A Peptide-Duocarmycin Conjugate Targeting the Thomsen-Friedenreich Antigen Has Potent and Selective Antitumor Activity.

Solid-phase synthesis allowed the rapid generation of a peptide-drug conjugate. A peptide targeting the Thomsen-Friedenreich antigen (TFα) was conjugated to the alkylating subunit of the potent cytotoxin duocarmycin SA. The compound, containing a cathepsin B cleavable linker, was shown to be active and selective against TFα expressing tumor cell lines.

Use of Granulocyte-colony Stimulating Factor During Chemotherapy and Its Association With CA27.29 and Circulating Tumor Cells-Results From the SUCCESS A Trial.

BACKGROUND: Little is known about the effect of granulocyte colony-stimulating factor (G-CSF) treatment during adjuvant chemotherapy on prognostic markers. The present study explored the association between G-CSF and changes in cancer antigen (CA)27.29 and circulating tumor cell (CTC) levels during therapy. PATIENTS AND METHODS: A total of 3754 node-positive or high-risk node-negative early-stage breast cancer patients were treated within the SUCCESS-A trial (simultaneous study of gemcitabine-docetaxel combination adjuvant treatment, as well as extended bisphosphonate and surveillance-trial). CA27.29 and CTCs were determined before the start and within 6 weeks after the end of chemotherapy. RESULTS: Overall, 1324 of the 2646 patients (50.0%) available for analysis had ≥ 1 G-CSF applications during chemotherapy. G-CSF application was significantly associated with CA27.29 status before and after chemotherapy (χ2 = 30.6, df = 3; P < .001), because 238 patients (18.0%) with G-CSF treatment but only 146 (11.0%) without G-CSF treatment switched from a negative CA27.29 status before to a positive CA27.29 status after chemotherapy. In addition, patients with G-CSF application showed a significantly greater increase in CA27.29 levels after chemotherapy compared with patients without any G-CSF application during chemotherapy (Mann-Whitney U test; Z = -7.81, P < .001). No significant association was found between G-CSF application and CTC status before or after chemotherapy (χ2 = 1.2, df = 3; P = .75). CONCLUSION: Cautious interpretation is needed regarding elevated levels of MUC-1-derived tumor markers such as CA27.29 shortly after adjuvant chemotherapy when G-CSF has been given, because G-CSF treatment was associated with increased CA27.29 levels after chemotherapy.

Cancer vaccines: Enhanced immunogenic modulation through therapeutic combinations.

Therapeutic cancer vaccines have gained significant popularity in recent years as new approaches for specific oncologic indications emerge. Three therapeutic cancer vaccines are FDA approved and one is currently approved by the EMA as monotherapy with modest treatment effects. Combining therapeutic cancer vaccines with other treatment modalities like radiotherapy (RT), hormone therapy, immunotherapy, and/or chemotherapy have been investigated as a means to enhance immune response and treatment efficacy. There is growing preclinical and clinical data that combination of checkpoint inhibitors and vaccines can induce immunogenic intensification with favorable outcomes. Additionally, novel methods for identifying targetable neoantigens hold promise for personalized vaccine development. In this article, we review the rationale for various therapeutic combinations, clinical trial experiences, and future directions. We also highlight the most promising developments that could lead to approval of novel therapeutic cancer vaccines.

Phase 1 experience with an anti-glycotope monoclonal antibody, RAV12, in recurrent adenocarcinoma.

PURPOSE: RAV12 is a high affinity, internalizing, chimeric IgG1 monoclonal antibody that binds RAAG12, a novel primate-restricted N-linked carbohydrate epitope present on multiple cell surface proteins. RAAG12 is highly expressed on many adenocarcinomas, particularly those of gastrointestinal origin. A phase 1 dose-escalation safety and pharmacokinetics trial was conducted in patients with metastatic or recurrent adenocarcinomas. EXPERIMENTAL DESIGN: RAV12 was initially given i.v. weekly x4, then by fractionated dosing twice or thrice weekly. Thirty-three patients were treated in the dose escalation segment of the trial in the following cohorts: 0.3 mg/kg qw (6), 1.0 mg/kg qw (8), 1.5 mg/kg qw (7); and 0.5 mg/kg biw (3), 0.75 mg/kg biw (3), and 0.5 mg/kg tiw (6). Twenty patients were enrolled in a maximum tolerated dose cohort expansion at 0.75 mg/kg biw. RESULTS: Two clinical syndromes were associated with drug administration: abdominal cramping pain with diarrhea, and asymptomatic, self-limited increases of liver function tests. These effects were partially ameliorated with fractionated dosing. Pharmacokinetics was dose dependent. Maximum concentration was reduced, whereas area under the concentration versus time curve was maintained with fractionated dosing. One patient with colorectal cancer experienced a durable partial remission, with a time to progression (TTP) of >8 months. Three additional patients experienced a TTP of >4 months. CONCLUSIONS: RAV12 has activity in recurrent adenocarcinomas. However, the safety profile of the antibody seems to preclude the delivery of highly efficacious doses. Re-engineering the molecule to remove FcRn binding (while maintaining FcgammaR binding) and to humanize it may improve the toxicity profile and efficacy.

