Managing toxicities associated with immune checkpoint inhibitors: consensus recommendations from the Society for Immunotherapy of Cancer (SITC) Toxicity Management Working Group.

Cancer immunotherapy has transformed the treatment of cancer. However, increasing use of immune-based therapies, including the widely used class of agents known as immune checkpoint inhibitors, has exposed a discrete group of immune-related adverse events (irAEs). Many of these are driven by the same immunologic mechanisms responsible for the drugs' therapeutic effects, namely blockade of inhibitory mechanisms that suppress the immune system and protect body tissues from an unconstrained acute or chronic immune response. Skin, gut, endocrine, lung and musculoskeletal irAEs are relatively common, whereas cardiovascular, hematologic, renal, neurologic and ophthalmologic irAEs occur much less frequently. The majority of irAEs are mild to moderate in severity; however, serious and occasionally life-threatening irAEs are reported in the literature, and treatment-related deaths occur in up to 2% of patients, varying by ICI. Immunotherapy-related irAEs typically have a delayed onset and prolonged duration compared to adverse events from chemotherapy, and effective management depends on early recognition and prompt intervention with immune suppression and/or immunomodulatory strategies. There is an urgent need for multidisciplinary guidance reflecting broad-based perspectives on how to recognize, report and manage organ-specific toxicities until evidence-based data are available to inform clinical decision-making. The Society for Immunotherapy of Cancer (SITC) established a multidisciplinary Toxicity Management Working Group, which met for a full-day workshop to develop recommendations to standardize management of irAEs. Here we present their consensus recommendations on managing toxicities associated with immune checkpoint inhibitor therapy.

Talimogene laherparepvec (T-VEC) as cancer immunotherapy.

Talimogene laherparepvec (T-VEC) is the first-in-class oncolytic virus immunotherapy for the treatment of cancer and was generated from an attenuated, recombinant herpes simplex virus. T-VEC has demonstrated therapeutic activity in melanoma patients and is being tested in a number of other cancers alone and in combination with standard cancer therapeutics and other immunotherapy agents. This review will discuss the current landscape of melanoma, the construction and application of T-VEC for melanoma along with other indications for T-VEC, as well as highlight some of the novel challenges with oncolytic virus immunotherapy as it enters into clinical practice.

Carcinoembryonic antigen (CEA) presentation and specific T cell-priming by human dendritic cells transfected with CEA-mRNA.

The feasibility of dendritic cells (DC) for cancer immunotherapy after transfection by electroporation with mRNA encoding the human carcinoembryonic antigen (CEA) was investigated. Both, total RNA from the CEA(+) colon cancer cell line SW480 and mRNA transcribed in vitro from cDNA3.1-plasmids (pcDNA3.1+/-HisC) with a CEA-insert (ivt-CEA-mRNA, ivt-CEA/HisC-mRNA) were used. Labelled ivt-CEA-mRNA was detectable in DC by light and electron microscopy and by fluorescence-activated cell-sorting (FACS) even 15 min after electroporation. Four hours after transfection with ivt-CEA/HisC-mRNA, we detected specific expression of CEA and the histidine-tag by immunofluorescence microscopy and by FACS. CEA-specific T lymphocytes were successfully primed by transfected DC and were able to lyse CEA-expressing target cells, even from the CEA-expressing human colon adenocarcinoma cell line SW480. Thus, DC transfected by electroporation with CEA-mRNA are valuable tools for the immunotherapy of CEA(+) tumour entities.

A new mouse model for evaluating the immunotherapy of human colorectal cancer.

A new murine model of human colorectal cancer was generated by crossing human carcinoembryonic antigen (CEA) transgenic mice (H-2K(b)) with adenomatous polyposis coli (Apc1638N) knockout mice (H-2K(b)). The resulting hybrid mice developed gastrointestinal polyps in 6-8 months that progressed to invasive carcinomas with a similar pattern of dysplasia and CEA expression as observed in human colorectal cancer. These animals exhibited incomplete or partial tolerance to CEA as evidenced by delayed growth of CEA-expressing tumors and the inability to inhibit CEA-specific CTL responses. These results have important implications for understanding the role of CEA-specific immunity in human colon cancer patients and suggest that vaccine strategies targeting CEA may be feasible. This model provides a powerful system for evaluating antigen-specific tumor immunity against spontaneous tumors arising in an orthotopic location and permits evaluation of therapeutic vaccine strategies for human colorectal cancer.

