A Soybean Resistant Protein-Containing Diet Increased the Production of Reg3γ Through the Regulation of the Gut Microbiota and Enhanced the Intestinal Barrier Function in Mice

The maintenance of intestinal homeostasis is necessary for a good quality of life, and strengthening of the intestinal barrier function is thus an important issue. Therefore, we focused on soybean resistant protein (SRP) derived from kori-tofu (freeze-dried tofu), which is a traditional Japanese food, as a functional food component. In this study, to investigate the effect of SRP on the intestinal barrier function and intestinal microbiota, we conducted an SRP free intake experiment in mice. Results showed that ingestion of SRP decreased the serum level of lipopolysaccharide-binding protein and induced the expression of Reg3γ, thereby improving the intestinal barrier function. In addition, SRP intake induced changes in the cecal microbiota, as observed by changes in β-diversity. In particular, in the microbiota, the up-regulation of functional gene pathways related to the bacterial invasion of epithelial cells (ko05100) was observed, suggesting that Reg3γ expression was induced by the direct stimulation of epithelial cells. The results of this study suggest that SRP is a functional food component that may contribute to the maintenance of intestinal homeostasis.

Abstract CT111: Results of a phase 1 dose escalation study of ERY974, an anti-glypican 3 (GPC3)/CD3 bispecific antibody, in patients with advanced solid tumors

Background: ERY974, a bispecific T cell-redirecting antibody, redirects T cells to tumor cells by engaging the CD3 antigen on T cells and the glypican 3 (GPC3) antigen selectively expressed on tumors. ERY974 demonstrates T cell-dependent cellular cytotoxicity in vitro and transient cytokine elevations in preclinical toxicology studies (Ishiguro et al. 2017). The primary objective of this dose escalation (DE) study was to determine ERY974's maximum tolerated dose in patients with locally advanced or metastatic solid tumors expressing GPC3. Methods: The study included adult patients with advanced or metastatic solid tumors not amenable to standard therapy, histologically confirmed, with measurable disease and a life expectancy ≥ 3 months, including patients with ≤ 1cm and ≤ 1 brain metastasis. Patients with interstitial lung disease, or acute/active chronic infection were excluded. ERY974 was administered IV and dosed weekly. DE was initiated with an accelerated titration design of single patient cohorts followed by three patient cohorts. To mitigate for the toxicity of cytokine release syndrome (CRS), steroid prophylaxis and a flexible study design was implemented which included a two-step intra-patient escalation (regimen A), and a three-step intra-patient escalation (regimen B). Results: 29 patients were enrolled in dose levels ranging from 0.003 μg/kg to 0.81 μg/kg. Treatment-related adverse events that occurred in greater than 20% of patients included CRS and pyrexia. Dose level 0.81 μg/kg (regimen A) was confirmed not tolerable due to DLTs of Grade 3 CRS and Grade 2 CRS in two out of three patients (assessed according to Lee, et al. 2014). The Grade 3 CRS was associated with Grade 3 transaminitis and a Grade 3 elevation of bilirubin. Both CRS events led to dose delay and dose reduction. Increases in IL-6, IL-8 and IL-10 were observed in patients with the CRS. The severity and frequency of CRS in regimen B were similar to those observed in regimen A at the same dose level. One partial response (per modified RECIST criteria) was observed in a patient with esophageal cancer treated with 0.54 μg/kg (regimen B) and having 40% of the tumor tissue staining positive for GPC3 via immunohistochemistry. Stable disease lasting 3 months or longer was observed in four patients. Conclusions: The observed responses and CRS side effects are markers of ERY974 biologic activity. At doses below 0.81 μg/kg (regimen A), ERY974 was generally well tolerated with a manageable toxicity profile, including ERY-induced CRS which was manageable with steroid administration and anti-IL6R therapy. Further research is required to determine if combined prophylactic anti-IL6R and steroid therapy is a more effective strategy for managing CRS. References: 1. Ishiguro, Takahiro, et al. Science translational medicine, 2017, 9.410: eaal4291. 2. Lee, Daniel W., et al. Blood, 2014, 124.2: 188-195.

Citation Format: Howard Safran, Mihaela Druta, Michael Morse, Filipa Lynce, Sofya Pintova, Khaldoun Almhanna, Daniel Weiss, Athos Gianella-Borradori, Yoshitaka Ogita, Roland Morley, Mikiko Nakamura, Junnosuke Matsushima, Takahiro Ishiguro. Results of a phase 1 dose escalation study of ERY974, an anti-glypican 3 (GPC3)/CD3 bispecific antibody, in patients with advanced solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr CT111.

Preclinical PET imaging of bispecific antibody ERY974 targeting CD3 and glypican 3 reveals that tumor uptake correlates to T cell infiltrate

BACKGROUND

Bispecific antibodies redirecting T cells to the tumor obtain increasing interest as potential cancer immunotherapy. ERY974, a full-length bispecific antibody targeting CD3ε on T cells and glypican 3 (GPC3) on tumors, has been in clinical development However, information on the influence of T cells on biodistribution of bispecific antibodies, like ERY974, is scarce. Here, we report the biodistribution and tumor targeting of zirconium-89 (⁸⁹Zr) labeled ERY974 in mouse models using immuno-positron emission tomography (PET) imaging.

METHODS

To study both the role of GPC3 and CD3 on the biodistribution of [⁸⁹Zr]Zr-N-suc-Df-ERY974, ⁸⁹Zr-labeled control antibodies targeting CD3 and non-mammalian protein keyhole limpet hemocyanin (KLH) or KLH only were used. GPC3 dependent tumor targeting of [⁸⁹Zr]Zr-N-suc-Df-ERY974 was tested in xenograft models with different levels of GPC3 expression. In addition, CD3 influence on biodistribution of [⁸⁹Zr]Zr-N-suc-Df-ERY974 was evaluated by comparing biodistribution between tumor-bearing immunodeficient mice and mice reconstituted with human immune cells using microPET imaging and ex vivo biodistribution. Ex vivo autoradiography was used to study deep tissue distribution.

RESULTS

In tumor-bearing immunodeficient mice, [⁸⁹Zr]Zr-N-suc-Df-ERY974 tumor uptake was GPC3 dependent and specific over [⁸⁹Zr]Zr-N-suc-Df-KLH/CD3 and [⁸⁹Zr]Zr-N-suc-Df-KLH/KLH. In mice engrafted with human immune cells, [⁸⁹Zr]Zr-N-suc-Df-ERY974 specific tumor uptake was higher than in immunodeficient mice. Ex vivo autoradiography demonstrated a preferential distribution of [⁸⁹Zr]Zr-N-suc-Df-ERY974 to T cell rich tumor tissue. Next to tumor, highest specific [⁸⁹Zr]Zr-N-suc-Df-ERY974 uptake was observed in spleen and lymph nodes.

