Treatment of advanced pancreatic carcinoma with 90Y-Clivatuzumab Tetraxetan: a phase I single-dose escalation trial

PURPOSE

Humanized antibody hPAM4 specifically binds a mucin glycoprotein expressed in pancreatic adenocarcinomas. This phase I study evaluated a single dose of (90)Y-clivatuzumab tetraxetan ((90)Y-labeled hPAM4) in patients with advanced pancreatic cancer.

EXPERIMENTAL DESIGN

Twenty-one patients (4 stage III; 17 stage IV) received (111)In-hPAM4 for imaging and serum sampling before (90)Y-hPAM4. Study procedures evaluated adverse events, safety laboratories, computed tomography (CT) scans, biomarkers, pharmacokinetics, radiation dosimetry, and immunogenicity (HAHA).

RESULTS

(111)In-hPAM4 showed normal biodistribution with radiation dose estimates to red marrow and solid organs acceptable for radioimmunotherapy and with tumor targeting in 12 patients. One patient withdrew before (90)Y-hPAM4; otherwise, 20 patients received (90)Y doses of 15 (n = 7), 20 (n = 9), and 25 mCi/m(2) (n = 4). Treatment was well tolerated; the only significant drug-related toxicities were (NCI CTC v.3) grade 3 to 4 neutropenia and thrombocytopenia increasing with (90)Y dose. There were no bleeding events or serious infections, and most cytopenias recovered to grade 1 within 12 weeks. Three patients at 25 mCi/m(2) encountered dose-limiting toxicity with grade 4 cytopenias more than 7 days, establishing 20 mCi/m(2) as the maximal tolerated (90)Y dose. Two patients developed HAHA of uncertain clinical significance. Most patients progressed rapidly and with CA19-9 levels increasing within 1 month of therapy, but 7 remained progression-free by CT for 1.5 to 5.6 months, including 3 achieving transient partial responses (32%-52% tumor diameter shrinkage).

CONCLUSION

(90)Y-Clivatuzumab tetraxetan was well tolerated with manageable hematologic toxicity at the maximal tolerated (90)Y dose, and is a potential new therapeutic for advanced pancreatic cancer.

Specific targeting of nasopharyngeal carcinoma cell line CNE1 by C225-conjugated ultrasmall superparamagnetic iron oxide particles with magnetic resonance imaging

An accurate definition of clinical target volume (CTV) is essential for the application of radiotherapy in nasopharyngeal carcinoma (NPC) treatment. A novel epidermal growth factor receptor (EGFR)-targeting contrast agent (C225-USPIO) was designed by conjugating ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles with cetuximab (C225), to non-invasively define the CTV of tumor. The immunobinding activity of C225-USPIO to NPC cell line CNE1 was confirmed by flow cytometry and immunofluorescence. The time-dependent accumulation of C225-USPIO in CNE1 cells was evaluated using Prussian blue staining. Targeted internalization and subcellular localization of C225-USPIO was confirmed by transmission electron microscope. The results indicated that C225-USPIO specifically bound to EGFR on the surface of CNE1 cells and was taken up into the cell. The uptake of C225-USPIO by CNE1 cells increased significantly with time, when compared with human IgG-USPIO. In addition, 4.7 T magnetic resonance imaging (MRI) revealed that C225-USPIO had a capacity to accumulate in the CNE1 cells, with a resultant marked decrease in MRI T2-weighted signal intensity over time. These findings imply that C225-USPIO has the potential as an MRI contrast agent and can be employed to non-invasively detect early-stage NPC with EGFR overexpression. This provides sufficient theoretical basis for commencing in vivo experiments with the compound.

Stable IgG-like bispecific antibodies directed toward the type I insulin-like growth factor receptor demonstrate enhanced ligand blockade and anti-tumor activity

Bispecific antibodies (BsAbs) target multiple epitopes on the same molecular target or different targets. Although interest in BsAbs has persisted for decades, production of stable and active BsAbs has hindered their clinical evaluation. Here, we describe the production and characterization of tetravalent IgG-like BsAbs that combine the activities of allosteric and competitive inhibitors of the type-I insulin-like growth factor receptor (IGF-1R). The BsAbs, which were engineered for thermal stability, express well, demonstrate favorable biophysical properties, and recognize both epitopes on IGF-1R. Only one BsAb with a unique geometry, denoted BIIB4-5scFv, was capable of engaging all four of its binding arms simultaneously. All the BsAbs (especially BIIB4-5scFv) demonstrated enhanced ligand blocking over the single monoclonal antibodies (mAbs), particularly at high ligand concentrations. The pharmacokinetic profiles of two IgG-like BsAbs were tested in nude mice and shown to be comparable with that of the parental mAbs. The BsAbs, especially BIIB4-5scFv, demonstrated an improved ability to reduce the growth of multiple tumor cell lines and to inhibit ligand-induced IGF-1R signaling in tumor cells over the parental mAbs. BIIB4-5scFv also led to superior tumor growth inhibition over its parental mAbs in vivo. In summary, BsAbs that bridge multiple inhibitory mechanisms against a single target may generally represent a more effective strategy for intervention in oncology or other indications compared with traditional mAb therapy.

Single domain intracellular antibodies from diverse libraries: emphasizing dual functions of LMO2 protein interactions using a single VH domain

Interfering intracellular antibodies are valuable for biological studies as drug surrogates and as potential macromolecular drugs per se. Their application is still limited because of the difficulty of acquisition of functional intracellular antibodies. We describe the use of the new intracellular antibody capture procedure (IAC(3)) to facilitate direct isolation of functional single domain antibody fragments using four independent target molecules (LMO2, TP53, CRAF1, and Hoxa9) from a set of diverse libraries. Initially, these have variability in only one of the three antigen-binding CDR regions of VH or VL and first round single domains are affinity matured by iterative randomization of the two other CDRs and reselection. We highlight the approach using a single domain binding to LMO2 protein. Our results show that interfering with LMO2 protein function demonstrates a role specifically in erythroid differentiation, confirm a necessary and sufficient function for LMO2 as a cancer therapy target in T-cell neoplasia and allowed for the first time production of soluble recombinant LMO2 protein by co-expression with intracellular domain antibodies. Co-crystallization of LMO2 and the anti-LMO2 VH protein was successful. These results demonstrate that this third generation IAC(3) offers a robust toolbox for various biomedical applications and consolidates functional features of the LMO2 protein complex, which includes the importance of Lmo2-Ldb1 protein interaction.

