Administration Of Low-dose Cyclophosphamide Research Articles

Antitumor activity of mHSP65-TTL enhanced by administration of low dose cyclophosphamide in pancreatic cancer-bearing mice

Pancreatic cancer remains a lethal malignancy. Despite chemotherapy or/and radiotherapy after the surgery, the improvement on the overall survival of the patients has still been minimal. To develop novel therapeutic approaches, we tried to prepare mHSP65-TTL, a candidate vaccine prepared by mixing the recombinant mycobacterial heat shock protein 65 (mHSP65) with tumor tissue lysate (TTL) of Panc02 pancreatic cancer tissue. The mHSP65-TTL were used to immune the C57BL/6 mice implanted with the Panc02 cancer cells, in combination with or without low dose cyclophosphamide (CY). The results showed that mHSP65-TTL significantly prolonged the survival of the pancreatic cancer bearing mice and low dose CY enhanced the efficacy of the mHSP65-TTL. In addition, we detected mRNA expression of RORγt and IL-17A in spleen cells of mice received mHSP65-TTL or mHSP65-TTL plus CY, and found that mHSP65-TTL up-regulated mRNA expressions of RORγt and IL-17A, CY alone or mHSP65-TTL plus CY up-regulated mRNA expressions of RORγt. The work could provide an insight into a combinational approach for the immunotherapy of pancreatic cancer.

Abstract 12529: Low Dose Oral Cyclophosphamide Therapy Reduces Atherosclerosis Progression and Promotes Plaque Stability in a Murine Model of Atherosclerosis

Introduction: Atherosclerosis is a chronic inflammatory disease and the primary cause of heart disease and stroke in Western countries. The cytotoxic drug cyclophosphamide (CPA) can modulate immune functions. Extended survival of patients with severe atherosclerosis has been reported after CPA treatment, but the underlying mechanism is still poorly understood. The objective of this study was to examine the antiatherosclerotic effects of CPA and the underlying mechanism in a murine model of atherosclerosis. Hypothesis: CPA treatment can alter inflammatory processes pivotal for the development of atherosclerosis, therefore limiting disease progression. Method: Apolipoprotein E deficient (ApoE-/-) mice fed a high fat diet received CPA resuspended in drinking water (37.5 g/kg /day p.o.) or water for 12 weeks, respectively. In an interventional protocol, mice fed a high fat diet received the same dose of CPA or water from week 14 to 18, respectively. Mice were sacrificed at week 12, 14 and 18, and aorta, peripheral blood cells, spleen cells and peritoneal cells of treated mice were analysed using histological methods and FACS analysis. Result: In a preventive protocol, continuous oral administration of low-dose CPA prevented disease initiation in ApoE-/- mice fed with a high fat diet. Encouraged by these data we treated mice with pre-established atherosclerosis for 4 weeks with CPA, in an interventional protocol. CPA treatment delayed disease progression in mice with advanced atherosclerosis and reduced the macrophage infiltration in plaques. Importantly, improved plaque stability with a thicker fibrous cap, and an increase in collagen deposition and decreased matrix metalloproteinase-2 and -9 expression, and a reduction of classical inflammatory macrophage (M1) numbers was observed. In addition, CPA treatment reduced the numbers of IFN-γ-producing TH1, but not TH2 lymphocytes in vivo. Conclution: Our data demonstrate that oral treatment with CPA inhibits atherosclerosis initiation and progression in ApoE-/- mouse model, through pleiotropic immunomodulatory effects on lymphoid and myeloid cells. Thus, CPA may be a valuable drug for treating advanced atherosclerosis.

