Clinical trials of vaccines for immunotherapy in pancreatic cancer

Polyanhydride nanoparticles stabilize pancreatic cancer antigen MUC4β

Pancreatic cancer (PC) is one of the most lethal malignancies and represents an increasing and challenging threat, especially with an aging population. The identification of immunogenic PC-specific upregulated antigens and an enhanced understanding of the immunosuppressive tumor microenvironment have provided opportunities to enable the immune system to recognize cancer cells. Due to its differential upregulation and functional role in PC, the transmembrane mucin MUC4 is an attractive target for immunotherapy. In the current study we characterized the antigen stability, antigenicity and release kinetics of a MUC4β-nanovaccine to guide further optimization and, in vivo evaluation. Amphiphilic polyanhydride copolymers based on 20 mol % 1,8-bis(p-carboxyphenoxy)-3,6-dioxaoctane and 80 mol % 1,6-bis(p-carboxyphenoxy)hexane were used to synthesize nanoparticles. Structurally stable MUC4β protein was released from the particles in a sustained manner and characterized by gel electrophoresis and fluorescence spectroscopy. Modest levels of protein degradation were observed upon release. The released protein was also analyzed by MUC4β-specific monoclonal antibodies using ELISA and showed no significant loss of epitope availability. Further, mice immunized with multiple formulations of combination vaccines containing MUC4β-loaded nanoparticles generated MUC4β-specific antibody responses. These results indicate that polyanhydride nanoparticles are viable MUC4β vaccine carriers, laying the foundation for evaluation of this platform for PC immunotherapy.

Immunological Effects of Histotripsy for Cancer Therapy

Cancer is the second leading cause of death worldwide despite major advancements in diagnosis and therapy over the past century. One of the most debilitating aspects of cancer is the burden brought on by metastatic disease. Therefore, an ideal treatment protocol would address not only debulking larger primary tumors but also circulating tumor cells and distant metastases. To address this need, the use of immune modulating therapies has become a pillar in the oncology armamentarium. A therapeutic option that has recently emerged is the use of focal ablation therapies that can destroy a tumor through various physical or mechanical mechanisms and release a cellular lysate with the potential to stimulate an immune response. Histotripsy is a non-invasive, non-ionizing, non-thermal, ultrasound guided ablation technology that has shown promise over the past decade as a debulking therapy. As histotripsy therapies have developed, the full picture of the accompanying immune response has revealed a wide range of immunogenic mechanisms that include DAMP and anti-tumor mediator release, changes in local cellular immune populations, development of a systemic immune response, and therapeutic synergism with the inclusion of checkpoint inhibitor therapies. These studies also suggest that there is an immune effect from histotripsy therapies across multiple murine tumor types that may be reproducible. Overall, the effects of histotripsy on tumors show a positive effect on immunomodulation.

Role of immune cells in pancreatic cancer from bench to clinical application: An updated review

BACKGROUND

Pancreatic cancer (PC) remains difficult to treat, despite the recent advances in various anticancer therapies. Immuno-inflammatory response is considered to be a major risk factor for the development of PC in addition to a combination of genetic background and environmental factors. Although patients with PC exhibit evidence of systemic immune dysfunction, the PC microenvironment is replete with immune cells.

METHODS

We searched PubMed for all relevant English language articles published up to March 2016. They included clinical trials, experimental studies, observational studies, and reviews. Trials enrolled at Clinical trial.gov were also searched.

RESULTS

PC induces an immunosuppressive microenvironment, and intratumoral activation of immunity in PC is attenuated by inhibitory signals that limit immune effector function. Multiple types of immune responses can promote an immunosuppressive microenvironment; key regulators of the host tumor immune response are dendritic cells, natural killer cells, macrophages, myeloid derived suppressor cells, and T cells. The function of these immune cells in PC is also influenced by chemotherapeutic agents and the components in tumor microenvironment such as pancreatic stellate cells. Immunotherapy of PC employs monoclonal antibodies/effector cells generated in vitro or vaccination to stimulate antitumor response. Immune therapy in PC has failed to improve overall survival; however, combination therapies comprising immune checkpoint inhibitors and vaccines have been attempted to increase the response.

