Summary Catumaxomab is a trifunctional antibody (trAb) characterized by its unique ability to bind three different cell types: tumor cells, T-cells, and accessory cells. It has two different ...antigen-binding specificities: one for epithelial cell adhesion molecule (EpCAM) on tumor cells and one for the CD3 antigen on T-cells. Catumaxomab also binds to type I, IIa, and III Fcγ receptors (FcγR) on accessory cells, e.g. macrophages, dendritic cells, and natural killer cells, via its intact Fc region. Its anti-tumor activity results from T-cell-mediated lysis, antibody-dependent cell-mediated cytotoxicity, and phagocytosis via activation of FcγR-positive accessory cells. Importantly, no additional activation of immune cells is necessary for effective tumor eradication by catumaxomab, which represents a self-supporting system. Catumaxomab’s efficacy and safety have been demonstrated in a pivotal phase II/III study and supporting phase I/II studies. It is administered as four intraperitoneal (i.p.) infusions on days 0, 3, 7, and 10 at doses of 10, 20, 50, and 150 μg, respectively. Catumaxomab has been approved in the European Union since April 2009 for the i.p. treatment of malignant ascites (MA) in patients with EpCAM-positive carcinomas where standard therapy is not available or no longer feasible. Catumaxomab is the first trAb and the first drug worldwide to be approved specifically for the treatment of MA. It is in clinical trials in a number of other indications including ovarian and gastric cancer. Alternative routes of administration are also under evaluation to further exploit the therapeutic potential of catumaxomab in EpCAM-positive carcinomas.
Transurethral resection of the tumor (TUR-B) followed by adjuvant intravesical treatment with cytostatic drugs or Bacillus Calmette–Guérin (BCG) as standard therapy of non-muscle-invasive bladder ...cancer (NMIBC) is associated with a high recurrence rate of about 60–70%, considerable side effects and requires close monitoring. Alternative treatment options are warranted. Two patients with epithelial cell adhesion molecule (EpCAM)-positive recurrent non-muscle invasive bladder cancer were treated the first time by an intravesical administration of the trifunctional bispecific EpCAM targeting antibody catumaxomab (total dosage of 470 and 1120 µg, respectively). The binding and killing activity of catumaxomab in urine milieu was evaluated in vitro. In contrast to its previous systemic application catumaxomab was well tolerated without any obvious signs of toxicity. Relevant cytokine plasma levels were not detected and no significant systemic drug release was observed. The induction of a human anti-mouse-antibody (HAMA) reaction was either absent or untypically weak contrary to the high immunogenicity of intraperitoneal applied catumaxomab. Tumor cells that were detectable in urine patient samples disappeared after catumaxomab therapy. Endoscopically confirmed recurrence-free intervals were 32 and 25 months. Our data suggest that intravesical administration of catumaxomab in NMIBC is feasible, safe and efficacious, thus arguing for further clinical development of catumaxomab in this indication.
Malignant ascites is a common manifestation of advanced cancers, and treatment options are limited. The trifunctional antibody catumaxomab (anti‐epithelial cell‐adhesion molecule x anti‐CD3) ...represents a targeted immunotherapy for the intraperitoneal (i.p.) treatment of malignant ascites secondary to epithelial cancers. In this phase II/III trial (EudraCT 2004‐000723‐15; NCT00836654), cancer patients (n = 258) with recurrent symptomatic malignant ascites resistant to conventional chemotherapy were randomized to paracentesis plus catumaxomab (catumaxomab) or paracentesis alone (control) and stratified by cancer type (129 ovarian and 129 nonovarian). Catumaxomab was administered as an i.p. infusion on Days 0, 3, 7 and 10 at doses of 10, 20, 50 and 150 μg, respectively. The primary efficacy endpoint was puncture‐free survival. Secondary efficacy parameters included time to next paracentesis, ascites signs and symptoms and overall survival (OS). Puncture‐free survival was significantly longer in the catumaxomab group (median 46 days) than the control group (median 11 days) (hazard ratio = 0.254: p < 0.0001) as was median time to next paracentesis (77 versus 13 days; p < 0.0001). In addition, catumaxomab patients had fewer signs and symptoms of ascites than control patients. OS showed a positive trend for the catumaxomab group and, in a prospectively planned analysis, was significantly prolonged in patients with gastric cancer (n = 66; 71 versus 44 days; p = 0.0313). Although adverse events associated with catumaxomab were frequent, they were manageable, generally reversible and mainly related to its immunologic mode of action. Catumaxomab showed a clear clinical benefit in patients with malignant ascites secondary to epithelial cancers, especially gastric cancer, with an acceptable safety profile.
