The impact of immunosuppressive agents on immune checkpoint inhibitor efficacy in patients with advanced melanoma: A real-world, multicenter, retrospective study.

BACKGROUND: Immune-related adverse events (irAEs) associated with immune checkpoint inhibitors (ICIs) are often managed via immunosuppressive agents (ISAs); however, their impact on ICI efficacy is not well studied. The impact of the use of ISAs on ICI efficacy in patients with advanced melanoma was therefore investigated. METHODS: This is a real-world, multicenter, retrospective cohort study of patients with advanced melanoma who received ICIs (n = 370). Overall survival (OS) and time to treatment failure (TTF) from the time of ICI initiation were compared among patients in subgroups of interest by unadjusted and 12-week landmark sensitivity-adjusted analyses. The association of irAEs and their management with OS and TTF were evaluated using univariate and multivariable Cox proportional hazards regression models. RESULTS: Overall, irAEs of any grade and of grade ≥3 occurred in 57% and 23% of patients, respectively. Thirty-seven percent of patients received steroids, and 3% received other ISAs. Median OS was longest among patients receiving both (not reached [NR]), shorter among those receiving only systemic steroids (SSs) (84.2 months; 95% CI, 40.2 months to NR), and shortest among those who did not experience irAEs (10.3 months; 95% CI, 6-20.1 months) (p < .001). Longer OS was significantly associated with the occurrence of irAEs and the use of SSs with or without ISAs upon multivariable-adjusted analysis (p < .001). Similar results were noted with anti-programmed death 1 (PD-1) monotherapy and combination anti-PD-1 plus anti-cytotoxic T-lymphocyte antigen 4 (CTLA-4) therapy, and with 12-week landmark sensitivity analysis (p = .01). CONCLUSIONS: These findings in patients with melanoma who were treated with ICIs suggest that the use of SSs or ISAs for the management of irAEs is not associated with inferior disease outcomes, which supports the use of these agents when necessary.

A multidisciplinary management algorithm for brain metastases.

The incidence of brain metastases continues to present a management issue despite the advent of improved systemic control and overall survival. While the management of oligometastatic disease (ie, 1-4 brain metastases) with surgery and radiation has become fairly straightforward in the era of radiosurgery, the management of patients with multiple metastatic brain lesions can be challenging. Here we review the available evidence and provide a multidisciplinary management algorithm for brain metastases that incorporates the latest advances in surgery, radiation therapy, and systemic therapy while taking into account the latest in precision medicine-guided therapies. In particular, we argue that whole-brain radiation therapy can likely be omitted in most patients as up-front therapy.

Immune Checkpoint Blockade and Skin Toxicity Pathogenesis.

Immune checkpoint blockade has revolutionized the treatment of multiple tumor types, including melanoma and nonmelanoma skin cancers. The use of immune checkpoint blockade is curtailed by tissue toxicities termed immune-related adverse events (irAEs), which occur most quickly and most often in the skin. We review the rationale for immune checkpoint blockade use, current agents, use in skin cancers, autoimmune manifestations in the skin, and considerations for predictive biomarkers and treatment options on the basis of skin pathogenesis. We also highlight major gaps in the field and the lack of preclinical modeling in the skin. A deeper understanding of irAE pathophysiology may help to uncouple toxicity and efficacy but mandates an interdisciplinary approach, including foundational skin immunology and autoimmune pathogenesis.

The clinical development of obinutuzumab for the treatment of follicular lymphoma.

Impressive progress has been made in recent decades for advanced-stage follicular lymphoma with the availability of anti-CD20 monoclonal antibodies, initially rituximab and more recently obinutuzumab. Obinutuzumab is a unique, third-generation, fully humanized glycoengineered IgG1 type II anti-CD20 monoclonal antibody. It has been shown to have increased antitumor activity compared to rituximab in preclinical studies, including whole-blood B-cell depletion assays, xenograft models, and primate models. This has spurred on the development of obinutuzumab through Phase I/II trials as monotherapy and in combination with chemotherapeutic agents and other targeted therapies. Its efficacy compared to rituximab and in rituximab-refractory disease has led to its continued development and eventual approval for the treatment of follicular lymphoma. Here in this review, we highlight the design and development of obinutuzumab in the treatment of advanced stage grade 1-3A follicular lymphoma and its future directions.

Targeted coating with antigenic peptide renders tumor cells susceptible to CD8(+) T cell-mediated killing.