CONCLUSION

^[89Zr]Zr-N-suc-Df-ERY974 can potentially be used to study ERY974 biodistribution in patients to support drug development.

Exploitation of Elevated Extracellular ATP to Specifically Direct Antibody to Tumor Microenvironment

The extracellular adenosine triphosphate (ATP) concentration is highly elevated in the tumor microenvironment (TME) and remains tightly regulated in normal tissues. Using phage display technology, we establish a method to identify an antibody that can bind to an antigen only in the presence of ATP. Crystallography analysis reveals that ATP bound in between the antibody-antigen interface serves as a switch for antigen binding. In a transgenic mouse model overexpressing the antigen systemically, the ATP switch antibody binds to the antigen in tumors with minimal binding in normal tissues and plasma and inhibits tumor growth. Thus, we demonstrate that elevated extracellular ATP concentration can be exploited to specifically target the TME, giving therapeutic antibodies the ability to overcome on-target off-tumor toxicity.

Cauda Equina and Filum Terminale Arteriovenous Fistulas: Anatomic and Radiographic Features

Intradural AVF below the conus medullaris may develop either on the filum terminale or the cauda equina (lumbosacral and coccygeal radicular nerves). Although not a few filum terminale AVFs are found in the literature, only 3 detailed cauda equina AVFs have been reported. Here, we analyze the angiographic and MR imaging findings of our cauda equina and filum terminale AVF cases, supplemented with literature research to characterize the radiologic features of the 2 entities. On angiography, filum terminale AVFs were invariably supplied by the extension of the anterior spinal artery accompanied by a closely paralleling filum terminale vein. Cauda equina AVFs were fed by either a radicular or a spinal artery or both arteries, often with a characteristic wavy radicular-perimedullary draining vein. On thin-section axial MR imaging, the filum terminale AVF draining vein joined the spinal cord at the conus medullaris apex, but that of the cauda equina AVF joined above the conus medullaris apex.

Abstract 2378: Differential exhaustion on cytokine release (DECREASE) by ERY974, a novel T-cell-redirecting antibody targeting glypican-3: A new type of T-cell exhaustion

Background: T cell-redirecting antibody (TRAB), which bispecifically binds to CD3 and tumor antigen, is a key player in next-generation cancer immunotherapy (CIT). Because TRAB can redirect T cells regardless of their TCR specificity, it is expected to be efficacious in immune checkpoint inhibitor-resistant tumors. The CD19-targeting bispecific T cell engager, blinatumomab, has been used for the treatment of blood cancers, and CEA-TCB and IMCgp100 have shown promising clinical efficacy in solid tumors as well. ERY974 is another promising TRAB targeting glypican-3 (GPC3) and a phase 1 study is in progress (Ishiguro et al., Sci Transl Med 2017). On the other hand, cytokine release syndrome (CRS) has been recognized as a common side effect of TRAB. Thus, mitigation of CRS is an urgent issue. Intra-patient step-up dosing regimens have been incorporated in clinical trials to reduce cytokine release, but the mechanism behind this phenomenon remains elusive. In this study, we pre-clinically explored the phenomenon and its mechanism by using ERY974.

Method & Results: GPC3-expressing human cancer cells were incubated with human PBMCs and ERY974. The incubated PBMCs were harvested and mixed with newly prepared GPC3-expressing cancer cells and higher doses of ERY974. The pre-treated PBMCs showed reduced cytokine production compared to that without pre-treatment, while maintaining the same level of T cell-dependent cellular cytotoxicity (TDCC). Comprehensive gene expression analysis of the pre-treated PBMCs was also conducted. A murine cancer cell line expressing human GPC3 was established and implanted into immune competent mice. A mouse surrogate version of ERY974 (mERY974) was first administered at a low dose expected to elicit weak anti-tumor activity, and mice were then treated with a higher dose of mERY974. Anti-tumor activity was similar regardless of the pre-treatment, but plasma cytokine levels were shown to be reduced in the pre-treated mice upon administration of the higher dose of mERY974.

Conclusion: Cytokine production following the high-dose ERY974 treatment was mitigated by the low-dose pre-treatment in vitro and in vivo. Cytotoxic activity did not decrease in this setting, thus demonstrating that the pre-treatment selectively suppressed only cytokine production. It is well known that repeated stimulation of TCR leads to T-cell exhaustion. The phenomenon we observed here can also be characterized as a sort of exhaustion, but is quite unconventional. Thus, we propose a new type of exhaustion and suggest calling it ‘Differential exhaustion on cytokine release (DECREASE)’. Management of CRS is critical for the clinical use of TRAB. A detailed analysis of the mechanism of DECREASE currently in progress, is expected to contribute to the development of desired dosing regimens for this new type of CIT agent.

Citation Format: Mayumi Hoshino, Yuji Sano, Yasuko Kinoshita, Yumiko Azuma, Toshiaki Tsunenari, Yoko Kayukawa, Mizuho Noguchi, Takahiro Ishiguro, Shohei Kishishita, Noriaki Sawada, Mika Endo, Junichi Nezu. Differential exhaustion on cytokine release (DECREASE) by ERY974, a novel T-cell-redirecting antibody targeting glypican-3: A new type of T-cell exhaustion [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2378.

Indocyanine green fluorescence angiography of the reconstructed gastric tube during esophagectomy: efficacy of the 90-second rule

By examining the reconstructed gastric tube during esophagectomy using indocyanine green fluorescence (ICG) angiography, we have established a '90-second rule' to confirm good blood perfusion at the anastomosis site. We examined the surgical outcome (rate of anastomotic leakage) of 70 consecutive patients who underwent esophagectomy with gastric tube reconstruction using ICG fluorescence angiography. All of the anastomoses were made in the area where less than 90 seconds was needed for enhancement using ICG fluorescence angiography (i.e. within the 90-second rule). In 18 cases for which the time until enhancement of the gastric tube tip exceeded 60 seconds, the anastomosis site was decided by reference to the ICG fluorescence angiogram, and the hypoperfused area was excised, and this significantly shortened the median time until enhancement of the gastric tube tip from 95.5 (60.0-204.0) seconds to 41.0 (9.0-77.0) seconds (P < 0.001). In three cases, the anastomosis was made at the site where more than 60 seconds was needed for ICG enhancement. In one case where ICG enhancement had taken 77 seconds, minor anastomotic leakage occurred. The overall rate of anastomotic leakage in this series was 1.4%. Blood flow in the reconstructed gastric tube is sufficient if the anastomosis is made in the area where ICG fluorescence angiography demonstrates enhancement within 60 seconds. Gastric tube necrosis can be avoided if the area showing an enhancement time exceeding 90 seconds is excised. The 90-second rule is a safe and effective method for deciding the site of anastomosis.

