Our study investigated the immunomodulatory effects of sunitinib to rationally design combinational platforms with immunotherapies for the treatment of solid tumors. Using a mouse model, we studied ...the effects of sunitinib given for 4 weeks at concentrations comparable to 37.5–50 mg/day in humans, followed by 2 weeks off the drug (sunitinib 4/2). We assessed the effect of differently timed combinations of sunitinib and a poxvirus‐based vaccine encoding carcinoembryonic antigen (CEA) plus 3 costimulatory molecules on immune responses in CEA‐transgenic (CEA‐Tg) mice. Antitumor studies were performed in CEA‐Tg mice bearing CEA‐transfected MC38 murine colon carcinomas (MC38‐CEA), treated either concurrently or sequentially with sunitinib and vaccine. In vitro, sunitinib inhibited PDGFR phosphorylation on MC38‐CEA cells at concentrations similar to those biologically available during human treatment. In vivo, one cycle of sunitinib 4/2 caused bimodal immune effects: (a) decreased regulatory cells during the 4 weeks of treatment and (b) an immune‐suppression rebound during the 2 weeks of treatment interruption. In a model using CEA‐Tg mice bearing CEA+ tumors, continuous sunitinib followed by vaccine increased intratumoral infiltration of antigen‐specific T lymphocytes, decreased immunosuppressant T regulatory cells and myeloid‐derived suppressor cells, reduced tumor volumes and increased survival. The immunomodulatory activity of continuous sunitinib administration can create a more immune‐permissive environment. In combination with immunotherapies, sunitinib treatment should precede vaccine, to precondition the immune system, to maximize the response to vaccine‐mediated immune enhancement.
Radiofrequency ablation (RFA) is a minimally invasive energy delivery technique increasingly used for focal therapy to eradicate localized disease. RFA-induced tumor-cell necrosis generates an ...immunogenic source of tumor antigens known to induce antitumor immune responses. However, RFA-induced antitumor immunity is insufficient to control metastatic progression. We sought to characterize (a) the role of RFA dose on immunogenic modulation of tumor and generation of immune responses and (b) the potential synergy between vaccine immunotherapy and RFA aimed at local tumor control and decreased systemic progression.
Murine colon carcinoma cells expressing the tumor-associated (TAA) carcinoembryonic antigen (CEA) (MC38-CEA(+)) were studied to examine the effect of sublethal hyperthermia in vitro on the cells' phenotype and sensitivity to CTL-mediated killing. The effect of RFA dose was investigated in vivo impacting (a) the phenotype and growth of MC38-CEA(+) tumors and (b) the induction of tumor-specific immune responses. Finally, the molecular signature was evaluated as well as the potential synergy between RFA and poxviral vaccines expressing CEA and a TRIad of COstimulatory Molecules (CEA/TRICOM).
In vitro, sublethal hyperthermia of MC38-CEA(+) cells (a) increased cell-surface expression of CEA, Fas, and MHC class I molecules and (b) rendered tumor cells more susceptible to CTL-mediated lysis. In vivo, RFA induced (a) immunogenic modulation on the surface of tumor cells and (b) increased T-cell responses to CEA and additional TAAs. Combination therapy with RFA and vaccine in CEA-transgenic mice induced a synergistic increase in CD4(+) T-cell immune responses to CEA and eradicated both primary CEA(+) and distal CEA(-) s.c. tumors. Sequential administration of low-dose and high-dose RFA with vaccine decreased tumor recurrence compared to RFA alone. These studies suggest a potential clinical benefit in combining RFA with vaccine in cancer patients, and augment support for this novel translational paradigm.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Purpose: Poxviral vectors have a proven safety record and can be used to incorporate multiple transgenes. Prior clinical trials with
poxviral vaccines have shown that immunologic tolerance to ...self-antigens can be broken. Carcinoembryonic antigen (CEA) and
MUC-1 are overexpressed in a substantial proportion of common solid carcinomas. The primary end point of this study was vaccine
safety, with immunologic and clinical responses as secondary end points.