On the immunostimulatory hypothesis of cancer

There is a rather generalized belief that the worst possible outcome for the application of immunological therapies against cancer is a null effect on tumor growth. However, a significant body of evidence summarized in the immunostimulatory hypothesis of cancer suggests that, upon certain circumstances, the growth of incipient and established tumors can be accelerated rather than inhibited by the immune response supposedly mounted to limit tumor growth. In order to provide more compelling evidence of this proposition, we have explored the growth behavior characteristics of twelve murine tumors -most of them of spontaneous origin- arisen in the colony of our laboratory, in putatively immunized and control mice. Using classical immunization procedures, 8 out of 12 tumors were actually stimulated in "immunized" mice while the remaining 4 were neither inhibited nor stimulated. Further, even these apparently non-antigenic tumors could reveal some antigenicity if more stringent than classical immunization procedures were used. This possibility was suggested by the results obtained with one of these four apparently non-antigenic tumors: the LB lymphoma. In effect, upon these stringent immunization pretreatments, LB was slightly inhibited or stimulated, depending on the titer of the immune reaction mounted against the tumor, with higher titers rendering inhibition and lower titers rendering tumor stimulation. All the above results are consistent with the immunostimulatory hypothesis that entails the important therapeutic implications -contrary to the orthodoxy- that, anti-tumor vaccines may run a real risk of doing harm if the vaccine-induced immunity is too weak to move the reaction into the inhibitory part of the immune response curve and that, a slight and prolonged immunodepression -rather than an immunostimulation- might interfere with the progression of some tumors and thus be an aid to cytotoxic therapies.

A new rapid desensitization protocol for chemotherapy agents

BACKGROUND

Desensitization has been used for some decades to treat patients with the allergenic drug when an alternative drug with similar efficacy and safety is not available. We present the results from a series of oncology patients desensitized at our hospital during the last 2 years.

OBJECTIVE

To assess the efficacy of a new desensitization protocol in patients allergic to chemotherapy drugs.

METHODS

We performed an observational retrospective study of 11 women (6 breast cancer and 5 ovarian cancer) who underwent our desensitization protocol. Four patients had immediate reactions to carboplatin, 3 to docetaxel, 3 to paclitaxel, and 1 to both docetaxel and paclitaxel. Premedication was administered in all cases. A 5-step protocol based on 5 different dilutions of the drugs was used.

RESULTS

We performed 39 desensitization procedures: 14 to carboplatin, 3 to oxaliplatin, 16 to docetaxel, and 6 to paclitaxel. Eight patients tolerated the full dose in 36 procedures. One patient suffered an anaphylactic reaction to carboplatin that reverted with treatment. One patient had dyspnea after a paclitaxel cycle. One patient experienced dyspnea due to chronic pulmonary thromboembolism related to her disease.

CONCLUSION

Desensitization is a useful procedure in patients who are allergic to their chemotherapy agents.

Bisphosphonates' antitumor activity: an unravelled side of a multifaceted drug class

Bisphosphonates, especially nitrogen-containing bisphosphonates (N-BPs), are widely used to preserve and improve bone health in patients with cancer because they inhibit osteoclast-mediated bone resorption. In addition to their effects on bone, preclinical evidence strongly suggests that N-BPs exert anticancer activity without the involvement of osteoclasts by interacting with macrophages, endothelial cells and tumor cells, and by stimulating the cytotoxicity of γδ T cells, a subset of human T cells. This review examines the current insights and fronts of ongoing preclinical research on N-BPs' antitumor activity.

Pharmacological inhibition of TGFβ as a strategy to augment the antitumor immune response

There is considerable evidence suggesting that a variety of malignancies utilize the TGFβ cytokine to evade immune surveillance mechanisms to facilitate tumor growth and metastatic progression. The recently developed large- and small-molecule TGFβ inhibitors have demonstrated antitumor efficacy in several preclinical tumor models. Further investigation has revealed these agents to be critically dependent upon the host's immune system, suggesting that the inhibition of TGFβ may overcome the immunosuppressive tumor microenvironment and, ultimately, augment the antitumor immune response. These findings strongly support combining this strategy with other immunotherapeutic approaches for the treatment of metastatic cancer. This review discusses the immunoregulatory and antitumor properties of these pharmacological inhibitors of TGFβ signaling as either independent agents or in combination with various immunotherapeutic strategies, their potential side effects, as well as additional avenues of research that may be necessary for their eventual clinical application.

In vivo characterization of fusion protein comprising of A1 subunit of Shiga toxin and human GM-CSF: Assessment of its immunogenicity and toxicity

BACKGROUND

Most cancer cells become resistant to anti-cancer agents. In the last few years, a new approach for targeted therapy of human cancer has been developed using immunotoxins which comprise both the cell targeting and the cell killing moieties.

METHODS

In the present study, the recombinant Shiga toxin A1 subunit fused to human granulocyte-macrophage colony stimulating factor (A1-GM-CSF), previously produced in E. coli, was further characterized.

RESULTS

The recombinant protein could cause 50% cytotoxicity and induced apoptosis in cells bearing GM-CSF receptors. The non-specific toxicity of the fusion protein was assessed in C57BL/6 and BALB/c mice. No mortality was observed in either group of mice, with different concentration of fusion protein.

CONCLUSION

The lymphocyte proliferation assay, induction of specific IgG response and a mixed (Th1/Th2) response were observed only in BALB/c mice. The mixed response in BALB/c mice (Th1/Th2) could be explained on the basis of the two components of the fusion protein i.e. A1 and GM-CSF.

An update on the therapeutic role of alkylglycerols

Scandinavian folk medicine used shark liver oil for the treatment of cancers and other ailments based on the rarity of tumors in sharks and their ability to resist infections. Shark liver oil is a source of alkylglycerols which have been studied as anti-cancer agents in several clinical trials. Moreover, alkylglycerols have been investigated for the treatment of radiation induced side effects and for their ability to boost the immune system. Several experimental studies have shown the ability of alkylglycerols to open the blood brain barrier to facilitate the access of therapeutic drugs to the central nervous system. This review covers the most important studies of alkylglycerols in both animals and humans.

Isolation and potential immunological characterization of TPSGLVY, a novel bursal septpeptide isolated from the bursa of Fabricius

The bursa of Fabricius is central immune organ unique to birds, and the extract is immunocompetent in stimulating B cell differentiation and enhancing antibody production. However, except for bursin, the active peptides from the bursa of Fabricius are little reported. In the paper, a novel bursal septpeptide (BSP-II) with the amino acids sequence of TPSGLVY was identified and similar to the MGC53864 protein of Gallus gallus. We investigated the effects of BSP-II on the immune response in terms of the antibodies titers (IgG1 and IgG2alpha), the levels of interferon-gamma and interleukin-4 cytokines, spleen cell lymphocyte proliferation, and the T-lymphocyte subtype composition. It was noteworthy that BSP-II potentiates the Th1 and Th2-type immune responses in dose-dependent manner. BSP-II had specific enhancing effects on the hybridoma SP2/0 cell proliferation at two different serum concentrations (20% and 5%), but had no connection with the dose of BSP-II. The antibody secreting level of hybridoma SP2/0 cells rose in 5% and 20% serum when the concentrations of BSP-II increased. Also, BSP-II had effect on the viabilities of tumor cells (Hela and SP2/0). All the results indicated that BSP-II was able to significantly induce various immune responses and involved in the cell viability of different tumor cell lines. Our observations implied that BSP-II might be a novel biological active factor from the bursa of Fabricius with immunomodulatory activities.