Engineering a bispecific antibody with a common light chain: Identification and optimization of an anti-CD3 epsilon and anti-GPC3 bispecific antibody, ERY974

The antibody drug market is rapidly expanding, and various antibody engineering technologies are being developed to create antibodies that can provide better benefit to patients. Although bispecific antibody drugs have been researched for more than 30 years, currently only a limited number of bispecific antibodies have achieved regulatory approval. Of the few successful examples of industrially manufacturing a bispecific antibody, the "common light chain format" is an elegant technology that simplifies the purification of a whole IgG-type bispecific antibody. Using this IgG format, the bispecific function can be introduced while maintaining the natural molecular shape of the antibody. In this article, we will first introduce the outline, prospects, and limitations of the common light chain format. Then, we will describe the identification and optimization process for ERY974, an anti-glypican-3 × anti-CD3ε T cell-redirecting bispecific antibody with a common light chain. This format includes one of Chugai's proprietary technologies, termed ART-Ig technology, which consists of a method to identify a common light chain, isoelectric point (pI) engineering to purify the desired bispecific IgG antibody from byproducts, and Fc heterodimerization by an electrostatic steering effect. Furthermore, we describe some tips for de-risking the antibody when engineering a T cell redirecting antibody.

Abstract 3028: PET imaging with the bispecific 89Zr-antibody ERY974 targeting CD3 and glypican 3 in tumor-bearing mouse models

BACKGROUND: ERY974, a modified monoclonal IgG4 bispecific antibody directed against human CD3 on T cells and glypican 3 (GPC3) on tumor cell, is currently in phase I clinical trial. The oncofetal protein GPC3 is overexpressed in several tumor types. Radiolabeling ERY974 with positron emission tomography (PET) isotope zirconium-89 (89Zr) enables non-invasive molecular imaging of tumor targeting and whole-body distribution. We aimed to evaluate 89Zr-ERY974 tumor targeting and effect of T cells on tumor uptake in mouse models, including a humanized mouse model.

METHODS: ERY974 and two control molecules namely bispecific CD3xkeyhole limpet hemocyanin (KLH) and KLHxKLH antibodies were radiolabeled with 89Zr. Studies were performed in immunodeficient NOD/Shi-SCID/IL-2Rgnull (NOG) as well as human CD34+ hematopoietic stem cell engrafted NOG mice (huNOG), all subcutaneously inoculated with GPC3 overexpressing human hepatocellular carcinoma HepG2 cells. Mice received 10 µg 89Zr-ERY974, 89Zr-CD3xKLH or 89Zr-KLHxKLH intravenously, with subsequent µPET scanning at 24, 72, 120 and 168 h followed by ex vivo biodistribution. Organs of interest were quantified on µPET scans as mean standardized uptake value (SUVmean) and with ex vivo biodistribution as % injected dose/gram of tissue (%ID/g). Tumor, spleen and lymph nodes were analyzed with autoradiography and immunohistochemical CD3 staining.

RESULTS: µPET imaging revealed increased tumor-to-blood ratio (TBR) of 89Zr-ERY974 in NOG over time with maximal TBR of 2.2±0.3 at 168 h post tracer injection (pi). At 168 h, tumor uptake was specific as 89Zr-CD3xKLH and 89Zr-KLHxKLH showed a TBR of only 0.6±0.2 and 0.8±0.3, respectively. In huNOG mice human CD3+ T cells were present in tumor, spleen and lymph nodes. In huNOG mice tumor uptake of 89Zr-ERY974 was higher than in NOG mice as measured on µPET scans (SUVmean at 168 h pi 6.9±2.6 vs 2.9±0.2; P&lt;0.01) and with ex vivo biodistribution (60.9±26.2 %ID/g vs 16.7±2.3 %ID/g; P&lt;0.001), whereas 89Zr-CD3xKLH tumor uptake in both mouse models was lower (P&lt;0.05) but were similar in these mouse models. Autoradiography 168 h following 89Zr-ERY974 administration to huNOG mice showed 89Zr in extensive T cell infiltrate areas in the tumors of huNOG mice, whereas T cell infiltrate was lower in tumors of 89Zr-CD3xKLH and 89Zr-KLHxKLH injected huNOG mice. Spleens of huNOG mice showed CD3+ specific uptake as 89Zr-ERY974 and 89Zr-CD3xKLH uptake were higher than 89Zr-KLHxKLH uptake(P&lt;0.05), whereas spleen uptake in NOG mice of the 3 tracers was similar. Moreover, in huNOG CD3+ mesenteric lymph nodes 89Zr-ERY974 uptake was higher than 89Zr-KLHxKLH uptake (P&lt;0.05)

CONCLUSION: 89Zr-ERY974 demonstrates specific tumor uptake in NOG and huNOG mice, while in huNOG mice tumor uptake colocalized with T cell rich infiltrate and also uptake in in spleen and lymph nodes was observed.

Citation Format: Stijn J. Waaijer, Danique Giesen, Takahiro Ishiguro, Yuji Sano, Norihisa Ohishi, Athos Gianella-Borradori, Carolien P. Schröder, Elisabeth G. de Vries, Marjolijn N. Lub-de Hooge. PET imaging with the bispecific 89Zr-antibody ERY974 targeting CD3 and glypican 3 in tumor-bearing mouse models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3028.

An anti–glypican 3/CD3 bispecific T cell–redirecting antibody for treatment of solid tumors

Cancer care is being revolutionized by immunotherapies such as immune checkpoint inhibitors, engineered T cell transfer, and cell vaccines. The bispecific T cell–redirecting antibody (TRAB) is one such promising immunotherapy, which can redirect T cells to tumor cells by engaging CD3 on a T cell and an antigen on a tumor cell. Because T cells can be redirected to tumor cells regardless of the specificity of T cell receptors, TRAB is considered efficacious for less immunogenic tumors lacking enough neoantigens. Its clinical efficacy has been exemplified by blinatumomab, a bispecific T cell engager targeting CD19 and CD3, which has shown marked clinical responses against hematological malignancies. However, the success of TRAB in solid tumors has been hampered by the lack of a target molecule with sufficient tumor selectivity to avoid “on-target off-tumor” toxicity. Glypican 3 (GPC3) is a highly tumor-specific antigen that is expressed during fetal development but is strictly suppressed in normal adult tissues. We developed ERY974, a whole humanized immunoglobulin G–structured TRAB harboring a common light chain, which bispecifically binds to GPC3 and CD3. Using a mouse model with reconstituted human immune cells, we revealed that ERY974 is highly effective in killing various types of tumors that have GPC3 expression comparable to that in clinical tumors. ERY974 also induced a robust antitumor efficacy even against tumors with nonimmunogenic features, which are difficult to treat by inhibiting immune checkpoints such as PD-1 (programmed cell death protein–1) and CTLA-4 (cytotoxic T lymphocyte–associated protein–4). Immune monitoring revealed that ERY974 converted the poorly inflamed tumor microenvironment to a highly inflamed microenvironment. Toxicology studies in cynomolgus monkeys showed transient cytokine elevation, but this was manageable and reversible. No organ toxicity was evident. These data provide a rationale for clinical testing of ERY974 for the treatment of patients with GPC3-positive solid tumors.