IS5-1 - Immune and Gene Therapy as an Emerging Cancer Treatment

Although there have been much progress in cancer treatment, there still are many patients who suffered from advanced or metastatic cancers which are refractory to current standard anticancer treatments. We have been involved in two new approaches, namely immunotherapy at clinical level and oncolytic virotherapy at preclinical level, to develop new therapy targeting such disastrous condition. Our first approach is the immunotherapy. We have recently concluded the Phase I clinical trial of multiplex vaccinations with HLA-A*2402 restricted tumor-associated antigens peptides (TAA), preceded by the administration of low-dose cyclophosphamide (CPM) in order to eliminate Tregs and confirmed the safety and efficacy of this new immune therapy. Furthermore, we have been conducting a Phase I clinical trial of immune cell therapy in order to confirm the safety and efficacy of CTL, in solid tumor patients preconditioned by CPM and followed by the dendritic cells and interleukin-2. This study targeted the novel HLA-A*0201 or HLA-A*2402-restricted TAA, RING finger protein 43, and was designed to administrate CTL at two dose levels. Both of our two clinical trials so far showed no severe adverse events, greater than Grade 3, in our patients. Clinical responses of stable disease (SD) and mixed response were observed. In conclusion, these trials are tolerable and may be clinically efficient for patients suffered from advanced solid tumor. Further immunological assessment should be conducted to explore the valid biomarkers in order to predict clinical efficacy before treatment. Our second approach is the oncolytic virotherapy. We previously demonstrated that intratumoral injection of coxsackievirus B3 (CVB3) induced not only a potent oncolytic activity followed by systemic antitumor immune stimulation, but also myocarditis and pancreatitis in syngeneic non-small cell lung cancer (NSCLC) -loaded mice. To improve the safety profile of CVB3, we successfully constructed a novel recombinant CVB3 by inserting two normal tissue-specific microRNA target sequences complementary to miR-1 and miR-217 into the CVB3 genome (CVB3-miRT) . CVB3-miRT showed more abundant viral replication than the parental CVB3 in NSCLC cells with low expression levels of miR-1 and miR-217. On the other hand, both of miR1-transduced NSCLC cells as well as normal lung fibroblast cells were dramatically resistant to the oncolysis by CVB3-miRT infection. Of note, serial administrations of CVB3-miRT, but not parental CVB3, into human NSCLC xenograft tumors in nude mice, elicited attenuated histological findings of both pancreatitis and myocarditis without weight loss, and decreased serum amylase level without losing its original significant antitumor activity. Collectively, our novel genetically attenuated strain of CVB3 could be a promising antitumor modality for the treatment of NSCLC patients. In this symposium, our recent data on these two new approaches will be presented.

Abstract LB-172: A phase I clinical trial of RNF43 peptide-specific immune cell therapy combined with low-dose cyclophosphamide for patients with advanced solid tumors

Abstract Accumulated clinical studies have validated the efficacy of immunotherapies for patients with solid tumors. Although effective anti-tumor immune responses have been introduced in many clinical trial cases, several immunosuppressive factors such as regulatory T cells (Tregs) have been considered to inhibit induction of anti-tumor immunity. We have developed new approach of immunotherapy in order to augment anti-tumor effect by expanding tumor-specific cytotoxic T cells (CTL), and eliminate Tregs by utilizing chemotherapy. We have recently reported the efficacy of multiplex vaccination with HLA-A*2402 restricted tumor-associated antigens peptides (TAA), preceded by the administration of low-dose cyclophosphamide (CPM) in order to eliminate Tregs. This time, we have been conducting a phase I clinical trial to study the utilization of CTL after CPM administration followed by a consequent administration of dendritic cells (DC) and IL-2. This study targets the novel HLA-A*0201 or HLA-A*2402-restricted TAA, RING finger protein 43 (RNF43), and is designed as a dose-escalation study of CTL. The purpose of this trial is to evaluate the safety and tolerability of the proposed method as primary endpoint and the efficacy including over all survival and immune responses as secondary endpoint. 11 patients with advanced solid tumors refractory to standard therapy were enrolled in this trial. They were HLA-A*2402 or A*0201 positive and exhibiting RNF43 expression levels in their tumor cells more than those in RNF43-positive control cell (HCT15). Primarily, severe adverse event greater than Grade 3 was not observed in our patients. Clinical responses of stable disease (SD) were observed in 8 out of 11 patients. Among them, 2 patients showed a decrease in the tumor markers with stabilized tumor sizes during the observed period, and 1 patient showed a mixed response. On the other hand, 3 other patients showed progressive disease (PD). The number of Tregs significantly decreased after the administration of CPM (p=0.033), and the higher decreasing rate of Tregs was related to the good clinical response. In CD107a/b mobilization assay, the ratio of RNF43-specific CD8 T cells in SD increased with time, conversely that in PD decreased (p=0.005). Also, in Intracellular Staining Assay, the ratio of IFN-g produced by RNF43-specific CD8 T cells was significantly correlated with clinical benefit (p=0.02), while TNF-α and IL-2 were not. Consequently, the combination of immunotherapy and CPM may induce tumor specific immune cells accompanied by the decreased number of Tregs. In conclusion, this trial is tolerable and may be clinically efficient against advanced solid tumors. Further immunological assessment should be conducted in order to explore the valid biomarkers to predict clinical efficacy before treatment. Citation Format: Yasuki Hijikata, Toshihiko Okazaki, Hiroyuki Inoue, Yoshihiro Tanaka, Kenzaburo Tani, Shinichi Kobayashi, koji Yoshida. A phase I clinical trial of RNF43 peptide-specific immune cell therapy combined with low-dose cyclophosphamide for patients with advanced 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 LB-172. doi:10.1158/1538-7445.AM2014-LB-172