[Mutation of EGFR signaling pathway and therapy for metastatic colorectal cancer]

For the patient in whom the Kras gene variation appears, cancer cell grow and continue to multiply even if blocked by EGFR inhibitor. A topping the offered figure effect of cetuximab is not accepted. The addition of cetuximab for treatment of metastatic colorectal cancer with Kras wild-type tumors is effective.

[SOCS1 knockdown sensitize anti-tumor activity of IFN-alpha2a-NGR]

AIM

Search for key molecules to influence the tumor-targeted IFN-alpha2a-NGR anti-tumor sensitivity through signaling pathway study. Try to enhance the antitumor efficacy of IFN-alpha2a-NGR.

METHODS

MTT method was used to determine the growth inhibitory effects of IFN-alpha2a-NGR on A549 and MKN-45 cells. Flow cytometry and Western blot were employed to detect the expression of STAT1, p-STAT1, p53, OAS and SOCS1; SOCS1 gene knock down was carried out by synthesized siRNA.

RESULTS

When stimulated with IFN-alpha2a-NGR, the increased expression of STAT1, p-STAT1, p53, OAS and SOCS1 were observed in A549 cells, but only SOCS1 was notably increased in MKN-45 cells. The proliferation inhibition ability of MKN-45 to IFN-alpha2a-NGR was promoted by SOCS1 knocking down. (the inhibition rate was enhanced from 14.69%+/-1.05% to 36.97%+/-2.05%).

CONCLUSION

This study has further demonstrated that there were no differences on antitumor effects between IFN-alpha2a-NGR and IFN-alpha2a on cell or molecular level. Besides interferon-alpha receptor (IFNAR) which has been demonstrated before, p-STAT1, p53 and SOCS1 were important determinants of tumor resistance to IFNs therapy. The antitumor efficacy of IFN-alpha2a-NGR can be enhanced by RNA interference. These results might be helpful for the further development of IFN-alpha2a-NGR.

[The anti EGFR antibody indication between the Japanese and overseas guidelines]

The revised version of the Japanese colorectal cancer treatment guidelines by the Japanese Society for Cancer of the Colon and Rectum published in July 2009 showed remarkable changes in the field of systemic chemotherapy compared with the 2005 edition. Bevacizumab was approved in 2004 in United States, in 2005 in Europe, and in 2007 in Japan. On the other hand, cetuximab was approved in 2004 in Europe and United States, and in July 2008 in Japan. Besides, capecitabine was approved in September 2009 in Japan for not only adjuvant chemotherapy but also unresectable advanced colorectal cancer. Thus, we had one more treatment option of capecitabine with Oxaliplatin as CapeOx (XELOX). Therefore, most of the standard chemotherapy regimens in Western countries then became available in Japan. There has been no major difference in the drug treatment strategy except for the approval of panitumumab in Europe and the US, but this was not true in Japan. Now KRAS testing is recommended, and the indication for cetuximab is limited to KRAS wild type. Cetuximab can not be administered as the first-line treatment in Japan because KRAS testing is not covered by health insurance. This article deals with the difference in the anti EGFR antibody indication between the Japanese and overseas guidelines.

[Cetuximab for patients with metastatic colorectal cancer-from the result of recent clinical trials]

Cetuximab is a monoclonal antibody that inhibits human epidermal growth factor receptor, and was approved for metastatic advanced colorectal cancer (mCRC) in 2008 in Japan. Evidences confirming the efficacy of cetuximab have been accumulated in western countries. As the first- and second-line therapy, cetuximab plus chemotherapy showed longer survival compared with chemotherapy alone. As a third-line chemotherapy, among various anti-cancer agents for mCRC, only cetuximab could exhibit survival benefits in monotherapy or combination therapy with irinotecan. Recent studies suggest that the status of KRAS mutation is a predictive marker in colorectal cancer patients treated with cetuximab, and these findings lead to personalized cancer treatment.

[Anti-epidermal growth factor receptor monoclonal antibodies induced adverse events]

Cetuximab and panitumumab, both anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (MAb), have demonstrated clinical activity in patients with colorectal cancer. They are well tolerated, but they involve various adverse events that are rare among cytotoxic agents. Typical adverse events associated with anti-EGFR MAbs include infusion reaction, skin toxicity, lung toxicity, and hypomagnesemia. It is necessary to recognize and manage adverse events promptly to continue treatments without drug discontinuation. This report details the adverse events and their management with anti-EGFR MAbs use.

[The current status of development of anti-EGFR antibodies]

The use of cetuximab, a mouse chimeric immunoglobulin G1 monoclonal antibody, is approved as anti-epidermal growth factor receptor(EGFR)therapy for the treatment of metastatic colorectal cancer in Japan. Further, panitumumab, matuzumab, nimotuzumab and zalutumumab which also target EGFR, are currently under clinical development. Cetuximab is the first that has been developed as an anti-EGFR antibody. Approximately 30% of the protein which constructs the mouse chimeric antibodies is from mouse, which yields the possibility that the mouse chimeric antibodies induce host immune-reaction. After cetuximab, the humanized monoclonal antibodies such as matuzumab and nimotuzumab, and fully humanized monoclonal antibodies such as panitumumab and zalutumumab, have been developed. In this article, we will introduce the current status of development of these four anti-EGFR antibodies, by focusing on the individual clinical trials using each anti-EGFR antibody.

[Antibody-dependent cellular cytotoxicity in the immunotherapeutic mechanisms of anti-EGFR monoclonal antibody]

EGFR constitute an attractive target for tumor therapy, because it is a transmembrane receptor tyrosine kinase which is critically involved in tumorigenesis by stimulating cell proliferation and inhibiting apoptosis or other biological functions. The anti-tumor effects of targeted therapy by anti-EGFR monoclonal antibodies are mainly based on direct inhibition of the EGFR signal transduction pathway. In addition, monoclonal antibody has the potential advantage of recruiting immune effect or mechanisms to kill tumor cells. The pre-clinical and clinical data indicated that antibody-dependent cellular cytotoxicity (ADCC) contributes to tumor cell lysis by anti-EGFR monoclonal antibodies. Some polymorphisms in Fc gamma receptor genes have been shown to be a predictive marker for the efficacy of anti-EGFR antibodies. Continued research on the immunotherapeutic mechanisms of monoclonal antibodies will improve the efficacy of antibody-based targeted therapy for cancer.

Establishment of a novel monoclonal antibody against LGR5

LGR5 is an orphan G-protein-coupled receptor (GPCR) that is expressed on the cell surface membrane. LGR5 is reported to be overexpressed in colon, liver, and ovary tumor compared to normal tissue. However, a specific ligand for LGR5 has not yet been determined, and the function is still not clear. An LGR5-specific monoclonal antibody (mAb) is needed as a tool for detection and analysis of LGR5 biological function and cancer therapy. To date, no mAb against LGR5 that retains high affinity and specificity has been reported. Here, we report successful establishment and characterization of a mAb (KM4056) that specifically recognizes the extracellular N-terminal domain of human LGR5, but not LGR4 or LGR6. This mAb has potent complement-dependent cytotoxicity (CDC) activity in vitro and shows strong anti-tumor activity in vivo against xenograft model by transplanting LGR5 expressing CHO transfectants into SCID mice. Thus, KM4056 can be a useful tool for detection of LGR5 positive cells and analysis of LGR5 biological function.