Abstract 3653: Combining ERY974, a novel T cell-redirecting bispecific antibody targeting glypican-3, with chemotherapy profoundly improved antitumor efficacy over its monotherapy in xenograft model

Background: ERY974 is a humanized IgG4 bispecific T cell-redirecting antibody (TRAB) currently in Phase 1 clinical trial (NCT02748837). ERY974 consists of a common light chain and two different heavy chains that respectively recognize glypican-3 (GPC3) and CD3. The Fc portion of ERY974 is modified to lose FcγR binding to prevent GPC3-independent Fc-mediated effector function. However, binding activity to FcRn, an important factor in the PK profile of IgG, is maintained. ERY974 simultaneously binds to GPC3 on the cancer cell surface and to CD3 on the T cell surface, and induces TRAB-dependent cellular cytotoxicity mediated by the potent effector function of T cells. ERY974 shows strong antitumor activity against gastric, lung, ovarian, head & neck, and esophageal cancer-derived xenograft tumors in a non-obese diabetic/severe combined immunodeficiency (NOD-SCID) mouse model injected with human T cells. Cancer immunotherapy, as represented by immune checkpoint inhibitors such as PD-1, PD-L1, and CTLA-4 antibodies, has recently been demonstrating remarkable clinical benefit in various tumor types. However, the number of patients who have survival benefit is limited, and combining cancer immunotherapy with other agents is required to improve the efficacy. Although ERY974 monotherapy is expected to show clinical activity based on the preclinical data, we examined whether further improvement of ERY974-induced efficacy is attained by combination with chemotherapy.

Method & Results: We evaluated the combination effect of ERY974 with chemotherapy against xenograft tumors of MKN45 (gastric cancer) or NCI-H446 (lung cancer) either in a NOD-SCID mouse model injected with human T cells or in a humanized non-obese diabetic/shi-scid/IL-2Rγnull model in which differentiated human T cells are constitutively supplied. Although ERY974 monotherapy shows only minor antitumor effect against MKN45 and NCI-H446, combination therapy remarkably enhanced efficacy. In particular, ERY974 in combination with paclitaxel or cisplatin in NCI-H446 tumors caused a tumor disappearance without regrowth for a long period. Conclusion: These preclinical data suggest the possibility that the strategy of combining ERY974 with chemotherapy may succeed in increasing the clinical benefit. Now the combination effect is being further investigated to clarify the mechanism.

Citation Format: Yuji Sano, Yumiko Azuma, Toshiaki Tsunenari, Yasuko Kinoshita, Yoko Kayukawa, Hironori Mutoh, Yoko Miyazaki, Takahiro Ishiguro, Shohei Kishishita, Yoshiki Kawabe, Mika Endo. Combining ERY974, a novel T cell-redirecting bispecific antibody targeting glypican-3, with chemotherapy profoundly improved antitumor efficacy over its monotherapy in xenograft model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3653. doi:10.1158/1538-7445.AM2017-3653

A phase I dose escalation (DE) and cohort expansion (CE) study of ERY974, an anti-glypican 3 (GPC3)/CD3 bispecific antibody, in patients with advanced solid tumors

TPS3112

Background: Bispecific antibodies to facilitate T-cell directed cytotoxicity (TDCC) is a proven therapy strategy in cancer. ERY974 is a humanized IgG4 bispecific antibody designed to simultaneously bind to cytotoxic T-cell CD3 receptors and GPC3 (a glycoprotein expressed on cell surface of several tumors) to elicit T-cell activation and TDCC. The objectives of this multi-country, phase 1 study of ERY974 is to determine the maximum tolerated dose (MTD) and to perform a preliminary assessment of anti-tumor activity in patients with solid tumors expressing GPC3. Methods: ERY974 is dosed IV weekly. All patients receive premedication with dexamethasone (DEX) prior to 1st and 2nd ERY974 dose. DE uses an accelerated titration design (ATD), then a modified continual reassessment method (mCRM) described by one-parameter logistic model, to determine MTD, where DLT occurrence rate is 0.25. Combining ATD and mCRM is to permit rapid dose escalation whilst minimizing patient numbers exposed to sub-therapeutic doses, and to accurately determine MTD. Once grade 2 (G2) cytokine release syndrome (CRS) is observed, DEX is increased. If ≥G2 CRS is again observed, then at all subsequent doses the 1st dose of ERY974 is fixed at the last dose level when < G2 CRS was not seen, DE proceeds with the 2nd dose. ATD commences with n = 1, increasing to n = 3 once drug-related ≥G2 toxicity is seen. mCRM starts after 1st dose limiting toxicity (DLT), with the modifications of at least 3 patients required to dose escalate and up to 1.5x increment to minimize risk of toxicity. CE has 3 arms: GPC3+ gastric/gastroesophageal junction adenocarcinoma; GPC3+ squamous esophageal cancer; and other GPC3+ tumors. A 2-stage design is used to allow CE to stop early for futility. Subjects are adults with histologically confirmed, measurable malignant solid tumors and/or metastatic disease not amenable to standard therapy, and life expectancy ≥3 months. Patients with > 1cm or > 1 brain metastasis, current/previous interstitial lung disease, and acute/chronic infection are excluded. 3 cohorts have been completed without DLT. Cohort 4 began in January 2017. Clinical trial information: NCT02748837.

Entire CD3ε, δ, and γ humanized mouse to evaluate human CD3-mediated therapeutics

T cell–mediated immunotherapy is an attractive strategy for treatment in various disease areas. In this therapeutic approach, the CD3 complex is one of the key molecules to modulate T cell functions; however, in many cases, we cannot evaluate the drug candidates in animal experiments because the therapeutics, usually monoclonal antibodies specific to human CD3, cannot react to mouse endogenous Cd3. Although immunodeficient mice transfused with human hematopoietic stem or precursor cells, known as humanized mice, are available for these studies, mice humanized in this manner are not completely immune competent. In this study we have succeeded in establishing a novel mouse strain in which all the three components of the Cd3 complex — Cd3ε, Cd3δ, and Cd3γ — are replaced by their human counterparts, CD3E, CD3D, and CD3G. Basic immunological assessments have confirmed that this strain of human CD3 EDG–replaced mice are entirely immune competent, and we have also demonstrated that a bispecific antibody that simultaneously binds to human CD3 and a tumor-associated antigen (e.g. ERBB2 or GPC3) can be evaluated in human CD3 EDG–replaced mice engrafted with tumors. Our mouse model provides a novel means to evaluate the in vivo efficacy of human CD3–mediated therapy.