The potency of immunotherapies targeting endogenous tumor antigens is hindered by immune tolerance. We created a therapeutic agent comprised of a tumor-homing module fused to a functional domain capable of selectively rendering tumor cells sensitive to foreign antigen-specific CD8(+) T cell-mediated immune attack, and thereby, circumventing concerns for immune tolerance. The tumor-homing module is comprised of a single-chain variable fragment (scFv) that specifically binds to mesothelin (Meso), which is commonly overexpressed in human cancers, including ovarian tumors. The functional domain is comprised of the Fc portion of IgG2a protein and foreign immunogenic CD8(+) T cell epitope flanked by furin cleavage sites (R), which can be recognized and cleaved by furin that is highly expressed in the tumor microenvironment. We show that our therapeutic protein specifically loaded antigenic epitope onto the surface of mesothelin-expressing tumor cells, rendering tumors susceptible to antigen-specific cytotoxic CD8(+) T lymphocytes (CTL)-mediated killing in vitro and in vivo. Our findings have important implications for bypassing immune tolerance to enhance cancer immunotherapy.

Emerging human papillomavirus vaccines.

INTRODUCTION: Identification of human papillomavirus (HPV) as the etiologic factor of cervical, anogenital, and a subset of head and neck cancers has stimulated the development of preventive and therapeutic HPV vaccines to control HPV-associated malignancies. Excitement has been generated by the commercialization of two preventive L1-based vaccines, which use HPV virus-like particles (VLPs) to generate capsid-specific neutralizing antibodies. However, factors such as high cost and requirement for cold chain have prevented widespread implementation where they are needed most. AREAS COVERED: Next generation preventive HPV vaccine candidates have focused on cost-effective stable alternatives and generating broader protection via targeting multivalent L1 VLPs, L2 capsid protein, and chimeric L1/L2 VLPs. Therapeutic HPV vaccine candidates have focused on enhancing T cell-mediated killing of HPV-transformed tumor cells, which constitutively express HPV-encoded proteins, E6 and E7. Several therapeutic HPV vaccines are in clinical trials. EXPERT OPINION: Although progress is being made, cost remains an issue inhibiting the use of preventive HPV vaccines in countries that carry the majority of the cervical cancer burden. In addition, progression of therapeutic HPV vaccines through clinical trials may require combination strategies employing different therapeutic modalities. As research in the development of HPV vaccines continues, we may generate effective strategies to control HPV-associated malignancies.

Development of a DNA vaccine targeting Merkel cell polyomavirus.

Merkel cell carcinoma (MCC) is a rare but devastating skin disease that is increasing in incidence within the United States. The poor prognosis of MCC patients and limited understanding of MCC pathogenesis warrants innovative treatments to control MCC. Several lines of evidence have pointed to Merkel cell polyomavirus (MCPyV) as the etiological agent of MCC. In particular, the amino terminus of MCPyV large T antigen (LT) (aa1-258) is expressed in all MCPyV-positive tumors and plays an important role in MCC oncogenesis, rendering it an ideal therapeutic target for vaccination. In the current study, we developed a DNA vaccine encoding MCPyV LT aa1-258 (pcDNA3-LT). Within our pcDNA3-LT DNA vaccine, we identified that MCPyV LT aa136-160 likely contains an LT-specific CD4+ T helper epitope. We have also created an LT-expressing B16/LT tumor model using B16, a murine melanoma cell line, to characterize the potency of our DNA vaccine. Using this tumorigenic B16/LT tumor model, we found that pcDNA3-LT DNA vaccine generates antitumor effects mainly mediated by CD4+ T cells against B16/LT tumors in vaccinated C57BL/6 mice. Thus, immunotherapy using pcDNA3-LT DNA vaccine may represent a promising approach for the control of MCPyV-associated lesions. The B16/LT tumor model further serves as a useful model for testing various vaccine strategies against MCC.

LAH4 enhances CD8+ T cell immunity of protein/peptide-based vaccines.

It is now clear that CD8+ T cells are crucial for therapeutic immunity against chronic viral infections and/or tumors. We reason that a strategy capable of improving CD8+ T cell activation would improve the efficacy of protein-based vaccines, which predominantly generate CD4+ T cell-mediated responses. Herein, we explore the ability of a novel cell-penetrating peptide (CPP), LAH4, to facilitate intracellular delivery of protein-based vaccines adjuvanted with Toll-like receptor 9 agonist CpG oligonucleotide (CpG) to generate enhanced CD8+ T cell immune responses and antitumor effects. LAH4 was found to mediate the intracellular delivery of both protein and nucleotide cargo and facilitate protein internalization using mechanisms involving endosomal acidification and processing through the proteasome pathway, leading to enhanced cross presentation of protein antigen by dendritic cells to CD8+ T cells. LAH4 also improved the internalization of CpG, resulting in NFkB activation, thus potentiating the adjuvant effect of CpG. We found that protein-based vaccine comprised of LAH4 mixed with model antigen and CpG generated significantly improved antigen-specific CD8+ T cell immune responses and/or antitumor effects. Furthermore, we found that LAH4 was able to enhance the ability of a tyrosinase-related protein 2 (TRP-2) peptide-based vaccine to generate TRP2-specific CD8+ T cells and antitumor effects against TRP2-expressing tumors. Thus, our results suggest that CPP technology using LAH4 is able to enhance both protein-based and peptide-based vaccine potency to generate antigen-specific CD8+ T cells and antitumor effects. Our findings serve as an important foundation for future clinical applications of CPP technology to improve protein/peptide-based vaccine potency.