Experimental Design: We report here a pilot study of 25 patients treated with a poxviral vaccine regimen consisting of the genes for CEA and MUC-1,
along with a triad of costimulatory molecules (TRICOM; composed of B7.1, intercellular adhesion molecule 1, and lymphocyte
function–associated antigen 3) engineered into vaccinia (PANVAC-V) as a prime vaccination and into fowlpox (PANVAC-F) as a
booster vaccination.
Results: The vaccine was well tolerated. Apart from injection-site reaction, no grade ≥2 toxicity was seen in more than 2% of the
cycles. Immune responses to MUC-1 and/or CEA were seen following vaccination in 9 of 16 patients tested. A patient with clear
cell ovarian cancer and symptomatic ascites had a durable (18-month) clinical response radiographically and biochemically,
and one breast cancer patient had a confirmed decrease of >20% in the size of large liver metastasis.
Conclusions: This vaccine strategy seems to be safe, is associated with both CD8 and CD4 immune responses, and has shown evidence of clinical
activity. Further trials with this agent, either alone or in combination with immunopotentiating and other therapeutic agents,
are warranted.
As hypoxia can mediate resistance to immunotherapy, we investigated the safety, tolerability, and efficacy of combining evofosfamide, a prodrug that alleviates hypoxia, with ipilimumab, an immune ...checkpoint inhibitor, in immunologically "cold" cancers, which are intrinsically insensitive to immunotherapy, as well as in "hot/warm" metastatic cancers that are, atypical of such cancers, resistant to immunotherapy.
In a phase I, 3+3 dose-escalation trial (NCT03098160), evofosfamide (400-640 mg/m
) and ipilimumab (3 mg/kg) were administered in four 3-week cycles. The former was administered on days 1 and 8 of cycles 1-2, while the latter was administered on day 8 of cycles 1-4. Response was assessed using immune-related RECIST and retreatment was allowed, if deemed beneficial, after completion of cycle 4 or at progression.
Twenty-two patients were enrolled, of whom 21 were evaluable, encompassing castration-resistant prostate cancer (
= 11), pancreatic cancer (
= 7), immunotherapy-resistant melanoma (
= 2), and human papillomavirus-negative head and neck cancer (
= 1). Drug-related hematologic toxicities, rash, fever, nausea, vomiting, and elevation of liver enzymes were observed in > 10% of patients. The most common drug-related grade 3 adverse event was alanine aminotransferase elevation (33.3%). Two patients discontinued ipilimumab and 4 required evofosfamide deescalation due to toxicity. Of 18 patients with measurable disease at baseline, 3 (16.7%) achieved partial response and 12 (66.7%) achieved stable disease. The best responses were observed at 560 mg/m
evofosfamide. Preexisting immune gene signatures predicted response to therapy, while hypermetabolic tumors predicted progression. Responders also showed improved peripheral T-cell proliferation and increased intratumoral T-cell infiltration into hypoxia.
No new or unexpected safety signals were observed from combining evofosfamide and ipilimumab, and evidence of therapeutic activity was noted.
A concurrent multicenter, randomized Phase II trial employing a recombinant poxviral vaccine provided evidence of enhanced median overall survival (OS) (p = 0.0061) in patients with metastatic ...castrate-resistant prostate cancer (mCRPC). The study reported here employed the identical vaccine in mCRPC to investigate the influence of GM-CSF with vaccine, and the influence of immunologic and prognostic factors on median OS. Thirty-two patients were vaccinated once with recombinant vaccinia containing the transgenes for prostate-specific antigen (PSA) and three costimulatory molecules. Patients received boosters with recombinant fowlpox containing the same four transgenes. Twelve of 32 patients showed declines in serum PSA post-vaccination and 2/12 showed decreases in index lesions. Median OS was 26.6 months (predicted median OS by the Halabi nomogram was 17.4 months). Patients with greater PSA-specific T-cell responses showed a trend (p = 0.055) toward enhanced survival. There was no difference in T-cell responses or survival in cohorts of patients receiving GM-CSF versus no GM-CSF. Patients with a Halabi predicted survival of <18 months (median predicted 12.3 months) had an actual median OS of 14.6 months, while those with a Halabi predicted survival of ≥18 months (median predicted survival 20.9 months) will meet or exceed 37.3 months, with 12/15 patients living longer than predicted (p = 0.035). Treg suppressive function was shown to decrease following vaccine in patients surviving longer than predicted, and increase in patients surviving less than predicted. This hypothesis-generating study provides evidence that patients with more indolent mCRPC (Halabi predicted survival ≥18 months) may best benefit from vaccine therapy.