Innovative treatments for pancreatic cancer.

Pancreatic cancer is the fifth leading cause of cancer deaths in the United States with little or no impact from conventional treatment options. Significant advances in understanding basic immunology have renewed interest in using immunotherapy to treat pancreatic cancer. Cancer immunotherapy, including humanized MAbs, cytokines, and potent vaccine strategies, has been successful in animal models and is being evaluated in clinical trials. Gene therapy is also being explored using methods to inactivate oncogenes, replace defective tumor suppressor genes, confer enhanced chemosensitivity to tumor cells, and increase immunogenicity of tumor cells. Angiogenesis, an essential step in the growth and metastasis of pancreatic cancer, has been targeted by many antiangiogenic agents. Several clinical trials have been initiated to evaluate the role of these innovative strategies in patients with pancreatic cancer with increasingly sophisticated correlative studies to learn more about the mechanisms of tumor rejection with these agents. The rapid translation of basic science discoveries to clinical trials should result in the development of new effective treatments for patients with pancreatic cancer.

Palmitoylation of caveolin-1 at a single site (Cys-156) controls its coupling to the c-Src tyrosine kinase: targeting of dually acylated molecules (GPI-linked, transmembrane, or cytoplasmic) to caveolae effectively uncouples c-Src and caveolin-1 (TYR-14).

Caveolin-1 was initially identified as a phosphoprotein in Rous sarcoma virus-transformed cells. Previous studies have shown that caveolin-1 is phosphorylated on tyrosine 14 by c-Src and that lipid modification of c-Src is required for this phosphorylation event to occur in vivo. Phosphocaveolin-1 (Tyr(P)-14) localizes within caveolae near focal adhesions and, through its interaction with Grb7, augments anchorage-independent growth and epidermal growth factor-stimulated cell migration. However, the cellular factors that govern the coupling of caveolin-1 to the c-Src tyrosine kinase remain largely unknown. Here, we show that palmitoylation of caveolin-1 at a single site (Cys-156) is required for coupling caveolin-1 to the c-Src tyrosine kinase. Furthermore, upon evaluating a battery of nonreceptor and receptor tyrosine kinases, we demonstrate that the tyrosine phosphorylation of caveolin-1 by c-Src is a highly selective event. We show that Src-induced tyrosine phosphorylation of caveolin-1 can be inhibited or uncoupled by targeting dually acylated proteins (namely carcinoembryonic antigen (CEA), CD36, and the NH(2)-terminal domain of Galpha(i1)) to the exoplasmic, transmembrane, and cytoplasmic regions of the caveolae membrane, respectively. Conversely, when these proteins are not properly targeted or lipid-modified, the ability of c-Src to phosphorylate caveolin-1 remains unaffected. In addition, when purified caveolae preparations are preincubated with a myristoylated peptide derived from the extreme N terminus of c-Src, the tyrosine phosphorylation of caveolin-1 is abrogated; the same peptide lacking myristoylation has no inhibitory activity. However, an analogous myristoylated peptide derived from c-Yes also has no inhibitory activity. Thus, the inhibitory effects of the myristoylated c-Src peptide are both myristoylation-dependent and sequence-specific. Finally, we investigated whether phosphocaveolin-1 (Tyr(P)-14) interacts with the Src homology 2 and/or phosphotyrosine binding domains of Grb7, the only characterized downstream mediator of its function. Taken together, our data identify a series of novel lipid-lipid-based interactions as important regulatory factors for coupling caveolin-1 to the c-Src tyrosine kinase in vivo.

Immucillin H, a powerful transition-state analog inhibitor of purine nucleoside phosphorylase, selectively inhibits human T lymphocytes.