Abstract 1482: Anti-GPC3 TRAB, a first-in-class T cell-redirecting bispecific antibody targeting glypican-3 with potent in vitro and in vivo antitumor efficacy against solid tumors

We present efficacy data for the T cell-redirecting antibody (TRAB) with highly potent anti-tumor efficacy. Anti-Glypican-3 (GPC3) TRAB is a humanized IgG4 bispecific antibody that simultaneously binds to GPC3 on the cancer cell surface and to CD3 on the T cell surface. Anti-GPC3 TRAB utilizes T cells as effectors to induce strong TRAB dependent cellular cytotoxicity (TDCC) in the presence of GPC3-expressing cells. Treatment with anti-GPC3 TRAB first activates T cells by increasing the expression of CD25 and CD69 and also upregulating cytokines IL-2, IL-4, IL-6, IL 10, IFNγ, and TNF, and then it enhances the proliferation of T cells. Anti-GPC3 TRAB showed antitumor activity against xenograft tumors derived from various cancer types — MKN-74 (human gastric adenocarcinoma), PC-10 (human lung squamous cell carcinoma), TOV-21G (human ovarian clear cell carcinoma), and KYSE70 (human esophageal squamous cell carcinoma) — in a NOD-SCID mouse model injected with human T cells. Although recent immunotherapy, as represented by immune check point inhibitors PD-1, PD-L1, and CTLA-4 antibodies, showed promising efficacy in human, not every patient can benefit from this immunotherapy, because the significant efficacy shown in patients by a blockade of immune checkpoints is closely related to the tumor microenvironment. The immune check point inhibitors show high efficacy against inflamed tumors, because these have been sufficiently infiltrated by cytotoxic T cells that recognize cancer-specific antigens. However, they do not have efficacy against non inflamed tumors. In an immunocompetent mouse model using human CD3 transgenic mice, neither the inhibitors that block immune checkpoints (such as PD-1, PD-L1 and CTLA-4) nor a conventional ADCC antibody recognizing GPC3 could show significant efficacy against a poorly immunogenic LLC1/hGPC3 tumor. However, anti-GPC3 TRAB showed efficacy against this poorly immunogenic tumor by utilizing any kind of T cell as effectors irrespective of TCR specificity, including not only CD8-positive but also CD4-positive T cells.

The studies we present show that anti-GPC3 TRAB is a promising drug with high efficacy utilizing all kinds of T cells as effectors. The compound is expected to have efficacy even in patients with poorly immunogenic tumors, in which an immune checkpoint blockade fails to show efficacy.

Citation Format: Yasuko Kinoshita, Takahiro Ishiguro, Yuji Sano, Yumiko Azuma, Toshiaki Tsunenari, Natsuki Ono, Yoko Kayukawa, Otoya Ueda, Naoko A. Wada, Hiroshi Hino, Koichi Jishage, Hirotake Shiraiwa, Mika Kamata-Sakurai, Junichi Nezu, Mika Endo. Anti-GPC3 TRAB, a first-in-class T cell-redirecting bispecific antibody targeting glypican-3 with potent in vitro and in vivo antitumor efficacy against solid tumors. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1482.

Endocytoscopic observation of various esophageal lesions at ×600: can nuclear abnormality be recognized?

Endocytoscopy (ECS) is a novel endoscopic technique that allows detailed diagnostic examination of the gastrointestinal tract at the cellular level. We previously reported that use of ECS at ×380 magnification (GIF-Y0002) allowed a pathologist to diagnose esophageal squamous cell carcinoma (ESCC) with high sensitivity (94.9%) but considerably low specificity (46.7%) because this low magnification did not reveal information about nuclear abnormality. In the present study, we used the same magnifying endoscope to observe various esophageal lesions, but employed digital 1.6-fold magnification to achieve an effective magnification of ×600, and evaluated whether this improved the diagnostic accuracy in distinguishing neoplastic from non-neoplastic lesions.We examined the morphology of surface cells using vital staining with toluidine blue and compared the histological features of 40 cases, including 19 case of ESCC and 21 non-neoplastic esophageal lesions (18 cases of esophagitis, 1 case of glycogenic acanthosis, 1 case of leiomyoma, and 1 case of normal squamous epithelium). One endoscopist classified the lesions using the type classification, and we consulted one pathologist for judgment of the ECS images as 'neoplastic', 'borderline', or 'non-neoplastic'. At ×600 magnification, the pathologist confirmed that nuclear abnormality became evident, in addition to the information about nuclear density provided by observation at ×380. The overall sensitivity and specificity with which the endoscopist was able to predict neoplastic lesions using the type classification was 100% (19/19) and 90.5% (19/21), respectively, in comparison with values of 94.7% (18/19 cases) and 76.2% (16/21), respectively, for the pathologist using a magnification of ×600. The pathologist diagnosed two non-neoplastic lesions and one case of ESCC showing an apparent increase of nuclear density with weak nuclear abnormality as 'borderline'. Among the 21 non-cancerous lesions, two cases of esophagitis that were misdiagnosed by the endoscopist were also misinterpreted as 'neoplastic' by the pathologist. We have shown, by consultation with a pathologist, that an ECS magnification of ×600 (on a 19-inch monitor) is adequate for recognition of nuclear abnormality. We consider that it is feasible to diagnose esophageal neoplasms on the basis of ECS images, and that biopsy histology can be omitted if a combination of increased nuclear density and nuclear abnormality is observed.

Circulating biomarkers in hepatocellular carcinoma

PURPOSE

Our aims are to determine levels of circulating cellular and protein biomarkers in hepatocellular carcinoma (HCC) patients and to analyse any relationships with clinical parameters.

METHODS

Fifty-four consenting patients were recruited. Circulating tumour cells (CTCs) were enumerated (by CellSearch) and characterised via filtration [by isolation by size of epithelial tumour cells (ISET)] with downstream immunohistochemistry (IHC). Glypican-3 (GPC3) expression in tumour biopsies and CTCs (by IHC) was compared, and levels of circulating caspase-cleaved and full-length cytokeratin 18 (CK18, measured using M30 and M65 ELISAs) were examined as a putative prognostic factor and marker of tumour burden.