Mouse-human chimeric anti-Tn IgG1 induced anti-tumor activity against Jurkat cells in vitro and in vivo.

Tn-antigen (alpha-N-acetyl-galactosamine(GalNAc)-Ser/Thr) is a cancer-associated carbohydrate antigen expressed in various epithelial and hematological cancers, and although a number of anti-Tn IgG and IgM antibodies have been generated, they have not been fully validated for cancer immunotherapy. In this study, we generated a novel murine anti-Tn IgG1 monoclonal antibody, KM3413, by immunization of mucins purified from a culture supernatant of LS180: a human colon cancer cell line. The binding of KM3413 was detected against consecutive Tn-antigens (Tn3 and Tn2), but not against monovalent antigens (Tn1). The affinity (K(D)) of KM3413 was determined to be about 10(-7) M with BIAcore. Cross-reactivity against type-A blood antigen, which shares a sugar residue, alpha-linked GalNAc, with Tn-antigen, was not detected. Next, we generated mouse-human chimeric IgG1 of KM3413 (cKM3413) and evaluated its anti-tumor activities against Jurkat: a human T-lymphoid leukemia cell line. In vitro assay revealed that cKM3413 induced antibody-dependent cellular cytotoxicity (ADCC) and direct killing activity with cross-link antibody. Furthermore, treatment of cKM3413 (1 or 10 mg/kg) showed significantly better survival of Jurkat-inoculated C.B-17/lcr-scid Jcl mice compared with controls using PBS treatment (p<0.001). These results suggest that humanized antibody against clustered Tn-antigens is a promising therapeutic antibody against Tn-positive cancers.

Immunotherapy using fusions of autologous dendritic cells and tumor cells showed effective clinical response in a patient with advanced gastric carcinoma.

Immunotherapy using tumor antigen-loaded dendritic cells is a new approach for the treatment of various types of malignant tumors. Here, we describe a patient with advanced gastric carcinoma who received immunotherapy using fused autologous dendritic cells and carcinoma cells (fusions) and showed effective clinical responses to the treatment. A 74-year-old man showed massive ascitic effusion due to peritonitis carcinomatosa after surgical operation for gastric carcinoma. A gastric carcinoma cell line was established from the patient's tumor tissue. Dendritic cells were obtained by cultivation of the adherent cell fraction of the patient's peripheral blood mononuclear cells (PBMCs) with granulocyte macrophage-colony stimulating factor, interleukin-4, and tumor necrosis factor-alpha. The cells were mixed with irradiated tumor cells and treated with 50% polyethyleneglycol (PEG) for the generation of fusions, as described previously. The PEG-treated cells were injected subcutaneously every 2 weeks. Low-grade fever was observed after the first and second treatments. After the third treatment, ascitic effusion and leg edema decreased markedly, without any other treatments. Serum levels of carcinoembryonic antigen (CEA) and carbohydrate antigen (CA) 19-9 decreased to levels lower than those at the initiation of treatment. PBMCs collected after the fifth treatment elicited cytotoxic activity against autologous tumor cells. Although treatment was continued in the same way, recurrence of the disease was observed about 5 months after the start of the treatment. This is the first report of immunotherapy utilizing fusions of autologous dendritic cells and tumor cells resulting in effective clinical responses in advanced gastric carcinoma, without severe adverse effects.

[Changes in the levels of tumor markers in those working with different chemically active substances]. / Izmenenie urovnei opukholevykh markerov u rabotaiushchikh s razlichnymi khimicheski aktivnymi veshchestvami.

Groups at risk for malignant neoplasia were identified among workmen occupationally exposed to different chemical substances, using immunoradiometric and enzyme immunoassays of tumor-associated antigens. Exposure to the above occupational hazard was found to affect the workmen and cause certain chronic illness accompanied by some increase in concentration of a number of tumoral markers. Increase in tumour antigens suggests indirectly that the chemical substances may have carcinogenic activity. We have every reason to recommend these tests as an additional method for identification of groups at high risk for subsequent development of tumours in the digestive system and reproductive organs of persons occupationally exposed to chemical substances.

Retinoic-acid-induced augmentation of molecular species carrying sialosyl Lewis(a) antigen in colorectal-carcinoma cell cultures.