The ultimate goal of therapeutic vaccines is to activate and exploit the patient's own immune system to vigorously and dynamically seek and eradicate established malignant or virally infected cells. ...Therapeutic vaccines also offer the potential for preventing disease recurrence. Saccharomyces cerevisiae‐based vaccines, where the yeast is engineered to express viral or tumor antigens, represent an ideal therapeutic approach due to their ability to stimulate tumor‐ or viral‐specific CD4⁺ and CD8⁺ T‐cell responses that are capable of reducing disease burden. This review describes preclinical and clinical studies supporting the development of S. cerevisiae‐based therapeutic vaccines for the treatment of cancer and viral diseases, as well as multimodal strategies in which therapeutic vaccines are combined with cytotoxic drugs to achieve a greater clinical response.
The goal of vaccine-based cancer immunotherapy is to induce a tumor-specific immune
response that ultimately reduces tumor burden. However, the immune system is often
tolerant to antigens presented ...by the tumor, as the cancer originates from within a patient
and is therefore recognized as self. This article reviews selected clinical strategies for
overcoming this immune tolerance, and approaches to enhance generation of immunity to
tumor-associated antigens by activating innate immunity, potentiating adaptive immunity,
reducing immunosuppression, and enhancing tumor immunogenicity. Success in the field
of cancer vaccines has yet to be fully realized, but intelligent choice of
immunomodulators, tumor antigens, and patient populations will likely lead to clinically
relevant uses for cancer vaccines.
The 5-year survival rate for stage IB-III non-small-cell lung cancer (NSCLC) remains 15%. Surgical resection followed by adjuvant chemotherapy with cisplatin and vinorelbine is one standard-of-care. ...We sought to determine in a preclinical model whether (a) the combination of cisplatin and vinorelbine could positively modulate components of the immune system independent of antitumor activity, and (b) there were synergistic effects of this drug combination and vaccine immunotherapy. We examined the effect of cisplatin/vinorelbine on gene expression, cell-surface phenotype, and CTL-mediated cytolysis of murine lung carcinoma cells in vitro; we also assessed the effects of cisplatin/vinorelbine on immune subsets and function of Tregs in vivo. Finally, we evaluated the potential synergy between chemotherapy and a recombinant yeast-CEA vaccine in a murine model transgenic for CEA with mice bearing lung tumors. These studies demonstrate that exposure of lung tumor cells to the platinum doublet cisplatin/vinorelbine modulates tumor cell phenotype and increases sensitivity to CTL-mediated cytolysis. These studies also demonstrate that cisplatin/vinorelbine (a) induces sub-myeloablative leucopenia that differentially modulates reconstitution of Treg versus effector T-cell subsets and (b) can be employed synergistically with vaccine, exploiting homeostatic peripheral expansion of T cells. Antitumor studies show for the first time that cisplatin/vinorelbine combined with vaccine increases the survival of mice with established NSCLC. These findings provide the rationale for the potential clinical benefit of the combined use of vaccine with cisplatin/vinorelbine chemotherapy regimens.