[Gd@C(82)(OH)(22)](n) nanoparticles induce dendritic cell maturation and activate Th1 immune responses

Dendritic cells play a pivotal role in host immune defense, such as elimination of foreign pathogen and inhibition of tumorigenesis. In this paper, we report that [Gd@C(82)(OH)(22)](n) could induce phenotypic maturation of dendritic cells by stimulating DC production of cytokines including IL-12p70, upregulating DC co-stimulatory (CD80, CD83, and CD86) and MHC (HLA-A,B,C and HLA-DR) molecules, and switching DCs from a CCL5-responsive to a CCL19-responsive phenotype. We found that [Gd@C(82)(OH)(22)](n) can induce dendritic cells to become functionally mature as illustrated by their capacity to activate allogeneic T cells. Mice immunized with ovalbumin in the presence of [Gd@C(82)(OH)(22)](n) exhibit enhanced ovalbumin-specific Th1-polarized immune response as evidenced by the predominantly increased production of IFNgamma, IL-1beta, and IL-2. The [Gd@C(82)(OH)(22)](n) nanoparticle is a potent activator of dendritic cells and Th1 immune responses. These new findings also provide a rational understanding of the potent anticancer activities of [Gd@C(82)(OH)(22)](n) nanoparticles reported previously.

Assessment of the pre-clinical immunogenicity of a new VEGF receptor Fc-fusion protein FP3 with ELISA and BIACORE

PURPOSE

A new VEGF receptor fusion protein FP3 was shown to have promising antitumor potency better than Bevacizumab. Characterization of its immune response is essential to the safe and effective administration in clinical trials. In this study, both BIACORE and ELISA assays were employed to assess pre-clinical immunogenicity of FP3 in monkeys.

EXPERIMENTAL DESIGN

Serum samples from 20 rhesus monkeys were analyzed for the generation of anti-FP3 antibody after intravenous administration of three doses of FP3 (n = 6 per group) or buffer control (n = 2). Sera samples were obtained at 2, 4, 6, 8, 10 weeks after the first administration.

RESULTS

It showed BIACORE presented linear correlation with the dilution of anti-FP3 antibody and the results of ELISA. Two weeks after the initial FP3 injection, anti-FP3 antibody was detected in about 20% FP3-treated monkeys. The ratio of positive samples and the titer of antibody increased along with the FP3-treatment time. Six weeks following FP3 injection almost all the samples were anti-FP3 antibody positive. Moreover, the titer of anti-FP3 antibody but not the ratio of positive samples was also enhanced when the dose of FP3 was elevated. Furthermore, the immunoglobulin types and subclasses of anti-FP3 antibody serum components were mainly identified as IgG1 and IgG4, not IgM. Serum antibodies are characterized that they could not block FP3 binding to VEGF and were non-neutralizing.

CONCLUSIONS

Our data implied that proteins with full human sequences may also have the potential to induce immune response in rhesus monkeys, and BIACORE could be an effective approach to detect the immunogenicity of protein therapeutics in clinic.

A general process for the development of peptide-based immunoassays for monoclonal antibodies

Purpose

Monoclonal antibodies (mAb) are an important and growing class of cancer therapeutics, but pharmacokinetic analyses have in many cases been constrained by the lack of standard and robust pharmacologic assays. The goal of this project was to develop a general method for the production of immunoassays that can measure the levels of therapeutic monoclonal antibodies in biologic samples at relevant concentrations.

Methods

Alemtuzumab and rituximab are monoclonal approved for the treatment of B-cell malignancies and were used as a model system. Phage-displayed peptide libraries were screened for peptide sequences recognized by alemtuzumab (anti-CD52) or rituximab (anti-CD20). Synthetic biotinylated peptides were used in enzyme-linked immunosorbent assays (ELISA). Peptides directly synthesized on polymer resin beads were used in an immunofluorescent-based assay.

Results

Peptide mimetope sequences were recovered for both mAb and confirmed by competitive staining and kinetic measurements. A peptide-based ELISA method was developed for each. The assay for rituximab had a limit of detection of 4 μg/ml, and the assay for alemtuzumab had a limit of detection of 1 μg/ml. Antibody-specific staining of peptide conjugated beads could be seen in a dose-dependent manner.

Conclusion

Phage-displayed peptide libraries can be a source of highly specific mimetopes for therapeutic mAb. The biotinylated forms of those peptides are compatible with conventional ELISA methods with sensitivities comparable to other assay methods and sufficient for pharmacological studies of those mAb given at high dose. The process outlined here can be applied to any mAb to enable improved pharmacokinetic analysis during the development and clinical use of this class of therapies.

Electronic supplementary material

The online version of this article (doi:10.1007/s00280-009-1240-1) contains supplementary material, which is available to authorized users.

[Criteria for the effectiveness of interleukin-2 immunotherapy in a spontaneous murine mammary tumor model]

A novel approach is suggested to identify more homogenous subgroups involved in the follow-up of growth of spontaneous mammary tumors in mice (116, history-based analysis). That depends on subclinical period (preneoplastic and non-invasive stages of tumor growth) as well as rate of growth after clinical manifestation. An analysis of tumor growth rate versus survival of experimental and control animals after primary diagnosis and clinical manifestation of tumor showed that following a single peritumoral 2.5 x 10(6) IU IL-2 treatment tumor growth slowed down (n = 29; p < or = 0.05) while survival tended to improve. Originally fast-growing tumors without significant subclinical stage continued to grow but slowly. Females with such tumors survived longer than untreated controls without showing, however, any improvement on that parameter.

TRU-016, a humanized anti-CD37 IgG fusion protein for the potential treatment of B-cell malignancies

TRU-016, under development by Trubion Pharmaceuticals Inc and Facet Biotech Corp, is an intravenously administered anti-CD37 IgG fusion protein for the potential treatment of B-cell malignancies, including chronic lymphocytic leukemia (CLL) and non-Hodgkin's lymphoma (NHL), as well as for autoimmune and inflammatory diseases. TRU-016 was created by humanizing SMIP-016, a mouse/human chimeric protein that demonstrated antitumor activity against lymphoid malignancies in preclinical studies, including in human B-cell tumor mouse xenograft models. In addition, TRU-016 demonstrated synergistic or additive activity in NHL cells in combination with rituximab, rapamycin, doxorubicin and bendamustine. In a phase I/II clinical trial in refractory or relapsed patients with CLL or small lymphocytic lymphoma, TRU-016 was well tolerated, with clinical benefit and a reduced absolute lymphocyte count observed in all cohorts dosed at > 0.1 mg/kg. TRU-016 is a promising therapeutic agent for patients with B-cell lymphoid malignancies, especially patients refractory to standard treatment.