RESULTS

CTCs were identified in 14 out of 50 (28%) patients by CellSearch and in 19 out of 19 (100%) patients by ISET. The presence of GPC3-positive CTCs by ISET was 100% concordant with the presence of GPC3-positive cells in the original tumour (n = 5). No statistically significant correlations were observed between CTC number and clinical characteristics, although trends were noted between CTC subtypes, Child-Pugh score and tumour node metastasis stage. Serum M30 and M65 levels (as continuous variables) significantly correlated with overall survival (OS) in a univariate analysis (p = 0.003 and p < 0.001, respectively); M65 levels remained statistically significant in a multivariate analysis (p = 0.029).

CONCLUSIONS

This is the first study to detect GPC3-positive CTCs in HCC, important for drug development with this target. The significant association of circulating CK18 with OS in HCC further exemplifies the utility of circulating biomarkers in cancer.

Femtosecond-laser-driven photoelectron-gun for time-resolved cathodoluminescence measurement of GaN

A rear-excitation femtosecond-laser-driven photoelectron gun (PE-gun) is developed for measuring time-resolved cathodoluminescence (TRCL) spectrum of wide bandgap materials and structures such as semiconductors and phosphors. The maximum quantum efficiency of a 20-nm-thick Au photocathode excited using a frequency-tripled Al(2)O(3):Ti laser under a rear-excitation configuration is 3.6×10(-6), which is a reasonable value for a PE-gun. When the distance between the front edge of the PE-gun and the observation point is 10 mm, the narrowest electron-beam (e-beam) diameter is 19 μm, which corresponds to one tenth of the laser-beam diameter and is comparable to the initial e-beam diameter of a typical W hair-pin filament of thermionic electron-gun. From the results of TRCL measurements on the freestanding GaN grown by the ammonothermal method and a GaN homoepitaxial film grown by metalorganic vapor phase epitaxy, overall response time for the present TRCL system is estimated to be 8 ps. The value is the same as that of time-resolved photoluminescence measurement using the same excitation laser pulses, meaning that the time-resolution is simply limited by the streak-camera, not by the PE-gun performance. The result of numerical simulation on the temporal e-beam broadening caused by the space-charge-effect suggests that the present PE-gun can be used as a pulsed e-beam source for spatio-time-resolved cathodoluminescence, when equipped in a scanning electron microscope.

Acute generalized exanthematous pustulosis during the puerperal period: a case report

BACKGROUND

Acute generalized exanthematous pustulosis (AGEP) is an uncommon adverse cutaneous reaction, most commonly associated with drugs.

CASE

A 38-year-old primigravida whose labor had been induced developed erythema over her chest and abdomen. She was transferred to our department after a failed vacuum extraction, and delivered a mature infant by forceps. On day three postpartum she developed a 40.4 degrees C fever. Although ceftriaxone was administered, her fever persisted (>38 degreesC). On day six of the puerperium, diffuse non-follicular pustules appeared over her neck and trunk, and AGEP was suspected. Two days after ceftriaxone was withdrawn, the eruptions started to resolve without any medical intervention.

CONCLUSION

Once the diagnosis of AGEP has been made, the antibiotics being administered must be discontinued. If continued treatment is required, pharmacologically distinct antibiotics must be used instead to aid the rapid self-limitation of the disease.

Prognostic significance of circumferential cell surface immunoreactivity of glypican-3 in hepatocellular carcinoma

BACKGROUND

GC33 is a recently developed monoclonal antibody against human glypican-3 (GPC3), which is significantly upregulated in hepatocellular carcinoma (HCC). GC33 recognizes a GPC3 ectodomain and shows significant antitumour activity in vivo. Thus, humanized GC33 antibody may be a promising tool for treating HCC having cell surface GPC3 expression.

AIMS

This study aims to determine the specificity, subcellular localization and prognostic impact of GPC3 immunoreactivity detected by GC33 in HCC clinical specimens.

METHODS

Immunohistochemical analysis was performed for 194 cases of resected HCC and prognostic analysis was performed for 185 eligible cases. Two antigen retrieval methods (autoclave and protease pretreatments) were used for immunohistochemistry and compared. The immunoscore system reflecting circumferential membranous GPC3 immunoreactivity was developed using either the autoclave or protease methods. The GPC3 mRNA level was analysed by quantitative real-time reverse transcription-polymerase chain reaction.

RESULTS

GC33 immunostaining after autoclave is a sensitive method and revealed the GPC3 expression (≥20% of tumour cells) in the majority (77%) of HCC samples tested. Alternatively, protease pretreatment showed lower sensitivity, but was superior for evaluating the intensity and subcellular localization of GPC3. Correlation between immunoscores and the GPC3 mRNA level was also confirmed. Subsequent clinicopathological analysis revealed worse prognoses in HCC patients with circumferential membranous GPC3 immunoreactivity. For HCC patients with hepatitis C virus (HCV) infection in particular, the high membranous GPC3 immunoreactivity was an independent prognostic factor for disease-free survival.

CONCLUSIONS

Circumferential membranous GPC3 immunoreactivity in HCC indicates poorer prognosis particularly in patients with HCV infection.

A defucosylated anti-CD317 antibody exhibited enhanced antibody-dependent cellular cytotoxicity against primary myeloma cells in the presence of effectors from patients

The humanized monoclonal antibody (mAb) against CD317 antigen (anti-HM1.24 antibody; AHM), which is highly expressed on multiple myeloma (MM), induces antibody-dependent cellular cytotoxicity (ADCC). However, the antitumor activity of AHM in the clinical setting has not been clearly demonstrated. In this study, we produced defucosylated AHM and evaluated its potency for clinical application by performing autologous ADCC assays against primary MM cells from patients. Defucosylated AHM that was produced in rat myeloma YB2/0 cells expressing a low level of fucosyltransferase (FUT8) showed significant ADCC activity against three out of six primary MM cells in the presence of autologous PBMC, whereas conventional AHM did not. The results indicate that the potency of AHM to induce ADCC against primary MM cells was insufficient, but was significantly augmented by defucosylation. To generate more homogenous defucosylated monoclonal antibodies (mAb) for fermentation, we disrupted the GFT gene that encodes a GDP-fucose transporter in a CHO/DXB11 cell line by sequential homologous recombination. Analysis of the N-linked oligosaccharide in the defucosylated AHM produced by the established GFT(-/-)CHO cell line showed that a majority (93.4%) of the oligosaccharide was fucose free. The GFT(-/-) cells stably produced defucosylated mAb over passages. These results demonstrate that GTF(-/-)CHO-produced defucosylated AHM (GFTKO-AHM) will be a promising new therapeutic antibody against MM in the clinical setting.

Curative colectomy via minilaparotomy approach without utilizing specific instruments

BACKGROUND

This study evaluated the need for specific instruments when performing a curative resection of colon cancer via a minilaparotomy approach, which has been reported to be a minimally invasive alternative to a laparoscopic approach.