Evaluation of cyclophosphamide as an immune enhancer for the NY-ESO-1/ISCOMATRIX vaccine in patients with metastatic melanoma.

3093^ Background: We have previously demonstrated potent immunogenicity of the NY-ESO-1/ISCOMATRIX vaccine in patients with resected melanoma; however the same vaccine induced only a few vaccine antigen specific immune responses in patients with advanced disease. Therefore, we have enrolled a second cohort of patients with advanced melanoma in the clinical trial LUD2002-013 to investigate whether pre-treatment with the immune-modulator cyclophosphamide could improve the immunogenicity of the NY-ESO-1/ISCOMATRIX vaccine. Methods: LUD2002-013 was an open-label phase II study intended to evaluate the safety and immunogenicity of the NY-ESO-1/ISCOMATRIX vaccine in patients with advanced melanoma. The first cohort of patients received vaccine alone; a second cohort with 19 patients was added after evaluation of responses in Cohort 1 and received vaccine in combination with low-dose cyclophosphamide. Patients received 3 injections of NY-ESO-1 ISCOMATRIX preceded, in Cohort 2, by cyclophosphamide at a dose of 300 mg/m2 every four weeks. Assessment of clinical and immunological responses was undertaken at week 11. Results: Fifteen patients of Cohort 2 completed at least one cycle of vaccination. No objective responses were observed with three patients having stable disease for more than three months. The inclusion of cyclophosphamide into the vaccination protocol did not lead to any significant toxicity. Seven of fourteen patients in Cohort 2 developed a vaccine induced NY-ESO-1 specific CD4 T cell response, a significant increase compared to cohort 1 (p=0.019). No differences were observed in the frequency of vaccine induced antibody or CD8 T cell responses. No change in the frequency of peripheral blood regulatory T cells or myeloid derived suppressor cells was detected. Conclusions: The administration of low dose cyclophosphamide has significantly increased the NY-ESO-1 specific CD4 T cell response of the NY-ESO-1/ISCOMATRIX vaccine in patients with metastatic melanoma. Given the emerging importance of CD4 T cells in tumour regression, the present findings warrant further clinical exploration of combining cyclophosphamide with vaccines and other immune-modulatory agents. Clinical trial information: NCT00518206.

Abstract 5605: Targeting cancer stem cells in squamous cell carcinoma of the head and neck with combinatorial adoptive immunotherapy