Intraoperative blood salvage (IBS) is regarded as an alternative to allogeneic blood transfusion excluding the risks associated with allogeneic blood. Currently, IBS is generally avoided in tumor ...surgeries due to concern for potential metastasis caused by residual tumor cells in the erythrocyte concentrate.
The feasibility, efficacy and safety aspects of the new developed Catuvab procedure using the bispecific trifunctional antibody Catumaxomab was investigated in an ex-vivo pilot study in order to remove residual EpCAM positive tumor cells from the autologous erythrocyte concentrates (EC) from various cancer patients, generated by a IBS device.
Tumor cells in intraoperative blood were detected in 10 of 16 patient samples in the range of 69-2.6 × 10
but no residual malignant cells in the final erythrocyte concentrates after Catuvab procedure. IL-6 and IL-8 as pro-inflammatory cytokines released during surgery, were lowered in mean 28-fold and 52-fold during the Catuvab procedure, respectively, whereas Catumaxomab antibody was detected in 8 of 16 of the final EC products at a considerable decreased and uncritical residual amount (37 ng in mean).
The preliminary study results indicate efficacy and feasibility of the new medical device Catuvab allowing potentially the reinfusion of autologous erythrocyte concentrates (EC) produced by IBS device during oncological high blood loss surgery. An open-label, multicenter clinical study on the removal of EpCAM-positive tumor cells from blood collected during tumor surgery using the Catuvab device is initiated to validate these encouraging results.
Bispecific antibodies (bsAbs) can efficiently mediate tumor cell killing by redirecting preactivated or costimulated T cells to disseminated tumor cells, especially in a minimal residual disease ...situation. This study demonstrates that the trifunctional bsAb BiLu is able to kill tumor cells very efficiently without any additional costimulation of effector cells in vitro and in vivo. Remarkably, this bsAb also induces a long-lasting protective immunity against the targeted syngeneic mouse tumors (B16 melanoma and A20 B-cell lymphoma, respectively). A strong correlation was observed between the induction of a humoral immune response with tumor-reactive antibodies and the survival of mice. This humoral response was at least in part tumor specific as shown in the A20 model by the detection of induced anti-idiotype antibodies. Both the survival of mice and antitumor titers were significantly diminished when F(ab′)2 fragments of the same bsAb were applied, demonstrating the importance of the Fc region in this process. With the use of T-cell depletion, a contribution of a cellular antitumor response could be demonstrated. These results reveal the necessity of the Fc region of the bsAb with its potent immunoglobulin subclass combination mouse immunoglobulin G2a (IgG2a) and rat IgG2b. The antigen-presenting system seems to be crucial for achieving an efficient tumor cell killing and induction of long-lasting antitumor immunity. Hereby, the recruitment and activation of accessory cells by the intact bsAb is essential.
Despite advances in treating high-risk neuroblastoma, 50-60% of patients still suffer relapse, necessitating new treatment options. Bispecific trifunctional antibodies (trAbs) are a promising new ...class of immunotherapy. TrAbs are heterodimeric IgG-like molecules that bind CD3 and a tumor-associated antigen simultaneously, whereby inducing a TCR-independent anti-cancer T cell response. Moreover, via their functional Fc region they recruit and activate cells of the innate immune system like antigen-presenting cells potentially enhancing induction of adaptive tumor-specific immune responses.
We used the SUREK trAb, which is bispecific for GD2 and murine Cd3. Tumor-blind trAb and the monoclonal ch14.18 antibody were used as controls. A co-culture model of murine dendritic cells (DCs), T cells and a neuroblastoma cell line was established to evaluate the cytotoxic effect and the T cell effector function in vitro. Expression of immune checkpoint molecules on tumor-infiltrating T cells and the induction of an anti-neuroblastoma immune response using a combination of whole cell vaccination and trAb therapy was investigated in a syngeneic immunocompetent neuroblastoma mouse model (NXS2 in A/J background). Finally, vaccinated mice were assessed for the presence of neuroblastoma-directed antibodies. We show that SUREK trAb-mediated effective killing of NXS2 cells in vitro was strictly dependent on the combined presence of DCs and T cells.
Using a syngeneic neuroblastoma mouse model, we showed that vaccination with irradiated tumor cells combined with SUREK trAb treatment significantly prolonged survival of tumor challenged mice and partially prevent tumor outgrowth compared to tumor vaccination alone. Treatment led to upregulation of programmed cell death protein 1 (Pd-1) on tumor infiltrating T cells and combination with anti-Pd-1 checkpoint inhibition enhanced the NXS2-directed humoral immune response.