CONCLUSION

A number of studies have begun to elucidate the roles of immune cell subtypes and their capacity to function or dysfunction in the tumor microenvironment of PC. It will not be long before immune therapy for PC becomes a clinical reality.

Does Unintentional Splenic Radiation Predict Outcomes After Pancreatic Cancer Radiation Therapy?

PURPOSE

To determine whether severity of lymphopenia is dependent on radiation dose and fractional volume of spleen irradiated unintentionally during definitive chemoradiation (CRT) in patients with locally advanced pancreatic cancer (LAPC).

METHODS

177 patients with LAPC received induction chemotherapy (mainly gemcitabine-based regimens) followed by CRT (median 50.4 Gy with concurrent capecitabine) from January 2006 to December 2012. Absolute lymphocyte count (ALC) was recorded at baseline, before CRT, and 2 to 10 weeks after CRT. Splenic dose-volume histogram (DVH) parameters were reported as mean splenic dose (MSD) and percentage of splenic volume receiving at least 5- (V5), 10- (V10), 15- (V15), and 20-Gy (V20) dose. Overall survival (OS) was analyzed with use of the Cox model, and development of post-CRT severe lymphopenia (ALC <0.5 K/UL) was assessed by multivariate logistic regression with use of baseline and treatment factors.

RESULTS

The median post-CRT ALC (0.68 K/UL; range, 0.13-2.72) was significantly lower than both baseline ALC (1.42 K/UL; range, 0.34-3.97; P<.0001) and pre-CRT ALC (1.32 K/UL, range 0.36-4.82; P<.0001). Post-CRT ALC <0.5 K/UL was associated with inferior OS on univariate analysis (median, 11.1 vs 15.3 months; P=.01) and multivariate analysis (hazard ratio = 1.66, P=.01). MSD (9.8 vs 6 Gy, P=.03), median V10 (32.6 vs 16%, P=.04), V15 (23.2 vs 9.5%, P=.03), and V20 (15.4 vs 4.6%, P=.02) were significantly higher in patients with severe lymphopenia than in those without. On multivariate analysis, postinduction lymphopenia (P<.001; odds ratio [OR] = 5.25) and MSD (P=.002; OR= 3.42) were independent predictors for the development of severe post-CRT lymphopenia.

CONCLUSION

Severe post-CRT lymphopenia is an independent predictor of poor OS in LAPC patients receiving CRT. Higher splenic doses increase the risk for the development of severe post-CRT lymphopenia. When clinically indicated, assessment of splenic DVHs before the acceptance of treatment plans may minimize the risk of severe post-CRT lymphopenia.

The Association Between Chemoradiation-related Lymphopenia and Clinical Outcomes in Patients With Locally Advanced Pancreatic Adenocarcinoma

OBJECTIVES

Lymphopenia is a common consequence of chemoradiation therapy yet is seldom addressed clinically. This study was conducted to determine if patients with locally advanced pancreatic cancer (LAPC) treated with definitive chemoradiation develop significant lymphopenia and if this affects clinical outcomes.

METHODS

A retrospective analysis of patients with LAPC treated with chemoradiation at a single institution from 1997 to 2011 was performed. Total lymphocyte counts (TLCs) were recorded at baseline and then monthly during and after chemoradiation. The correlation between treatment-induced lymphopenia, established prognostic factors, and overall survival was analyzed using univariate Cox regression analysis. Important factors identified by univariate analysis were selected as covariates to construct a multivariate proportional hazards model for survival.

RESULTS

A total of 101 patients met eligibility criteria. TLCs were normal in 86% before chemoradiation. The mean reduction in TLC per patient was 50.6% (SD, 40.6%) 2 months after starting chemoradiation (P<0.00001), and 46% had TLC<500 cells/mm. Patients with TLC<500 cells/mm 2 months after starting chemoradiation had inferior median survival (8.7 vs. 13.3 mo, P=0.03) and PFS (4.9 vs. 9.0 mo, P=0.15). Multivariate analysis revealed TLC<500 cells/mm to be an independent predictor of inferior survival (HR=2.879, P=0.001) along with baseline serum albumin (HR=3.584, P=0.0002), BUN (HR=1.060, P=0.02), platelet count (HR=1.004, P=0.005), and radiation planning target volume (HR=1.003, P=0.0006).

