feasibility of zoledronate-activated Vγ9γδ T cell-based immunotherapy. No severe toxicity was observed. In the cells used for the first treatment, the total cell number, frequency and number of CD3(+) Vγ9(+) γδ T cells were 409 ± 284 × 10(7) cells, 56 ± 33% and 255 ± 242 × 10(7) cells, respectively. Aminobisphosphonate therapy or chemotherapy resulted in the suppression of CD3(+) Vγ9(+) γδ T-cell proliferation. The numbers of CD3(+) T cells, CD3(+) Vγ9(+) γδ T cells and CD27(-) CD45RA(-) Vγ9(+) subsets in peripheral blood were significantly lower in patients than in healthy subjects (P < 0.05). From such an impaired immunologic condition, the numbers and frequencies of CD3(+) Vγ9(+) γδ T cells and CD27(-) CD45RA(-) subsets significantly increased in patients treated with this immunotherapy. Zoledronate-activated Vγ9γδ T cell-based immunotherapy that restores the number of Vγ9γδ T cells in cancer patients may provide another mode of adoptive immunotherapy.