DNA vaccines delivered by human papillomavirus pseudovirions as a promising approach for generating antigen-specific CD8+ T cell immunity.

BACKGROUND: Human papillomavirus (HPV) pseudovirions have recently been shown to deliver DNA efficiently in vivo, resulting in the priming of antigen-specific CD8+ T cells in vaccinated mice. In the current study, we compare the different preparation methods for the generation of HPV pseudovirions for their ability to efficiently infect cells. We also compare the antigen-specific CD8+ T cell immune responses generated by different DNA delivery methods and several commonly used forms of vaccination with that of HPV pseudovirions. RESULTS: We found that the preparation method of pseudovirions is important for the efficient delivery of encapsidated DNA. We have shown that vaccination with DNA encoding model antigen ovalbumin (OVA) delivered by HPV-16 pseudovirions was capable of generating therapeutic antitumor effects against OVA-expressing tumor. In addition, vaccination with DNA encoding OVA delivered by HPV-16 pseudovirions generated the highest number of OVA-specific CD8+ T cells in mice in our system compared to DNA delivered by other delivery methods. We also found that vaccination with OVA DNA delivered by HPV-16 pseudovirions generated the highest number of OVA-specific CD8+ T cells in mice compared to other forms of antigen-specific vaccines. Furthermore, HPV-16 pseudovirions were capable of carrying DNA vaccine encoding clinically relevant antigen, telomerase reverse transcriptase, to generate antigen-specific CD8+ T cell immune responses. CONCLUSIONS: Our data suggest that DNA vaccines delivered by HPV-16 pseudovirions may be advantageous compared to other delivery methods and other forms of antigen-specific vaccines for application to antigen-specific immunotherapy.

HPV pseudovirions as DNA delivery vehicles.

"The ability of HPV pseudovirions to efficiently deliver DNA into cells suggests several potential applications in basic biology, including the characterization of virion biology and measurement of protective neutralizing antibody titers in vitro and in vivo, as well as their employment for more direct medical applications".

Intraperitoneal administration of poly(I:C) with polyethylenimine leads to significant antitumor immunity against murine ovarian tumors.

Ovarian cancer is currently the most lethal gynecologic cancer in the United States. There is an urgent need for the development of innovative therapies against ovarian cancer, such as immunotherapy. The toll-like receptor 3 ligand, polyriboinosinic:polyribocytidylic acid (poly(I:C), has emerged as a promising adjuvant for activating the host immune responses for the control of tumors. We reasoned that a strategy to enhance the intracellular uptake of poly(I:C) will likely improve the poly(I:C) adjuvant effect. Since polyethylenimine (PEI) has been shown to increase the transfection efficiency of nucleic acids, we characterized the antitumor effects in mouse ovarian surface epithelial cells (MOSEC) tumor-bearing mice treated intraperitoneally with poly(I:C) and PEI. We observed that tumor-bearing mice treated with poly(I:C) and PEI generated significantly better therapeutic antitumor effects against MOSEC tumors compared with treatment with poly(I:C) alone. Furthermore, we found that NK cells play a significant role in the antitumor effects generated by treatment with poly(I:C) in combination with PEI. Intraperitoneal administration of poly(I:C) with PEI led to the uptake of poly(I:C) mainly by CD11b+ macrophages, resulting in the high expression of MHC class II and IL-12 (M1 phenotype). In addition, adoptive transfer of CD11b+ macrophages from mice treated with poly(I:C) and PEI was found to lead to increased number of activated NK cells in the recipient mice. Taken together, our data indicate that PEI can potentially be used to improve the uptake of poly(I:C) by CD11b+ macrophages, leading to the activation of NK cells and the control of murine ovarian tumors.

Immunotherapy for cervical cancer: Research status and clinical potential.