Cancer and pregnancy: parallels in growth, invasion, and immune modulation and implications for cancer therapeutic agents

Many proliferative, invasive, and immune tolerance mechanisms that support normal human pregnancy are also exploited by malignancies to establish a nutrient supply and evade or edit the host immune response. In addition to the shared capacity for invading through normal tissues, both cancer cells and cells of the developing placenta create a microenvironment supportive of both immunologic privilege and angiogenesis. Systemic alterations in immunity are also detectable, particularly with respect to a helper T cell type 2 polarization evident in advanced cancers and midtrimester pregnancy. This review summarizes the similarities between growth and immune privilege in cancer and pregnancy and identifies areas for further investigation. Our PubMed search strategy included combinations of terms such as immune tolerance, pregnancy, cancer, cytokines, angiogenesis, and invasion. We did not place any restrictions on publication dates. The knowledge gained from analyzing similarities and differences between the physiologic state of pregnancy and the pathologic state of cancer could lead to identification of new potential targets for cancer therapeutic agents.

Diabodies: molecular engineering and therapeutic applications

Bispecific antibodies are capable of interacting with two different antigens and when selected properly, can redirect cytotoxic effector cells to tumor cells for effective killing. These antibodies are therefore of great interest in the research and development of cancer treatment. Over the last two decades, many different bispecific antibody-derived molecular formats have been described, among which diabodies represent an important class of engineered molecules that possess tumor-targeting function. Since diabodies were first introduced in the early 1990s, extensive efforts have been made to optimize their physicochemical and key functional properties, as well as to provide in vivo proof of concept of their antitumor efficacy in animal models. With the clinical validation of the T-cell-retargeting mechanism for cancer therapy currently in place, there is renewed interest in this bispecific class of biologic molecules, with additional novel formats being described in recent years. Even with the remaining challenges of the manufacturing yields and drug-like properties, diabodies and their derivatives remain viable therapeutic modalities that warrant further consideration and development.

The ex vivo production of ammonia predicts L-asparaginase biological activity in children with acute lymphoblastic leukemia

Patients with acute lymphoblastic leukemia (ALL), who develop antiasparaginase antibodies without clinical allergic reactions ("silent inactivation") during L: -asparaginase (L: -Asp) treatment, have poor outcomes. Ammonia is produced by hydrolysis of asparagine by L: -Asp. We postulated that plasma ammonia level might reflect the biological activity of L: -Asp. Five children with ALL treated according to the Tokyo Children's Cancer Study Group (TCCSG) protocol were enrolled. Plasma ammonia levels were analyzed immediately and 1 h after incubation at room temperature and "ex vivo ammonia production" was defined as increase in ammonia concentration. Ex vivo ammonia production well correlated with L: -Asp activity (r = 0.882, P < 0.01, n = 23). It always exceeded 170 microg/dL (170-345 microg/dL) in induction therapy. We found 3 patients whose ammonia production was negligible during later phases of therapy. Antiasparaginase antibody was detected and L: -Asp activity decreased in these patients. Ex vivo ammonia production is a surrogate marker of L: -Asp biological activity.

Cutaneous T-Cell Lymphoma: A Paradigm for Biological Therapies

Mycosis Fungoides and Sézary Syndrome are the most common types of cutaneous T-cell lymphomas. There is no current standard of care for Mycosis Fungoides/Sézary Syndrome, with a general tendency to rely on topical interventions for early disease delaying systemic, more toxic therapy until the development of extensive symptoms. Knowledge of the biological characteristics of this disease has allowed for the development of rational interventions and a significant advance in its treatment. Retinoids are active in Mycosis Fungoides/Sézary Syndrome with the newer rexinoids being available in topical and systemic forms. Interferon alpha remains one of the most active therapeutic agents for Mycosis Fungoides/Sézary Syndrome, especially in combination with other agents such as PUVA. The monoclonal antibody alemtuzumab leads to responses in at least half of patients with advanced disease with its side effect profile consisting mainly of immunosupression and infusion reactions. The recombinant IL2-diphteria toxin denileukin diftitox (Ontak) is active in this disease and appears to have a beneficial effect in symptoms relief and quality of life. Extracorporeal photochemotherapy as an immunostimulating intervention seems to be very effective in a subset of patients, but its availability is limited to less than a hundred centers worldwide. Experimental and less studied interventions include autologous and allogeneic peripheral stem cell transplantation, Interleukin-12, the histone-deacetylator depsipeptide and the synthetic deoxynucleotide CpG7909. Cutaneous T-cell lymphoma has served as a paradigm for the development of biological agents. Further knowledge of the signaling pathways in Mycosis Fungoides/Sézary Syndrome will allow for the development of more effective treatment strategies.

Parasitological and immunological diagnosis of Strongyloides stercoralis in patients with gastrointestinal cancer

This study examined the frequency of Strongyloides stercoralis infection in patients with gastrointestinal cancer through parasitological and immunological tests. A total of 77 patients were evaluated, 33 with gastrointestinal cancer and 44 controls with other types of cancers. All the patients were undergoing chemotherapy and 14 (18.2%) were receiving concomitant radiotherapy. For a parasitological diagnosis, we applied the Baermann and Lutz methods. The immunological diagnosis involved the indirect fluorescence antibody test (IFAT) and enzyme linked immunosorbent assay (ELISA) to detect IgG antibodies using Strongyloides ratti antigens. The frequency of positive S. stercoralis in gastrointestinal cancer diagnosed by parasitological methods was 3 cases (9.1%), by serology it was 8 cases (24.2%). In the control group 1 case (2.3%) of S. stercoralis was diagnosed by parasitological methods and 2 cases (4.5%) by immunological tests (p<0.05). Patients with gastrointestinal cancer had a 6.7-fold greater chance of testing positive for S. stercoralis infection. Our data highlight the importance of parasitological and immunological diagnosis for S. stercoralis in patients with gastrointestinal cancer living in endemic areas of strongyloidiasis, since they have a higher risk of becoming infected with S. stercoralis than patients with other types of cancer.

CD20-targeted therapy: a breakthrough in the treatment of non-Hodgkin's lymphoma

Targeting the CD20 antigen on B lymphocytes with the monoclonal antibody rituximab has greatly improved the outcome of patients with B-cell malignancies. Despite the success of rituximab, resistance occurs in about half of the patients, resulting in non-response to treatment or early relapse of the original disease. A better understanding of the mechanism of rituximab resistance has lead to the development of novel, improved anti-CD20 antibodies. This review describes the development of CD20-targeted therapy from its historical background towards the next generation of anti-CD20 monoclonal antibodies and explains new strategies to overcome resistance.

FcgammaRIIIa polymorphisms and cetuximab induced cytotoxicity in squamous cell carcinoma of the head and neck

PURPOSE

The interaction of Fc fragments of antibodies with the Fcgamma receptors is an essential checkpoint in antibody-dependent cellular cytotoxicity (ADCC). Specific polymorphisms at position 158 enhance FcgammaRIIIa affinity for IgG1 and are associated with improved clinical outcome in lymphoma patients treated with IgG1 anti-CD20 antibody. The role of ADCC in the therapeutic effects of the alpha-epidermal growth factor receptor (EGFR) mAb, cetuximab, in patients with squamous cell carcinoma of the head and neck (SCCHN) is poorly defined. We employed three SCCHN cell lines to test two hypotheses: (1) SCCHN is susceptible to cetuximab-mediated ADCC, (2) efficacy of ADCC is associated with polymorphisms at position 158 of FcgammaRIIIa.