Transition-state theory has led to the design of Immucillin-H (Imm-H), a picomolar inhibitor of purine nucleoside phosphorylase (PNP). In humans, PNP is the only route for degradation of deoxyguanosine, and genetic deficiency of this enzyme leads to profound T cell-mediated immunosuppression. This study reports the biological effects and mechanism of action of Imm-H on malignant T cell lines and on normal activated human peripheral T cells. Imm-H inhibits the growth of malignant T cell leukemia lines with the induction of apoptosis. Imm-H also inhibits activated normal human T cells after antigenic stimulation in vitro. However, Imm-H did not inhibit malignant B cells, colon cancer cell lines, or normal human nonstimulated T cells, demonstrating the selective activity of Imm-H. The effects on leukemia cells were mediated by the cellular phosphorylation of deoxyguanosine and the accumulation of dGTP, an inhibitor of ribonucleotide diphosphate reductase. Cells were protected from the toxic effects of Imm-H when deoxyguanosine was absent or when deoxycytidine was present. Guanosine incorporation into nucleic acids was selectively blocked by Imm-H with no effect on guanine, adenine, adenosine, or deoxycytidine incorporation. Imm-H may have clinical potential for treatment of human T cell leukemia and lymphoma and for other diseases characterized by abnormal activation of T lymphocytes. The design of Imm-H from an enzymatic transition-state analysis exemplifies a powerful approach for developing high-affinity enzyme inhibitors with pharmacologic activity.

Increased carcinoembryonic antigen expression in cervical intraepithelial neoplasia grade 3 and in cervical squamous cell carcinoma.

Carcinoembryonic antigen (CEA) is a highly glycosylated cell surface protein that is overexpressed in a variety of human tumors and has been used as a tumor marker for disease progression in colorectal cancer patients. Recently, CEA has been used as a target for vaccine therapy against advanced CEA-expressing colonic adenocarcinomas. Previous reports have found elevated serum CEA levels in patients with cervical cancer, although this did not correlate with disease progression. In this study, cervical biopsy specimens from patients with normal histology, cervical intraepithelial neoplasia (CIN) grades 1 to 3, cervical squamous cell carcinoma (SCC), and adenocarcinoma were evaluated for CEA expression by immunohistochemistry by using the monoclonal antibody COL-1. Staining intensity was graded on a scale of 0 to 3 and was correlated with histologic diagnoses. CEA staining intensity was significantly increased in high-grade squamous lesions (CIN III and SCC) compared with normal cervical mucosa and CIN grades I or II (P <.0001). There was a linear correlation between grade of lesion and staining intensity (r = 0.71). CEA expression increased most significantly between CIN grades 2 to 3. Only 1 of 7 primary cervical adenocarcinomas expressed CEA. Only 1 of 10 patients with high CEA expression in their tumors by immunohistochemistry had elevated serum CEA. We thus have shown that lesional CEA expression increases in CIN 3 and SCC without elevations in serum CEA. CEA expression may be a useful diagnostic tool and a useful marker for identifying those at risk for progressive cervical neoplasia. HUM PATHOL 31:1357-1362.

Phase I clinical trial of a recombinant canarypoxvirus (ALVAC) vaccine expressing human carcinoembryonic antigen and the B7.1 co-stimulatory molecule.