Abstract According to current views, in order for cancer immunotherapy to be successful it must target cancer stem cells (CSC) and counteract the multiple mechanisms involved in immune escape. Guided by these concepts, we have developed a combinatorial adoptive immunotherapeutic strategy which utilizes a monoclonal antibody (mAb) and cytotoxic T lymphocytes (CTL) in combination with continuous administration of low dose cyclophosphamide (metronomic chemotherapy) to target CSC and differentiated tumor cells, as well as activated pericytes in the tumor microenvironment. The targets selected are aldehyde dehydrogenase 1 family member A1 (ALDH1A1) and chondroitin sulfate proteoglycan 4 (CSPG4). We now report that ALDHbright cells in squamous cell carcinoma of the head and neck (SCCHN) cell lines, which express high levels of ALDH1A1, are tumorigenic at low inoculum in immunodeficient mice, and particularly sensitive to recognition by ALDH1A1-specific T cells. The ALDHbright cells express CSPG4, a cell surface antigen functional in adhesion and migration. CSPG4 is also expressed on tumor associated activated pericytes which stabilize tumor blood vessels and provide vascular endothelial cells with survival signals. Administration of CSPG4-specific mAb and metronomic chemotherapy combined with intralesional adoptive transfer of ALDH1A1 peptide-specific CTL to mice bearing human SCCHN PCI-13-derived xenografts significantly reduced tumor growth and number of tumor cells with CSC phenotype. The antitumor effects of the immunotherapy we have developed were significantly higher than those of its individual components. These results argue in favor of the possibility that this combinatorial strategy may enhance the clinical efficacy of adoptive immunotherapy in SCCHN patients. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5605.

Immunological and clinical effects of a multiple peptide vaccine and low-dose cyclophosphamide in prostate carcinoma patients

13502 Background: Despite effective therapeutic strategies for the treatment of prostate cancer (PC), patients still recur and progress in a significant percentage. Here we describe the preliminary clinical and immunological data of a peptide-based strategy of vaccination in biochemical relapsed PC patients. Methods: We planned to enroll 30 HLA-A*0201 patients with biochemical failure after surgery, radiation or androgen deprivation therapy (ADT), according to the ASTRO criteria. On entering the study, patients discontinue ADT. No selections were made based on PSA levels at diagnosis, Gleason pattern score or other pathological features. Vaccination includes three peptides derived from proteins highly expressed in PC, PSMA (PSMA-P14–12 and PSMA-P2711–719) and Survivin (SVV96- 104/97M). Peptides, emulsified in Montanide ISA 51, are administered subcutaneously (8 injections) at two-weeks intervals. Vaccine is preceded by systemic administration of low dose cyclophosphamide (300 mg/m2/four weeks), aimed at selectively down- modulating regulatory T cells (Treg). Immunological monitoring includes evaluation of peptide and tumor-specific CD8+T cells in peripheral blood (IFN?-Elispot and HLA/multimer staining) and analysis of the frequency and suppressive activity of CD4+CD25+Foxp3+Treg. Results: So far, ten patients have been enrolled. Treatment is well tolerated, with mild cutaneous toxicity due to Montanide injection. A significant increase in the frequency of antigen-specific CD8+ T cells was observed in 8/10 patients. Treg, only marginally expanded in these patients, do not seem to decrease by cyclophosphamide treatment, although studies on the potential modulation of their suppressive activity are in progress. After a follow-up of 6–12 months, PSA stabilization was observed in 7 patients, 2 of which entered the trial after maximal androgen blockade discontinuation. Interestingly, PSA stabilization appears to directly correlate with the induction of antigen-specific T cell responses. Conclusions: Our vaccination strategy proved to be safe, non toxic and well tolerated. Initial monitoring data show an expansion of antigen specific T cells, with an apparent correlation between immunological and biochemical responses. No significant financial relationships to disclose.

Single administration of low dose cyclophosphamide augments the antitumor effect of dendritic cell vaccine.

Single administration of low dose cyclophosphamide (CTX) was previously reported to enhance the antitumor efficacy of immunotherapies. To investigate the possible mechanisms for this effect, we examined whether a single administration of low dose CTX could augment the immunogenicity of dendritic cell (DC) vaccines. Fifty milligrams per kilogram body weight dose of CTX was administrated intraperitoneally to mice after B16 melanoma or C26 colon carcinoma tumor models were established, DC vaccine generated from mouse bone marrow and pulsed with B16 or C26 tumor cells lysates were vaccinated 4 days later. CTX treatment potentiated the antitumor effects of the DC vaccine, and increased the proportion of IFN-gamma secreting lymphocytes in spleens. Furthermore, a significantly reduced proportion of CD4+CD25+FoxP3+ regulatory T (Treg) cells was detected by flow cytometry in spleen lymphocytes from tumor-bearing mice treated with CTX. Thus, a single administration of low dose CTX could augment antitumor immune responses of DC vaccine by reducing the proportion of CD4+CD25+FoxP3+ Treg cells in tumor-bearing mice. Our results suggested a possible mechanism of CTX-induced immunopotentiation and provided a strategy of immunotherapy combining a low dose CTX with DC vaccine.