Abstract
Molecular Templates is developing engineered toxin bodies (ETBs), potent recombinant immunotoxins that combine the specificity of an antibody fragment with the powerful direct cytotoxicity ...of the Shiga-like toxin A subunit to specifically kill target expressing cells. Once delivered to appropriate cells, the Shiga toxin A subunit inhibits protein synthesis and promotes apoptosis of tumor cells. Bacterial or plant derived toxin moieties have the potential to induce an immune response, commonly limiting repeat dosing of immunotoxins. Our next-generation ETB scaffold has been modified to overcome this limitation through genetic engineering to systematically and comprehensively reduce B and CD4+T cell epitopes.
Molecular Templates has developed a proprietary epitope class switching technology designed to both reduce the anti-drug response and promote the anti-tumor response by replacing naturally occurring CD4+ T cell epitopes with CD8+ T cell epitopes. We have found that a combination of surface remodeling and epitope class switching combined in one protein results in powerful reductions in the anti-drug response against ETBs after repeat administration. This de-immunized next-generation scaffold retains the potency and specificity of the unmodified ETB. Additionally, the engineering of CD8+ T cell epitopes on the ETB scaffold can allow for foreign antigen presentation in complex with MHC class I on the tumor cell surface. This antigen presentation may recruit activated cytotoxic T lymphocytes (CTLs) to the tumor microenvironment thereby adding an additional mechanism of action to the direct cell kill activity of the ETBs.
The second generation ETB scaffold has been combined with multiple target binding domains, including scFvs that target CD38, PD-L1 and HER2. CD38 is a validated target for multiple myeloma, and our CD38 targeted ETB has shown potent activity in vitro and in vivo. Pre-clinical studies have shown effective combination of the CD38 targeted ETB with standard of care agents such as IMiDs. Additionally, we have developed a PD-L1 targeted ETB that can be used against various PD-L1 expressing malignancies including Hodgkin's lymphoma and melanoma. HER2 is a well characterized target in breast cancer that persists in many patients after HER2 targeted treatment relapse; a novel MOA to this target may impart additional clinical benefit. The potency, reduced immunogenicity, unique mechanism of action and immune modulating activities of ETBs in this second generation scaffold allows for these agents to fit in well in a refractory setting as well as in combination with other agents in the growing field of immuno-oncology.
Citation Format: Sangeetha Rajagopalan, Garrett L. Robinson, Brigitte Brieschke, Jennifer Erdman, Jane Neill, Jack P. Higgins, Erin K. Willert. Next-generation engineered toxin bodies: CD38, PD-L1 and HER2 targeted ETBs. abstract. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 595.
Small molecule BCL‐2 inhibitors are being examined as monotherapy in phase I/II clinical trials for several types of tumors. However, few data are available about the effect of BCL‐2 inhibitors on ...immune function. The aims of our study were to investigate the effect of a small molecule BCL‐2 inhibitor on immune function and determine the most effective way of combining this inhibitor with a recombinant vaccine to treat tumors. The in vitro effect of the pan‐BCL‐2 inhibitor GX15‐070 was assessed in mouse CD8 T lymphocytes at 2 different stages of activation as well as regulatory T lymphocytes (Treg). The in vivo effect of GX15‐070 after recombinant vaccinia/fowlpox CEA‐TRICOM vaccination was analyzed in tumor‐infiltrating lymphocytes, and in splenocytes of mice bearing subcutaneous tumors. The therapeutic efficacy of such sequential therapy was measured as a reduction of pulmonary tumor nodules. Activated mature CD8 T lymphocytes were more resistant to GX15‐070 as compared to early‐activated cells. Treg function was significantly decreased after treatment with the BCL‐2 inhibitor. In vivo, GX15‐070 was given after vaccination so as to not negatively impact the induction of vaccine‐mediated immunity, resulting in increased intratumoral activated CD8:Treg ratio and significant reduction of pulmonary tumor nodules. Our study is the first to show the effect of a small molecule BCL‐2 inhibitor on the immune system and following a vaccine. It is also the first to demonstrate the efficacy of this sequence in reducing tumors in mouse models, providing a rationale for the design of combinational clinical studies.
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