The generation of cytotoxic effector T cells requires delivery of two signals, one derived from a specific antigenic epitope and one from a costimulatory molecule. A phase I clinical trial was conducted with a non-replicating canarypoxvirus (ALVAC) constructed to express both human carcinoembryonic antigen (CEA) and the B7.1 costimulatory molecule. This was the first study in cancer patients to determine if the delivery of costimulation with a tumor vaccine was feasible and improved immune responses. Three cohorts of six patients, each with advanced CEA-expressing adenocarcinomas, were treated with increasing doses of an ALVAC-CEA-B7.1 vaccine (4.5 x 10(6), 4.5 x 10(7), and 4.5 x 10(8) plaque-forming units, PFU). Patients were vaccinated by intramuscular injection every 4 weeks for 3 months and monitored for side-effects, tumor growth and anti-CEA immune responses. ALVAC-CEA-B7.1 at doses up to 4.5 x 10(8) PFU was given without evidence of significant toxicity or autoimmune reactions. Three patients experienced clinically stable disease that correlated with increasing CEA-specific precursor T cells, as shown by in vitro interferon-gamma enzyme-linked immunoassay spot tests (ELISPOT). These three patients underwent repeated vaccination resulting in augmented CEA-specific T cell responses. This study represents the first use of costimulation to enhance antitumor vaccines in cancer patients. This approach resulted in CEA-specific immunity associated with stable diseases in three patients. This study also demonstrated that CEA-specific T cell responses could be sustained by repeated vaccinations. Although the number of patients was small, the addition of B7.1 to virus-based vaccines may improve immunological and stable diseases to vaccination against tumor-associated antigens with tolerable toxicity.

Clinical infection control in gene therapy: a multidisciplinary conference.

Gene therapy is being studied for the treatment of a variety of acquired and inherited disorders. Retroviruses, adenoviruses, poxviruses, adeno-associated viruses, herpesviruses, and others are being engineered to transfer genes into humans. Treatment protocols using recombinant viruses are being introduced into clinical settings. Infection control professionals will be involved in reviewing the safety of these agents in their clinics and hospitals. To date, only a limited number of articles have been written on infection control in gene therapy, and no widely available recommendations exist from federal or private organizations to guide infection control professionals. The goals of the conference were to provide a forum where gene therapy experts could share their perspectives and experience with infection control in gene therapy and to provide an opportunity for newcomers to the field to learn about issues specific to infection control in gene therapy. Recommendations for infection control in gene therapy were proposed.

Strategies for cancer therapy using carcinoembryonic antigen vaccines.

Advances in molecular biology and immunology have renewed interest in the development of vaccines for the treatment or prevention of cancer. Research over the past 10 years has focused on the identification of suitable tumour antigens to use as targets for a variety of vaccine strategies. Carcinoembryonic antigen (CEA) was one of the first tumour antigens described, and is commonly expressed by a wide range of adenocarcinomas. Recent studies have identified several human-leukocyte-antigen-restricted epitopes (short peptides) within the CEA protein that can be recognised by human T lymphocytes (T cells). Although CEA-expressing tumour cells are generally weakly recognised by the immune system, several new strategies have been used to enhance immune responses against CEA. This includes using antibodies directed against CEA; inserting the CEA gene into recombinant viruses and bacteria as viral and bacterial vaccines; pulsing the CEA protein, peptides, DNA or RNA onto dendritic cells (specialised antigen-presenting cells); and combining CEA vaccines with cytokines or co-stimulatory molecules to increase vaccine effectiveness. Other factors that might be important in establishing systemic immunity against CEA are the dose, route, timing, and choice of vector and adjuvants for vaccine administration. Further research in understanding the fundamental processes involved in tumour-cell recognition by the immune system, better animal models, and improved clinical trial designs will help to define the full potential of CEA as a target for cancer vaccine development.

Interleukin-10 enhances the therapeutic effectiveness of a recombinant poxvirus-based vaccine in an experimental murine tumor model.

Interleukin-10 (IL-10) has a wide range of in vivo biological activities and is a key regulatory cytokine of immune-mediated inflammation. The authors found that murine IL-10 given 12 hours after a recombinant vaccinia virus (rVV) containing the LacZ gene significantly enhanced the treatment of mice bearing 3-day-old pulmonary metastases expressing beta-galactosidase. Because IL-10 has been shown to inhibit the functions of key elements of both innate and acquired immune responses, the authors hypothesized that IL-10 might act by inhibiting clearance of the rVV, thus prolonging exposure to the experimental antigen. However, evidence that IL-10 was not acting primarily through such negative regulatory mechanisms included the following: (a) IL-10 also enhanced the therapeutic effectiveness of a recombinant fowlpox virus, which cannot replicate in mammalian cells; (b) Titers of rVV in immunized mice were lower, not higher; and (c) Although IL-10 did not alter levels of anti-vaccinia anti-bodies or natural killer cell activity, rVV-primed mice treated with IL-10 had enhanced vaccinia-specific cytotoxic T-lymphocyte activity. Thus, IL-10 enhanced the function of a recombinant poxvirus-based anti-cancer vaccine and may represent a potential adjuvant in the vaccination against human cancers using recombinant poxvirus-based vaccines.