EXPERIMENTAL DESIGN

FcgammaRIIIa-158 polymorphisms were determined for healthy donors, and their purified NK cells were used as effector cells against three SCCHN cell lines in ADCC assays. Cytotoxicity levels were compared for each polymorphism class. Proliferation and cell cycle assays were done to examine the direct effects of cetuximab.

RESULTS

Our results indicate that SCCHN is susceptible to cetuximab-mediated ADCC in vitro. NK cytotoxic efficiency correlates with donor 158-polymorphisms in FcgammaRIIIa. Overall cytotoxicity was greatest for individuals having a single V allele when compared to homozygous F/F individuals; the cumulative percent cytotoxicity for each polymorphism among the cell lines was 58.2% V/V, 50.6% V/F, and 26.1% F/F (P < 0.001). Additionally, the presence of a V allele correlated with superior natural cytotoxicity against NK sensitive targets.

CONCLUSION

These data have both prognostic and therapeutic relevance and support the design of a prospective trial to determine the influence of FcgammaRIIIa polymorphisms on the clinical outcome of patients with SCCHN treated with alpha-EGFR mAbs.

Dacetuzumab, a humanized mAb against CD40 for the treatment of hematological malignancies

Dacetuzumab, a humanized mAb targeting the CD40 antigen, is in development by Seattle Genetics Inc and licensee Genentech Inc for the potential treatment of hematological malignancies. The CD40 antigen is a highly expressed cell surface transmembrane protein that is present in normal B-cells. Experiments using blocking antibodies for the CD40 ligand demonstrated that CD40 signaling may play a role in the development and maintenance of B-cell hematological malignancies and some solid tumors. In vitro, dacetuzumab exhibited antitumor activity against several B-cell lymphoma and multiple myeloma (MM) cell lines, and induced direct apoptosis as well as the engagement of effective antibody-dependent cell-mediated cytotoxicity. In vivo, dacetuzumab demonstrated enhanced antitumor efficacy in combination with other mAbs and chemotherapeutic agents; many of these combinations are now being tested clinically. Early clinical trials have evaluated the pharmacokinetics, safety and efficacy of dacetuzumab monotherapy in patients with relapsed/refractory B-cell lymphomas or MM. Targeting CD40 with dacetuzumab resulted in modest antitumor activity in B-cell lymphomas and, to a lesser extent, in MM. In particular, patients with diffuse large B-cell lymphoma responded well to dacetuzumab; the drug is being pursued for this indication in phase II trials.

GA-101, a third-generation, humanized and glyco-engineered anti-CD20 mAb for the treatment of B-cell lymphoid malignancies

Glycart Biotechnology AG, Genentech Inc, F Hoffmann-La Roche Ltd, Biogen Idec Inc and Chugai Pharmaceutical Co Ltd are developing GA-101, a third-generation, humanized and glyco-engineered anti-CD20 IgG1 mAb, for the potential treatment of B-cell malignancies. Compared with classic type I CD20 antibodies (eg, rituximab), GA-101 binds with high affinity to the CD20 type II epitope, resulting in the induction of antibody-dependent cytotoxicity that is 5- to 100-fold greater than observed upon treatment with rituximab. GA-101 also exhibits superior direct cell killing properties than rituximab. In preclinical studies, GA-101 was significantly more potent and effective in depleting B-cells than rituximab, and induced dose-dependent antitumor activity, complete tumor regression and improved long-term survival in xenograft mouse models of B-cell malignancy. In a phase I/II clinical trial, GA-101 had a similar safety profile to rituximab, and exhibited promising efficacy in patients with relapsed/refractory CD20-positive lymphoid malignancies. At the time of publication, phase I/II trials for GA-101 were ongoing in B-cell malignancies. Based on preclinical and preliminary clinical data, GA-101 appears to be a promising therapeutic agent for CD20-positive B-cell lymphoid malignances, including non-Hodgkin lymphomas and chronic lymphocytic leukemia.

[Second-line chemotherapy for colorectal cancer]

For the current metastatic colorectal cancer, FOLFIRI or FOLFOX is chosen as first-line chemotherapy. Second-line irinotecan-based chemotherapy is commonly used after first-line oxaliplatin-based chemotherapy. Of course, FOLFOX becomes the second-line if FOLFIRI becomes primary therapy. It is important that these regimens combine molecular targetting agents such as Bevacizumab or Cetuximab. The addition of these new agents offers a chance to further enhance the activity of conventional chemotherapy.

[Second-line treatment using novel chemotherapeutic and biologic agents]

The goal of therapy for recurrent cancer is to delay progression, relieve symptoms, and improve QOL. Cytotoxic agents combined with carboplatin for sensitive disease(TFIB6 months), and cytotoxic agents without cross-resistance to taxane/platinum against resistant diseases are required. There is a limit to improvement in efficacy by using cytotoxic agents, and a promising biological agent is expected to emerge while phase II studies of various biological agents continue. Regarding molecular-target drugs, only bevacizumab is confirmed to be effective at present, so it is used in monotherapy or combination therapy with anticancer drugs. In the GOG started a RCT of bevacizumab or placebo that was combined with TC regimen. Also in patients with chemo-sensitive disease, a RCT of TC regimen combined with or without bevacizumab started. In addition, EORTC and ICON trials of cediranib and erlotinib combined with platinum-based regimen are on-going.

Ipilimumab: controversies in its development, utility and autoimmune adverse events

A promising new class of anti-cancer drugs includes antibodies that mediate immune regulatory effects. It has become very clear over the last decade that different types of immune cells and different pathways serve to suppress anti-cancer immunity, particularly in the microenvironment of the tumor. The first examples of immune modulating antibodies are those directed against cytotoxic T lymphocyte antigen-4 (CTLA-4), a molecule present on activated T cells. Human antibodies that abrogate the function of CTLA-4 have been tested in the clinic and found to have clinical activity against melanoma. In this review, we discuss some of the controversies surrounding the potential clinical utility of one of those antibodies, ipilimumab, formerly MDX-010, from Medarex and Bristol Myers Squibb. The optimal dose and schedule of ipilimumab was derived in multiple clinical trials whose latest results are described below. Favorable survival in patients with stage IV melanoma were observed that appear to be associated with unique side effects of the drug called "immune-related adverse events". The management of these side effects is described, and the unusual kinetics of anti-tumor response with ipilimumab as well as a newly proposed schema for assessing anti-tumor responses in patients receiving biologic compounds like ipilimumab, which may supercede RECIST or WHO criteria, are addressed.