METHODS

The feasibility, safety, and early oncological outcome were compared among 73 patients (first group), in whom a curative resection of colon cancer was performed via a minilaparotomy (skin incision < or =7 cm) utilizing specific instruments (North-bridge retractor system) between September 2002 and March 2005, and 94 patients (second group), in whom a similar procedure was performed without utilizing specific instruments between April 2005 and October 2007.

RESULTS

The two groups did not differ significantly in terms of age, sex, body mass index, site of tumor, level of lymph node dissection, blood loss, UICC stage, number of harvested lymph nodes, incidence of postoperative complications, length of postoperative hospital days, or overall survival, although the frequency of prior abdominal surgery was higher (38.3 vs. 21.9%; P = 0.03) and the median operating time required for a standard lymph node dissection was shorter (120 vs. 135 min; P = 0.03) in the second group.

CONCLUSION

With improved techniques and experience, specific instruments are not necessary for the performance of a curative colectomy via a minilaparotomy approach.

Abstract 2426: Anti-Glypican3 antibody for treatment of human liver cancer

Glypican-3 (GPC3) is a member of the glypican family of heparan sulfate proteoglycans, which are linked to the cell surface through a glycosyl phosphatidyl inositol anchor. GPC3 has been reported to be highly expressed in the majority (70-100%) of HCC, and considered to play a role in the tumorigenesis of HCC. Although the molecular mechanism by which GPC3 functions in tumorigenesis has not been fully elucidated, the high prevalence in HCC has led to considerable interest in GPC3 as a diagnostic marker and therapeutic target.

In this study, we obtained a monoclonal antibody (mAb) against the COOH-terminal part of GPC3, which induced antibody-dependent cellular cytotoxicity (ADCC). The mAb, designated mGC33, exhibited marked tumor growth inhibition of s.c. transplanted Hep G2 and HuH-7 xenografts that expressed GPC3 but did not inhibit growth of the SK-HEP-1 that was negative for GPC3. mGC33 was efficacious even in an orthotopic model; it markedly reduced the blood alpha-fetoprotein levels of mice intrahepatically transplanted with Hep G2 cells. To develop an antibody-based immunotherapy, we generated humanized GC33 (hGC33) by complementarily determining region (CDR) grafting. hGC33 was as efficacious as mGC33 against the Hep G2 xenograft, but hGC33 lacking carbohydrate moieties caused neither ADCC nor tumor growth inhibition. Depletion of CD56+ cells from human peripheral blood mononuclear cells markedly abrogated the ADCC caused by hGC33. The results show that the antitumor activity of hGC33 is mainly attributable to ADCC, and in human, natural killer cell-mediated ADCC is one possible mechanism of the antitumor effects by GC33. We also evaluated the antitumor activity of hGC33 combined with standard chemotherapy agent sorafenib. hGC33 and sorafenib combination was more potent in inhibiting tumor growth than sorafenib alone in the s.c. transplanted Hep G2 xenograft model. Administration of sorafenib alone did not change the GPC3 expression level in xenograft tumor. These suggest that this combination regimen may be clinically useful as an anti-liver cancer therapy.

In careful examination of the safety of hGC33 in nonclinical studies, specific adverse findings on GPC3 expressed tissue or organs were not observed after repeated administration. Therefore hGC33 will provide a novel treatment option for liver cancer patients with GPC3-positive tumors.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2426.

Intrauterine fetal demise due to streptococcal toxic shock syndrome: a case report

BACKGROUND

Toxic shock syndrome caused by group A streptococci (GAS) is rare around the time of delivery, but it may predispose pregnant women to a life-threatening condition.

CASE

A 32-year-old primigravida at 21 weeks of gestation was taken to our hospital with acute severe abdominal pain following fever. On admission the fetus was found to be dead, and intrauterine fetal demise due to placental abruption was suspected. An emergency cesarean section found no sign of placental abruption. Soon after the surgery, the patient went into shock but was successfully treated with intensive care. Although repeated blood cultures failed to detect microorganisms, the patient was positive for streptococcal pyrogenic toxin A, which is a superantigen of GAS.

CONCLUSION

Once GAS infection is suspected, regardless of negative blood cultures, supportive care in the intensive care unit is mandatory.

Involvement of glypican-3 in the recruitment of M2-polarized tumor-associated macrophages in hepatocellular carcinoma

Previously, we demonstrated that membrane expression of glypican-3 (GPC3) stimulates the recruitment of macrophages into human hepatocellular carcinoma (HCC) tissues. However, functional polarization of the macrophages and the chemoattractant factors related to the recruitment has yet to be determined. In this study, to clarify the polarization (M1 or M2) of the macrophages and provide a clue as to the factors involved in the recruitment, we used xenograft models of SK-HEP-1 and SK03 cell lines with undetectable and high-level membrane expression of GPC3, respectively and analyzed the expression profiles of the relevant genes in both xenografts mainly using microarray techniques. Clustering analyses with mouse genome arrays revealed that the SK-HEP-1 and SK03 xenografts showed different expression profiles for M2 macrophage-related genes but not for M1 macrophage-related genes. Many of the M2 macrophage-related genes were upregulated in the SK03 xenografts compared to the SK-HEP-1 xenografts. Additionally, most of the macrophages infiltrating into the SK03 xenografts were positive for M2 macrophage-specific markers. Regarding the chemoattractant factors, the microarray and quantitative real-time PCR analyses revealed that, of the genes reportedly related to macrophage recruitment, CCL5, CCL3 and CSF1 were significantly upregulated in the SK03 xenograft. These findings suggest that the macrophages recruited into GPC3-overexpressing (with membrane expression) HCC are M2-polarized ones and, more specifically, M2 tumor-associated macrophages which are known to promote tumor progression and metastasis, and CCL5, CCL3 and CSF1 are possible candidate genes for the recruitment of macrophages.