Enterocutaneous fistula in cancer patients: etiology, management, outcome, and impact on further treatment.

Enterocutaneous fistulae that develop in patients with cancer represent a difficult management situation, which is often complicated by prior treatment including surgery, radiation therapy, and chemotherapy. A fistula may in turn delay potentially beneficial treatment of the underlying malignancy. To provide a better understanding of this problem, we reviewed the National Institutes of Health experience with enterocutaneous fistulae in adult patients with cancer. The medical records of patients with cancer who developed a fistula from the gastrointestinal tract during the period 1980 through 1994 were reviewed. Etiology, management, outcome, and impact on further treatment were assessed. Twenty-five patients with gastrointestinal fistulae were identified. The most common primary tumor site was the colon/rectum in males and the ovary in women. The majority of patients had metastatic disease at diagnosis and a history of prior therapy and presented with anorexia and weight loss. The fistula was usually single, most commonly developed from the jejunum/ileum (13 patients) or colon/rectum (6 patients), and occurred postoperatively after procedures on the small bowel (10 patients) or colon (8 patients). Malnutrition and sepsis developed in 60 per cent of patients. Thirty-day mortality was 16 per cent and correlated with prior radiation therapy, location and output from the fistula, and hypoalbuminemia. An enterocutaneous fistula negatively impacted on the provision of further therapy for the majority of patients (63%). Enterocutaneous fistula in the patient with cancer occurs most frequently in the setting of extensive prior therapy and is associated with prolonged morbidity. Identification of high-risk patients and early management of fistulas once they develop may prevent delays in subsequent cancer therapy and decrease morbidity.

Splenectomy in a child with chronic Mycobacterium avium complex infection and splenic sequestration.

Mycobacterium avium complex infections (MAC) are being reported with increasing frequency in immunocompromised patients. When these infections become resistant to standard antibiotic therapy, treatment with interferon-gamma (IFN-gamma) can be helpful. Pain, fever, splenic enlargement, and cytopenias caused by splenic sequestration developed during IFN-gamma treatment in a 9-year-old boy and were successfully treated by splenectomy. The development of IFN-gamma-induced splenic sequestration and cytopenias in MAC-infected patients represents a new indication for splenectomy.

Results of a phase I trial of a recombinant vaccinia virus that expresses carcinoembryonic antigen in patients with advanced colorectal cancer.

BACKGROUND: The inadequacy of systemic treatments of advanced colorectal cancer has aroused interest in biologic therapy. Recent animal models have demonstrated the efficacy and safety of a recombinant vaccine that contains vaccinia and the gene for carcinoembryonic antigen (rV-CEA). METHODS: A phase I clinical trial of rV-CEA was conducted to assess vaccine toxicities, the maximum tolerated dosage, resulting immune activities, and tumour responses. A dose-escalation protocol was devised for three concentrations. Six patients per dosage were each to receive three vaccinations. RESULTS: Seventeen patients with advanced colorectal cancer received a total of 44 vaccinations. Mild local and systemic reactions-comparable to those seen with vaccinia alone-were observed and were typically associated with the first vaccination. No significant complications or deaths were caused by the rV-CEA. In particular, no autoimmune colitis developed, nor did leukopenia occur, despite some homology between CEA and leukocyte antigens. All three vaccine concentrations were equally well tolerated. Most patients demonstrated tumor progression by clinical and radiographic parameters and by CEA levels. Immune assays are pending. CONCLUSIONS: This phase I trial demonstrated the safety of rV-CEA in patients with advanced colorectal cancer. Future clinical studies are warranted and will likely be influenced by investigations of the immune responses to the vaccine.