[Chemotherapy for breast cancer refractory to anthracycline, taxane or trastuzumab]

Anthracycline, taxane or trastuzumab play a central role in systemic chemotherapy for breast cancer. The standard of subsequent treatment is capecitabine, S-1, vinorelbine, irinotecan or gemcitabine. Ixabepilone or nanoparticle paclitaxel is effective for taxane-resistant breast cancer. Lapatinib proves effective for trastuzumab-resistant HER2-overexpressing breast cancer and also for brain metastasis. Trastuzumab-DM1, pertuzumab and neratinib are promising drugs. In terms of antiangiogenic agents, bevacizumab in combination with taxane demonstrates efficacy. Axitinib, sunitinib or pazopanib is under investigation. It is necessary to study the best manner of sequence and combination in these drugs.

Phase I/II study of humanized anti-CD33 antibody conjugated with calicheamicin, gemtuzumab ozogamicin, in relapsed or refractory acute myeloid leukemia: final results of Japanese multicenter cooperative study

The primary objective of this study was to investigate the tolerability, efficacy and pharmacokinetic profile of gemtuzumab ozogamicin (GO) in patients with relapsed and/or refractory CD33-positive acute myeloid leukemia (AML). Patients received 2-h infusions of GO twice with an interval of approximately 14 days. Tolerability was assessed using the National Cancer Institute Common Toxicity Criteria Version 2.0. Samples for pharmacokinetics were taken on day 1 and day 8 of the first treatment cycle. The dose was increased stepwise and, in each cohort, patients were treated at the same dose. Forty patients, median age 58 years (range 28-68) were treated; 20 and 20 patients were enrolled to the phase I and II parts, respectively. In the phase I part, dose-limiting toxicities (DLTs) were hepatotoxicities, and the recommended dose was established as 9 mg/m2 given as two intravenous infusions separated by approximately 14 days. The pharmacokinetic study revealed that Cmax and AUC were equivalent to those of non-Japanese patients. In the phase II part, complete remission was observed in 5 patients, and one patient had complete remission without platelet recovery. Four of these 6 in remission and one in the phase I are long-term survivors (alive for at least 44 months). GO is safe and effective as a single agent among Japanese CD33-positive AML patients. Remission lasted longer in a subset of patients than in non-Japanese patients in earlier studies. Further studies of this agent are warranted to establish standard therapy.

[Molecular targeted therapy in colorectal cancer and its resistance]

The prognosis of advanced colorectal cancer has been improved by introduction of molecular targeting agents, such as bevacizumab and cetuximab. Several clinical trials revealed a median survival time of more than 2 years. However, the main purpose of chemotherapy for advanced colorectal cancer has not been cure but prolongation of life to date. One explanation of the difficulty of cure is the inherent and/or acquired resistance to chemotherapeutic agents and molecular targeting agents. A better understanding of the mechanisms of inherent resistance will make it possible to identify predictive markers of responder or non-responder to select the optimal patients for a certain drug. Additionally, knowledge of the acquired mechanism will provide for the rational development of therapies that circumvent or overcome resistance. Although the mechanisms of the resistance of molecular targeting agents for colorectal cancer are still unclear, the inherent resistance to cetuximab or panitumumab by why of expression of KRAS mutation is the first breakthrough in this field. Further basic research and biomarker analysis of large clinical study are necessary to clarify the resistance to molecular targeting agents.

Development of an enrofloxacin immunosensor based on label-free electrochemical impedance spectroscopy

Enrofloxacin is the most widespread antibiotic in the fluoroquinolone family. As such, the development of a rapid and sensitive method for the determination of trace amounts of enrofloxacin is an important issue in the health field. The interaction of the enrofloxacin antigen to a specific antibody (Ab) immobilized on an 11-mercapto-undecanoic acid-coated gold electrode was quantified by electrochemical impedance spectroscopy. Two equivalent circuits were separately used to interpret the obtained impedance spectra. These circuits included one resistor in series with one parallel circuit comprised of a resistor and a capacitor (1R//C), and one resistor in series with two parallel RC circuits (2R//C). The results indicate that the antigen-antibody reaction analyzed using the 1R//C circuit provided a more sensitive resistance increment against the enrofloxacin concentration than that of the 2R//C circuit. However, the 2R//C circuit provided a better fitting for impedance spectra, and therefore supplies more detailed results of the enrofloxacin-antibody interaction, causing the increase of electron transfer resistance selectively to the modified layer, and not the electrical double layer. The antibody-modified electrode allowed for analysis of the dynamic linear range of 1-1000 ng/ml enrofloxacin with a detection limit of 1 ng/ml. The reagentless and label-free impedimetric immunosensors provide a simple and sensitive detection method for the specific determination of enrofloxacin.

Bispecific antibodies for cancer therapy

In recent decades, mAbs have emerged as therapeutics. Nine mAbs have been approved for cancer therapy. However, the efficiency of mAbs is far from optimal, and antibody engineering is actively used to improve the molecules. Because of their ability to simultaneously bind two different antigens, bispecific antibodies are unique, and their wide potential as targeting reagents has been demonstrated over the years. However their use as therapeutics has been restrained by manufacturing challenges. Several new recombinant formats have changed the situation. Innovative molecules have led to impressive preclinical and clinical results, and hold great promise. This review presents an overview of the most promising candidates.

From the diet to the nucleus: vitamin A and TGF-beta join efforts at the mucosal interface of the intestine

The vitamin A metabolites, including retinoic acid (RA), form ligands for retinoic acid-related nuclear receptors and together they play pleiotropic roles in various biological processes. Recently, we described that RA also functions as a key modulator of transforming growth factor-beta (TGF-beta)-driven immune deviation, capable of suppressing the differentiation of interleukin-17 secreting T helper cells (T(H)17) and conversely promoting the generation of Foxp3(+) T regulatory (Treg) cells. This review will focus on the role of RA in the reciprocal TGF-beta-driven differentiation of T(H)17 and Treg and on the importance of such regulatory mechanism to control a functional immune system, in particular at the mucosal interface of the intestine.

Inhaled IL-2 induces systemic immunomodulation in patients with renal cell carcinoma and lung metastasis

The peripheral blood lymphocytes of eight patients with metastatic renal cell carcinoma, and of eight healthy volunteers were analyzed by four-color flow cytometry to characterize the immunophenotypic alterations manifested, determine the prevalence of lymphocyte apoptosis, and detect evidence of the systemic effect of inhaled IL-2. The T, B and NK lymphocytes of untreated patients were found to have undergone profound changes characterized by an increase in susceptibility to both spontaneous and mitogen-induced ex vivo apoptosis, a modified distribution of the main lymphocyte populations in the peripheral blood, and alterations in activation status. An increase in the proportion of regulatory T cells was also seen in these patients. Treatment with inhaled IL-2, however, normalized the rate of apoptosis in all the lymphocyte subpopulations studied, as well as their distribution and activation status. These findings demonstrate that inhaled IL-2 has systemic immunomodulatory effects.