In order to study the effects of vitamin-A metabolites on long-term carcinoma-antigen secretion, colorectal-carcinoma cells SW1116 were cultured on membrane filters in totally synthetic media with 0 to 2.6 microM retinoic acid (RA). RA altered cell division, cell size and soluble-sialosyl Le(a) (S-Le(a) secretion and S-Le(a) accumulation within cells and apical-membrane domains. Cultures treated with RA for 10-12 days grew to lower cell densities (60% of controls) and contained more protein per cell (140% of controls). RA treated cells also had 5-fold higher levels of S-Le(a) in cells and secreted 9-fold more S-Le(a) into culture media assayed per 24 hr by (ELISA) 19-9 monoclonal antibody binding. As total media S-Le(a) increased, polarity of non-lipid S-Le(a) antigen secretion increased toward the interior (apical) media. High-performance thin-layer immunobinding showed that ganglioside S-Le(a) was higher in RA-fed cells, but could not be detected in apical media of RA-fed or control cells after 24 hr. Western blots indicated that non-lipid sialosyl Lewis(a) was bound to 150- to 180-kDA molecular species principally in cells, but 210- to 300-kDa molecular species appeared in the non-lipid extract of media. Thus, the above RA alterations, monitored by 3 immunochemical techniques, include up to 9-fold stimulation of "constitutive" 150- to 300-kDa sialosyl-Lewis(a) secretion, but ganglioside Lewis(a) is sorted differently and retained by apical membranes.

Dynamic test with recombinant interferon-alpha-2b: effect on 90K and other tumour-associated antigens in cancer patients without evidence of disease.

We have previously shown that a short course of recombinant interferon-alpha-2b (rIFN-alpha-2b) (3 million units day for 5 days) for patients with primary gynaecologic malignancies was able to increase the circulating levels of a newly discovered tumour associated antigen, termed 90K. In this study, we have investigated the effects of the same modality of administration of rIFN-alpha-2b in 62 patients with breast and colorectal cancer whose primary tumour was surgically removed 1 month before and who were without evidence of disease (NED) at the time of the study. A significant increase of 90K serum concentration was already observed 24 h after the first r-IFN-alpha-2b injection and persisted throughout the investigational period. The increase was more pronounced in patients with a basal 90K-negative than a 90K-positive assay. Of 54 patients who started the test with a 90K negative assay, 17 (31%) shifted to a positive assay after rIFN-alpha-2b. Twenty-eight of 62 (45%) patients exhibited a 90K value above the mean increment of the whole population. The serum levels of CEA, CA-15-3, CA 19-9, and alpha-fetoprotein measured in the same serum samples were not modified. After 2 years of follow-up, ten patients relapsed. Six of them showed a 90K increase above the mean increment of the whole population. As with ovarian cancer, the increase of 90K following r-IFN-alpha-2b administration might be of importance for the early detection of disease recurrence in clinically NED breast and colon cancer patients.

Effects of interferon gamma on the proliferation and modulation of cell-surface structures of human ovarian carcinoma cell lines.

Platinum-containing regimens are very effective in the primary treatment of ovarian cancer. However, upon subsequent treatment most tumors develop multidrug resistance. The clinical application of biological response modifiers like interferon gamma (IFN gamma) in advanced ovarian cancer is therefore of increasing interest. Permanent ovarian cancer cell lines are suitable for investigating the mode of action and the potential clinical effectiveness of such response modifiers. IFN gamma is known to modulate many cellular functions. In this study it was compared for its antiproliferative and antigen-modulatory activity on the expression of tumor-associated (CA-125, HMFG, CEA) and major histocompatibility complex (MHC) class I and II antigens as well as of the epidermal growth factor (EGF) receptor on 20 newly established human ovarian carcinoma cell lines. IFN gamma in concentrations of 10, 50 and 100 U/ml was used to study its antigen-modulatory effect, and at additional 1 U/ml and 1000 U/ml to assess its antiproliferative effect on the cells. The cells were incubated with IFN for 4 days. Two cell lines showed strong antiproliferative activity even at minimal doses (up to 50 U/ml). Intermediate growth inhibition between 34% and 84% was observed in 15 cell lines with higher doses. Three lines were resistant to IFN gamma. Independent of the antiproliferative effect, IFN gamma enhanced the expression of MHC class I and MHC class II in nearly all cell lines. Upregulation was also observed for most of the tumor-associated antigens (TAA) and EGF receptor expression. A down-regulation was noticed but rarely. The fact that IFN gamma showed an antiproliferative activity on the majority of the cell lines is of clinical relevance. The in vitro modulation of cell-surface determinants by IFN gamma warrants special attention. The enhanced expression of TAA and MHC antigens can improve immunogenicity of the tumor cells and may explain the therapeutic effects observed under IFN therapy in ovarian cancer. By contrast, enhanced expression of the EGF receptor, often associated with poor patient survival rates, may be an undesirable side-effect of IFN therapy.

A phase II study of crisnatol mesylate in patients with ovarian carcinoma.

Fourteen patients with advanced ovarian cancer received a 72 hour infusion of a new DNA intercalator, crisnatol mesylate, administered intravenously. There was no evidence of antitumor efficacy. A syndrome of nausea and vomiting associated with vertigo, dizziness and ataxia was observed in nearly all patients. Two of the patients developed severe CNS toxicity manifested in one by a grand-mal seizure and in the other by peripheral neuropathy. Further explorations into the potential efficacy of crisnatol mesylate administered intraperitoneally are underway.