Different mechanisms for anti-tumor effects of low- and high-dose cyclophosphamide

It is known that, besides its direct cytotoxic effect as an alkylating chemotherapeutic agent, cyclophosphamide also has immuno-modulatory effects, such as depletion of CD4+CD25+ regulatory T cells. However, its optimal concentration has not yet been fully elucidated. Therefore, we first compared the effects of different doses of cyclophosphamide on T cell subsets including CD4+CD25+ T cells in mice. Cyclophosphamide (20 mg/kg) decreased the numbers of splenocytes, CD4+ and CD8+ T cells by approximately 50%, while a decline in CD4+CD25+ T cell number was more profound, leading to the remarkably lower ratios of CD4+CD25+ T cells to CD4+ T cells. In contrast, 200 mg/kg cyclophosphamide severely decreased the numbers of all the T cell subsets by > 90% although the decreased ratios of CD4+CD25+ T cells to CD4+ T cells were still observed. Next, low-dose cyclophosphamide significantly inhibited in vivo growth of murine hepatoma MH129 tumor in immuno-competent but not immuno-deficient mice. This anti-tumor effect was abolished by CD4+CD25+ T cell repletion. In contrast, high-dose cyclophosphamide exhibited similar anti-tumor effects in both mice. In addition, contrary to antibody-mediated CD4+CD25+ T cell depletion, administration of low-dose cyclophosphamide after tumor inoculation was more efficacious than the prior administration. Our data show that low-dose cyclophosphamide selectively depletes CD4+CD25+ T cells, leading to enhanced anti-tumor effects against pre-existing tumors, while the anti-tumor effect of high-dose cyclophosphamide is solely attributed to its direct cytotoxicity. These findings appear to be highly crucial in a clinical setting of combined chemotherapy and immunotherapy for cancer treatment.

Prolongation of allograft survival by repeated cycles of donor antigen and cyclosporine in rat kidney transplantation.

Combination therapy with a short course of cyclosporine (CsA) on the day prior to, to day of, and the day after transplantation and one dose of 5 mg 3M-KCl-extracted donor-soluble antigen (Ag) prolongs the survival of Buffalo (Buf, RT1b) kidney allografts in Wistar-Furth (WFu, RTu) inbred rats because of the induction of specific suppressor cells. Four systems were utilized to demonstrate suppressor cell activity in vivo. First, pooled lymphocytes from CsA-Ag-treated hosts suppressed the capacity of admixed, syngeneic WFu cells to display an in vivo mixed lymphocyte culture reaction toward donor Buf, but not third-party Brown-Norway (BN, RT1n), hosts. Second, systemic adoptive transfer two days prior to, or on the day of, transplantation of 5 x 10(8) putative suppressor cells harvested ten days after combined Ag-CsA treatment prolonged graft survival slightly but significantly from 7 to 9 days in virgin, secondary hosts. Third, admixture of 5 x 10(8) cells from Ag-CsA-treated hosts vitiated the capacity of 5 x 10(8) virgin WFu spleen cells to restore the capacity of recipients sublethally irradiated with 500 rads to reject. Buf allografts at 7.9 days rather than 16.7 days. Fourth, i.p. administration of low-dose cyclosphophamide (CY) 7 days after transplantation, a regimen known to inhibit suppressor cells, reduced the capacity of the Ag-CsA regimen to prolong graft survival. Two additional cycles of CsA therapy at 10-day intervals administered in an attempt to maintain T suppressor dominance over T helper cells prolonged median graft survival to 65 days. Similar prolongation was not achieved using donor blood transfusion as the immunogen, or using cycles of CsA alone. These findings suggest that 3M KCl donor antigen amplifies the induction of specific suppressor cells, and that CsA by virtue of helper T cell inhibition facilitates the establishment of suppressor cell dominance, eventually leading to host unresponsiveness.