Regulation of CD8(+) T cell functions by RARgamma

Retinoic acid plays a key role in the development and function of the immune system; however, the contribution of each of the three retinoic acid receptors (RARs) to the T cell immune response is not yet well understood. Of these receptors, both RARalpha and RARgamma are expressed in T lymphocytes. While possible functional redundancy thus complicates understanding of the role of each receptor in T cells, emerging data suggest that RARalpha and RARgamma function differently in thymocyte development and that RARgamma is required for both primary and secondary CD8(+) T cell immune responses.

Drug-induced immune hemolytic anemia

Drug-induced immune hemolytic anemia (DIIHA) is rare, and a specialized laboratory is often required to provide the optimal serological tests to confirm the diagnosis. The most common drugs associated with DIIHA and the hypotheses for the mechanisms thought to be involved have changed during the last few decades. The drugs most frequently associated with DIIHA at this time are cefotetan, ceftriaxone, and piperacillin. DIIHA is attributed most commonly to drug-dependent antibodies that can only be detected in the presence of drug (eg, cephalosporin antibodies). DIIHA can also be associated with drug-independent antibodies; such antibodies do not need drug to be present to obtain in vitro reactions (eg, fludarabine). In these latter cases, the drug affects the immune system, causing production of red cell (RBC) autoantibodies; the clinical and laboratory findings are identical to autoimmune hemolytic anemia (AIHA), other than the remission associated with discontinuing the drug. Some of the mechanisms involved in DIIHA are controversial. The most acceptable one involves drugs, like penicillin, that covalently bind to proteins (eg, RBC membrane proteins); RBCs become coated with drug in vivo and, a drug antibody (usually IgG) attaches to the drug-coated RBCs that are subsequently cleared by macrophages. The most controversial is the so-called immune complex mechanism, which has been revised to suggest that most drugs are capable of binding to RBC membrane proteins, but not covalently like penicillins. The combined membrane plus drug can create an immunogen; the antibodies formed can be IgM or IgG and often activate complement, leading to acute intravascular lysis and sometimes renal failure; fatalities are more common in this group. It is still unknown why and how some drugs induce RBC autoantibodies, sometimes causing AIHA.

[A case of therapy for bevacizumab-induced hypertension]

The patient was a 73-year-old female with sigmoid colon cancer, who underwent resection of sigmoid colon cancer and liver metastasis. She was treated with 5-fluorouracil and levofolinate calcium(sLV5FU2)plus bevacizumab(BV) for advanced colorectal cancer. She was treated with angiotensin II receptor blocker(ARB)because hersystolic blood pressure was 200 mmHg and her diastolic blood pressure 100 mmHg after five courses of BV therapy. As a result, her blood pressure was controlled. It was possible to administer BV. Therefore, ARB may be the preferred antihypertensive agent in the management of BV-induced hypertension.

[Construction and expression of anti-tumor necrosis factor related apoptosis-inducing ligand receptor death receptor 5 chimeric antibody in eukaryotic cells]

OBJECTIVE

To construct the human/mouse chimeric antibody of a functional anti-death receptor 5 (DR5) antibody. Methods The viable region of light chain (VL) and viable region of heavy chain (VH) genes of anti-DR5 antibody were amplified and cloned into the light- and heavy-chain expression vectors respectively, then the recombinant plasmids were co-transfected into dihydrofolate reductase(-) Chinese hamster ovary cell (CHO-dhfr(-)) for expression. The positive clone was screened by the two selective genes (neo and dhfr). The humanization and specificity of chimeric antibody was identified by ELISA and Western blotting, and the tumoricidal activity of the expressed chimeric antibody was detected by tetrazolium salt phenazine methosulfate assay.

RESULTS

The expression vectors stably expressed chimeric antibody in CHO-dhfr(-). In the cell supernatant of the F4' clone, the human IgG heavy constant region and light constant region were identified. Moreover, the secreted chimeric antibody retained the binding capacity to the antigen (DR5) and decreased the cell viability of Jurkat and HCT116 cells to 73.15% and 77.30% in vitro respectively.

CONCLUSION

The human/mouse anti-DR5 chimeric antibody has been successfully expressed in eukaryotic cells and shows tumoricidal activity, which establishes a foundation for the future research of humanized antibody medicine.

Bioactivity, pharmacokinetics, and immunogenicity assays in preclinical and clinical trials for recombinant human endostatin

AIM

To determine the in vitro and in vivo bioactivity of recombinant human endostatin (rhEndostatin) and to analyze its pharmacokinetics and immunogenicity in rhesus monkeys and patients.

METHODS

The physical chemical characteristics of rhEndostatin were detected according to Pharmacopoeia of the People's Republic of China (2005 edition, part III). Its in vitro and in vivo bioactivities were assayed via proliferation-inhibition on human umbilical vein endothelial cells and their inhibitory effect on tumor-bearing mice models. Serum concentrations of rhEndostatin in monkeys and patients were determined by an enzyme immunoassay method.

RESULTS

The corresponding specific in vitro activities of rhEndostatin obtained from the cell counting method, 3-(4,5-dimethylthiazol-2- yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and lactate dehydrogenase assay, respectively, were 6.4 x 10(7), 6.7 x 10(7), and 3.8 x 10(8) U/mg, and the in vivo antitumoral potency was 4.04 x 10(7) U/mg. In rhesus monkeys, there were no gender differences in all pharmacokinetic parameters. Serum anti-rhEndostatin immunoglobulin (Ig)G antibodies were generated quickly after intravenous (iv) administration and decreased rapidly when therapy was stopped. In phase I clinical trials, linearity in the pharmacokinetics of rhEndostatin was indicated by dose-proportionate increases in the area under the curve and the maximum serum concentration. Serum rhEndostatin reached a steady-state level after 7 d of successive administration with the average concentration at a steady state of 272.44+/-91.98 ng/mL. Neither IgG nor IgM antibodies against rhEndostatin were observed in patients.

CONCLUSION

RhEndostatin exhibited a definite proliferation- inhibition effect on HUVEC, and significant antitumoral activity in mice. The immunoreactivity of rhesus monkeys to rhEndostatin is common, and rhEndostatin showed no immunogenicity in patients in this trial. The results provide a basis for further clinical trials.

[Infusion reactions]

Monoclonal antibody treatment, which is one of the most promising molecular targeting cancer therapies, has recently become indispensable for the treatment of cancer due to its effectiveness and fewer side effects. Infusion reactions, which are similar to hypersensitivity or allergic reactions, are the generic term for the acute characteristic harmful reactions commonly associated with monoclonal antibody treatment. Those typically occur within the first 2 hours of the first infusion and are generally mild-to-moderate reactions which can be managed by either temporary interruption of infusion or administration of supportive care including corticosteroids, oxygen, or intravenous fluids. However, there are sometimes severe or life-threatening reactions, thus indicating the importance of closely observing the patient following the monoclonal antibody treatment. It is quite important that the entire medical staff understands the practical information regarding the timing and prevention or management of infusion reactions. In addition, it is also necessary to establish a system for prompt management of infusion reactions. Furthermore, sufficient information must be provided to the patient regarding infusion reactions.