CONCLUSIONS

Severe treatment-related lymphopenia occurs frequently after chemoradiation for LAPC and is an independent predictor of inferior survival.

Safety and efficacy study of nasopharyngeal cancer stem cell vaccine

In this trial, nasopharyngeal cancer stem cells (CSCs) were separated and cultured to produce a vaccine; its safety and efficacy were prospectively evaluated in low-, medium-, and high-dose groups. Between April and September 2014, we enrolled 90 patients who met the enrolment criteria, and assigned them to three groups (n=30). Throughout the trial, injection site reaction was the most common reaction (81%), and fever was least common (31%); however, there was no difference among the three groups. When the immune responses pre- and post-vaccination were compared, we found that the CSC-specific and -nonspecific response in the medium- and high-dose groups were both significantly enhanced. This study is the first clinical trial of a nasopharyngeal CSC vaccine and preliminarily proves its safety and efficacy.

Adoptive T-cell transfer combined with a single low dose of total body irradiation eradicates breast tumors

The major objectives of tumor vaccination are to induce the regression of established tumors and to favor the establishment of long-lasting tumor-specific immunity, capable of protecting the host from relapse. Immunotherapeutic strategies such as the administration of tumor-associated antigenic peptides offer one means to boost preexisting antitumor CD8⁺ T cell immunity. Our recent work reveals that established breast tumors are rejected and tumor recurrence prevented when low-dose irradiation is combined with the adoptive transfer of Mammaglobin A epitope-specific CD8⁺ T cells.

Combination treatment with comprehensive cryoablation and immunotherapy in metastatic pancreatic cancer

OBJECTIVE

The aim of this study was to retrospectively assess the effect of comprehensive cryosurgery (ablation of intrapancreatic and extrapancreatic tumors) plus immunotherapy in metastatic pancreatic cancer.

METHODS

We divided 106 patients (57 men, 49 women; median age, 65 years) into the cryoimmunotherapy (31 patients), cryotherapy (36 patients), immunotherapy (17 patients), and chemotherapy groups (22 patients). Pretreatment immune function was tested in patients who underwent immunotherapy. Overall survival (OS) after diagnosis of metastatic pancreatic cancer was assessed after a 4-year follow-up.

RESULTS

Median OS was higher in the cryoimmunotherapy (13 months) and cryotherapy groups (7 months) than in the chemotherapy group (3.5 months; both P < 0.001) and was higher in the cryoimmunotherapy group than in the cryotherapy (P < 0.05) and immunotherapy groups (5 months; P < 0.001). In both the cryoimmunotherapy and cryotherapy groups, median OS was higher after multiple cryoablations than after a single cryoablation (P = 0.0048 and 0.041, respectively). In both groups, the median OS was higher in patients with normal immunologic function than in those with immune dysfunction (P < 0.0001 and P = 0.0004, respectively).

CONCLUSIONS

Cryoimmunotherapy significantly increased OS in metastatic pancreatic cancer. Multiple cryoablations and normal pretreatment immunologic function were associated with better prognosis.

Therapeutic outcomes of combining cryotherapy, chemotherapy and DC-CIK immunotherapy in the treatment of metastatic non-small cell lung cancer

Currently there are no effective therapies for the treatment of metastatic non-small cell lung cancer (NSCLC). Here, we conducted a retrospective study of 161 patients to evaluate the therapeutic effects of combining cryosurgery, chemotherapy and dendritic cell-activated cytokine-induced killer cells (DC-CIK) immunotherapy. The overall survival (OS) after diagnosis of metastatic NSCLC to patient death was assessed during a 5-years follow-up period. OS of patients who received comprehensive cryotherapy was (median OS, 20 months; n = 86) significantly longer than that of patients who did not received cryotherapy (median OS, 10 months; n = 75; P < 0.0001). Five treatment combinations were selected: chemotherapy (n = 44); chemo-immunotherapy (n = 31); cryo-chemotherapy (n = 32); cryo-immunotherapy (n = 21); and cryo-chemo-immunotherapy (n = 33). A combination of cryotherapy with either chemotherapy or immunotherapy lead to significantly longer OS (18 months and 17 months, respectively) compared to chemotherapy and chemo-immunotherapy (8.5 months and 12 months, respectively; P < 0.001); however, the median OS of patients who underwent cryo-chemo-immunotherapy was significantly longer (27 months) compared to the other treatment programs (P < 0.001). In conclusion, a combination of cryotherapy, chemotherapy and DC-CIK immunotherapy proved the best treatment option for metastatic NSCLC in this group of patients.