Polymorphisms of GSTP1, GSTT1, GSTM1, MTHFR, TS, ERCC1, and ERCC2 in metastatic colorectal cancer treated by first-line mFOLFOX6 chemotherapy

e14628

Background: It was reported that determining functional polymorphisms of genes involved in drug-metabolising pathways and DNA repair may be useful for predicting the response to 5-FU/oxaliplatin chemotherapy in Caucasian patients with metastatic colorectal cancer. This study was performed to examine whether determining these polymorphisms had any clinical value in Asian patients with colorectal cancer receiving 5-FU/oxaliplatin therapy. Methods: Genomic DNA was extracted from peripheral blood lymphocytes (n=25) or colonic mucosa (n=47) in Japanese patients with metastatic colorectal cancer who were receiving first-line therapy with the modified FOLFOX6 regimen followed by FOLFIRI (n=42). Polymorphisms of 5 genes involved in drug metabolism (glutathione S-transferase (GST) P1 (IIe 105 Val), GSTT1 deletion, and GSTM1 deletion, methylenetetrahydrofolate reductase (MTHFR) (Ala 677 Val), and a 6-base pair (bp) deletion in the 3’-untranslated region (UTR) of thymidylate synthase (TS)), and polymorphisms of two DNA repair genes (excision repair cross complementing group 1 (ERCC1): Asp 118 Asn and ERCC2: Lys 751 Gln) were assessed in these patients by PCR-RFLP or the invader technique. Correlations between polymorphisms of these genes and the response to therapy were evaluated. Results: The distribution of the genotypes of GSTP1, GSTT1, TS, ERCC1, and ERCC2 in the present Japanese patients (but not that of GSTM1 or MTHFR), differed significantly from the distribution of these genotypes in a Caucasian population. The response rate and progression-free survival were not correlated with any of the functional polymorphisms investigated. However, patients who had both alleles containing the 6-bp nucleotide fragment in the 3’UTR of TS showed significantly shorter overall survival than those who had at least one allele without the 6-bp nucleotide fragment (p=0.03). Conclusions: These results suggest that 3’UTR polymorphism of TS may be an important predictor of overall survival for Japanese patients with metastatic colorectal cancer receiving first-line 5-FU/oxaliplatin therapy.

No significant financial relationships to disclose.

Histopathological analyses of the antitumor activity of anti-glypican-3 antibody (GC33) in human liver cancer xenograft models: The contribution of macrophages

Previously, we demonstrated the antitumor efficacy of the anti-glypican-3 (GPC3) antibody GC33 in several human liver cancer xenograft models and the important role of antibody-dependent cellular cytotoxicity (ADCC) in the antitumor mechanism of GC33. Involvement of other mechanisms such as modulation of the functions of GPC3 in antitumor activity remains to be elucidated. In this study, we investigated histopathologically time-course changes in xenografts in mice following a single administration of GC33 to clarify the morphological changes contributing to the tumor growth inhibition of GC33, including the changes in GPC3-related factors/components [proliferation, extracellular matrices (ECMs) and macrophage]. Histopathological changes peaked 3-5 d after GC33 administration and included increased tumor cell death, tumor cells with round morphology, multinucleated tumor cells and small spindle/round-like cells (mostly F4/80-positive macrophages). No direct effects of GC33 on proliferation activity of tumor cells were observed. Meanwhile, alteration of ECM structures and a remarkable increase in macrophages was noted in the GC33-treated group. Increase in macrophages was observed mainly in the outer layer of tumor nodules; the area of the increase approximately included the area where the change in tumor cells and ECMs were observed. Interestingly, depletion of macrophages in the xenograft models resulted in a marked reduction of the antitumor activity of GC33. In the in vitro ADCC assay, ADCC was only slightly induced by mouse peritoneal macrophages. These data suggest that macrophages play an important role in the antitumor activity of GC33, which is not likely to be direct ADCC by macrophages themselves.

Anti-glypican 3 antibody as a potential antitumor agent for human liver cancer

Human glypican 3 (GPC3) is preferentially expressed in the tumor tissues of liver cancer patients. In this study, we obtained a monoclonal antibody (mAb) against the COOH-terminal part of GPC3, which induced antibody-dependent cellular cytotoxicity (ADCC). The mAb, designated GC33, exhibited marked tumor growth inhibition of s.c. transplanted Hep G2 and HuH-7 xenografts that expressed GPC3 but did not inhibit growth of the SK-HEP-1 that was negative for GPC3. GC33 was efficacious even in an orthotopic model; it markedly reduced the blood alpha-fetoprotein levels of mice intrahepatically transplanted with Hep G2 cells. Humanized GC33 (hGC33) was as efficacious as GC33 against the Hep G2 xenograft, but hGC33 lacking carbohydrate moieties caused neither ADCC nor tumor growth inhibition. Depletion of CD56+ cells from human peripheral blood mononuclear cells markedly abrogated the ADCC caused by hGC33. The results show that the antitumor activity of hGC33 is mainly attributable to ADCC, and in human, natural killer cell-mediated ADCC is one possible mechanism of the antitumor effects by GC33. hGC33 will provide a novel treatment option for liver cancer patients with GPC3-positive tumors.

COX-2 inhibition attenuates cough reflex sensitivity to inhaled capsaicin in patients with asthma

BACKGROUND AND OBJECTIVE

Cyclooxygenase (COX) is an enzyme that converts arachidonic acid to prostanoids. There are two isoforms of COX, namely COX-1 and COX-2. COX-2 is highly inducible by several stimuli and is associated with inflammation. Recent studies have shown that COX-2 is upregulated in the airway epithelium of patients with asthma but little is known about the role it plays in cough, a common symptom of bronchial asthma. This study was designed to investigate the role of COX-2 in cough reflex sensitivity in patients with asthma.

PATIENTS AND METHODS

The effect of etodolac, a potent COX-2 inhibitor, on cough response to inhaled capsaicin was examined in 17 patients with stable asthma in a randomized, placebo-controlled crossover study. Capsaicin cough threshold, defined as the lowest concentration of capsaicin eliciting 5 or more coughs, was measured as an index of airway cough reflex sensitivity.

RESULTS

The geometric mean (geometric SEM) cough threshold was significantly increased after a 2-week treatment program with oral etodolac (200 mg twice a day) compared with placebo (36.7 [1.2] vs 21.6 [1.2] gM, P<.02).

CONCLUSIONS

These findings indicate that COX-2 may be a possible modulator augmenting airway cough reflex sensitivity in asthmatic airways.

Anti-glypican 3 antibodies cause ADCC against human hepatocellular carcinoma cells

Glypican 3 (GPC3), a GPI-anchored heparan sulfate proteoglycan, is expressed in the majority of hepatocellular carcinoma (HCC) tissues. Using MRL/lpr mice, we successfully generated a series of anti-GPC3 monoclonal antibodies (mAbs). GPC3 was partially cleaved between Arg358 and Ser359, generating a C-terminal 30-kDa fragment and an N-terminal 40-kDa fragment. All mAbs that induced antibody-dependent cellular cytotoxicity (ADCC) and/or complement-dependent cytotoxicity (CDC) against cells expressing GPC3 recognized the 30-kDa fragment, indicating that the C-terminal region of GPC3 serves as an epitope for mAb with ADCC and/or CDC inducing activities. Chimeric mAbs with Fc replaced by human IgG1 were created from GC33, one of the mAbs that reacted with the C-terminal 30-kDa fragment. Chimeric GC33 induced not only ADCC against GPC3-positive human HCC cells but also was efficacious against the Huh-7 human HCC xenograft. Thus, mAbs against the C-terminal 30-kDa fragment such as GC33 are useful in therapy targeting HCC.