The high-risk types of human papillomavirus (HPV) have been found to be associated with most cervical cancers and play an essential role in the pathogenesis of the disease. Despite recent advances in preventive HPV vaccine development, such preventive vaccines are unlikely to reduce the prevalence of HPV infections within the next few years, due to their cost and limited availability in developing countries. Furthermore, preventive HPV vaccines may not be capable of treating established HPV infections and HPV-associated lesions, which account for high morbidity and mortality worldwide. Thus, it is important to develop therapeutic HPV vaccines for the control of existing HPV infection and associated malignancies. Therapeutic vaccines are quite different from preventive vaccines in that they require the generation of cell-mediated immunity, particularly T cell-mediated immunity, instead of the generation of neutralizing antibodies. The HPV-encoded early proteins, the E6 and E7 oncoproteins, form ideal targets for therapeutic HPV vaccines, since they are consistently expressed in HPV-associated cervical cancer and its precursor lesions and thus play crucial roles in the generation and maintenance of HPV-associated disease. Our review covers the various therapeutic HPV vaccines for cervical cancer, including live vector-based, peptide or protein-based, nucleic acid-based, and cell-based vaccines targeting the HPV E6 and/or E7 antigens. Furthermore, we review the studies using therapeutic HPV vaccines in combination with other therapeutic modalities and review the latest clinical trials on therapeutic HPV vaccines.

Therapeutic HPV DNA vaccines.

It is now well established that most cervical cancers are causally associated with HPV infection. This realization has led to efforts to control HPV-associated malignancy through prevention or treatment of HPV infection. Currently, commercially available HPV vaccines are not designed to control established HPV infection and associated premalignant and malignant lesions. To treat and eradicate pre-existing HPV infections and associated lesions which remain prevalent in the U.S. and worldwide, effective therapeutic HPV vaccines are needed. DNA vaccination has emerged as a particularly promising form of therapeutic HPV vaccines due to its safety, stability and ability to induce antigen-specific immunity. This review focuses on improving the potency of therapeutic HPV vaccines through modification of dendritic cells (DCs) by [1] increasing the number of antigen-expressing/antigen-loaded DCs, [2] improving HPV antigen expression, processing and presentation in DCs, and [3] enhancing DC and T cell interaction. Continued improvement in therapeutic HPV DNA vaccines may ultimately lead to an effective DNA vaccine for the treatment of HPV-associated malignancies.

Treatment with cyclooxygenase-2 inhibitors enables repeated administration of vaccinia virus for control of ovarian cancer.

Metastatic ovarian cancer is the leading cause of death among women with gynecologic malignancies in the United States. The lack of effective treatment for patients with advanced ovarian cancer warrants development of innovative therapies. Cancer therapy using oncolytic viruses represents a promising new approach for controlling tumors. Vaccinia virus has been shown to preferentially infect tumor cells but not normal tissue. However, oncolytic therapy using recombinant viruses faces the limitation of viral clearance due to generation of neutralizing antibodies. In the current study, we found that cyclooxygenase-2 (Cox-2) inhibitors circumvented this limitation, enabling repeated administration of vaccinia virus without losing infectivity. We quantified the antivaccinia antibody response using enzyme-linked immunosorbent assay (ELISA) and neutralization assays to show that treatment of Cox-2 inhibitors inhibited the generation of neutralizing antibodies. Furthermore, we showed that combination treatment of Cox-2 inhibitors with vaccinia virus was more effective that either treatment alone in treating MOSEC/luc tumor-bearing mice. Thus, the combination of Cox-2 inhibitors and vaccinia virus represents a potential innovative approach to controlling ovarian tumors.

Therapeutic human papillomavirus vaccines: current clinical trials and future directions.

BACKGROUND: Cervical cancer is the second largest cause of cancer deaths in women worldwide. It is now evident that persistent infection with high-risk human papillomavirus (HPV) is necessary for the development and maintenance of cervical cancer. Thus, effective vaccination against HPV represents an opportunity to restrain cervical cancer and other important cancers. The FDA recently approved the HPV vaccine Gardasil for the preventive control of HPV, using HPV virus-like particles (VLP) to generate neutralizing antibodies against major capsid protein, L1. However, prophylactic HPV vaccines do not have therapeutic effects against pre-existing HPV infections and HPV-associated lesions. Furthermore, due to the considerable burden of HPV infections worldwide, it would take decades for preventive vaccines to affect the prevalence of cervical cancer. Thus, in order to speed up the control of cervical cancer and treat current infections, the continued development of therapeutic vaccines against HPV is critical. Therapeutic HPV vaccines can potentially eliminate pre-existing lesions and malignant tumors by generating cellular immunity against HPV-infected cells that express early viral proteins such as E6 and E7. OBJECTIVE: This review discusses the future directions of therapeutic HPV vaccine approaches for the treatment of established HPV-associated malignancies, with emphasis on current progress of HPV vaccine clinical trials. METHODS: Relevant literature is discussed. RESULTS/CONCLUSION: Though their development has been challenging, many therapeutic HPV vaccines have been shown to induce HPV-specific antitumor immune responses in preclinical animal models and several promising strategies have been applied in clinical trials. With continued progress in the field of vaccine development, HPV therapeutic vaccines may provide a potentially promising approach for the control of lethal HPV-associated malignancies.