Combination treatment with comprehensive cryoablation and immunotherapy in metastatic hepatocellular cancer

AIM: To retrospectively assess the effect of comprehensive cryosurgery (ablation of intra- and extra-hepatic tumors) plus dendritic cell-cytokine-induced killer cell immunotherapy in metastatic hepatocellular cancer.

METHODS: We divided 45 patients into cryo-immunotherapy (21 patients), cryotherapy (n = 12), immunotherapy (n = 5) and untreated (n = 7) groups. Overall survival (OS) after diagnosis of metastatic hepatocellular cancer was assessed after an 8-year follow-up.

RESULTS: Median OS was higher following cryo-immunotherapy (32 mo) or cryotherapy (17.5 mo; P < 0.05) than in the untreated group (3 mo) and was higher in the cryo-immunotherapy group than in the cryotherapy group (P < 0.05). In the cryo-immunotherapy group, median OS was higher after multiple treatments (36.5 mo) than after a single treatment (21 mo; P < 0.05).

CONCLUSION: Cryotherapy and, especially, cryo-immunotherapy significantly increased OS in metastatic hepatocellular cancer patients. Multiple cryo-immunotherapy was associated with a better prognosis than single cryo-immunotherapy.

Recent progress in canine tumor vaccination: potential applications for human tumor vaccines

Tumor vaccination holds great promise for the treatment of cancer and research concerning tumor vaccination in dogs is of great interest for veterinary as well as human medicine. Indeed, cancer is the leading cause of death in adult dogs and companion animals are acknowledged as excellent preclinical models for human oncology. The license of the veterinary melanoma vaccine (Oncept™) and Provenge® for the treatment of prostate cancer in men established tumor vaccination as a valid treatment modality for cancer. Although the results with this and other vaccines are promising, there are still some hurdles to overcome. In this article, preclinical and clinical trials with tumor vaccines in dogs are discussed, as well as the surplus value of canine cancer patients for human medicine.

Cryotherapy protocols for metastatic breast cancer after failure of radical surgery

To retrospectively assess the effect of cryotherapy in patients with metastatic breast cancer (MBC) but without local recurrence after resection of the primary lesion, we divided 120 MBC patients into cryotherapy (91 patients) and chemotherapy (29 patients) groups. In the cryotherapy group, 37 patients with tumor recurrence received multiple cryoablations, while 54 patients received only a single cryoablation. Moreover, 62 cryotherapy-group patients underwent cryoablation immediately after the detection of metastases (timely cryotherapy); 35 patients received simultaneous immunotherapy (cryo-immunotherapy), and 29 patients underwent cryoablation in our hospital 3 months after receiving chemotherapy in other centers (chemo-cryotherapy and delayed cryotherapy). Overall survival (OS) after the diagnosis of MBC was assessed after a 10-year follow-up. The median OS was higher in the cryotherapy group (55 months) than in the chemotherapy group (27 months; P<0.0001). In the cryotherapy group, longer median OS was associated with multiple (76 months) rather than single cryoablations (48 months; P=0.0005) and with timely (67 months) rather than delayed cryoablation (48 months; P=0.0012). The median OS was higher after cryo-immunotherapy (83 months) than after chemo-cryotherapy (48 months) or cryotherapy alone (43 months; P<0.0001 for both). In conclusion, timely and multiple cryoablations, especially when combined with immunotherapy, offer significant advantages over chemotherapy in extending the OS of MBC patients.