Here, we provide first preclinical evidence that a tumor vaccination combined with SUREK trAb therapy induces an endogenous anti-neuroblastoma immune response reducing tumor recurrence. Furthermore, a combination with anti-Pd-1 immune checkpoint blockade might even further improve this promising immunotherapeutic concept in order to prevent relapse in high-risk neuroblastoma patients.
The Triomab® family of trifunctional, bispecific antibodies that maintain an IgG-like shape are novel tumor targeting agents. These chimeras consist of two half antibodies, each with one light and ...one heavy chain, that originate from parental mouse IgG2a and rat IgG2b isotypes. This combination allows cost-effective biopharmaceutical manufacturing at an industrial scale since this specific mouse/rat isotype combination favors matching of corresponding antibody halves during production by means of quadroma technology. Whereas every Triomab® family member is composed of an anti-CD3 rat IgG2b half antibody for T cell recognition, the antigen binding site presented by the mouse IgG2a isotype is exchangeable. Several Triomab® antibodies have been generated that bind to tumor-associated antigens, e.g., EpCAM (catumaxomab), HER2/neu (ertumaxomab), CD20 (FBTA05), gangliosides GD2/GD3 (Ektomun®), on appropriate tumor target cells associated with carcinomas, lymphomas or melanomas. Catumaxomab (Removab®) was launched in Europe for treatment of malignant ascites in April 2009. Here, we report the structural and functional characterization this product. Mass spectrometry revealed an intact mass of 150511 Dalton (Da) and 23717 Da, 24716 Da, 51957 Da and 52019 Da of the reduced and alkylated rat light chain, mouse light chain, rat heavy chain, mouse heavy chain chains, respectively. The observed masses were in agreement with the expected masses based on the amino acid sequence obtained from cDNA sequencing. The glycosylation profile was similar to other human IgG consisting of biantennary oligosaccharides with different numbers of terminal galactose. CD spectroscopy showed mainly β-sheets secondary structure that is typical for IgG antibodies. Binding measurement revealed the unique trifunctional features of catumaxomab. Other analytical tools were used to evaluate characteristics of catumaxomab preparations, including the presence of isoforms and aggregates.
Oxidation of methionine residues and deamidation of asparagine residues are the major causes of chemical degradation of biological pharmaceuticals. The mechanism of these non-enzymatic chemical ...reactions has been studied in great detail. However, the identification and quantification of oxidation and deamidation sites in a given protein still remains a challenge. In this study, we identified and characterized several oxidation and deamidation sites in a rat/mouse hybrid antibody. We evaluated the effects of the sample preparation on oxidation and deamidation levels and optimized the peptide mapping method to minimize oxidation and deamidation artifacts. Out of a total number of 18 methionine residues, we identified six methionine residues most susceptible to oxidation. We determined the oxidation rate of the six methionine residues using 0.05% H
2O
2 at different temperatures. Methionine residue 256 of the mouse heavy chain showed the fastest rate of oxidation under those conditions with a half life of approximately 200
min at 4
°C and 27
min at 37
°C. We identified five asparagine residues prone to deamidation under accelerated conditions of pH 8.6 at 37
°C. Kinetic characterization of the deamidation sites showed that asparagine residue 218 of the rat heavy chain exhibited the fastest rate of deamidation with a half live of 1.5 days at pH 8.6 and 37
°C. Analysis of antibody isoforms using free flow electrophoresis showed that deamidation is the major cause of the charged variants of this rat/mouse hybrid antibody.
WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT
• The trifunctional antibody catumaxomab is a highly effective anti‐cancer therapeutic that is administered to patients suffering from malignant ascites ...intraperitoneally (i.p.) in microgram (µg) doses. So far, no clinical pharmacokinetic data are available.
WHAT THIS STUDY ADDS
• Catumaxomab attains effective local concentrations in the ascites fluid and shows low systemic exposure with an acceptable safety profile confirming the appropriateness of the i.p. application scheme.
AIMS Catumaxomab is the first EMEA approved trifunctional anti‐EpCAM×anti‐CD3 antibody for the treatment of cancer patients with malignant ascites. A phase II pharmacokinetic study was conducted to determine local and systemic antibody concentrations and anti‐drug antibody (ADA) development.
METHODS Thirteen cancer patients with symptomatic malignant ascites were treated with four ascending doses of 10, 20, 50, and 150 µg catumaxomab intraperitoneally (i.p.) infused on days 0, 3, 6 or 7 and 10. The pharmacokinetics of catumaxomab were studied by implementation of supportive data from a non clinical mouse tumour model. Additionally, ADA development was monitored.
RESULTS Ten out of 13 patients were evaluable for pharmacokinetic analysis. Catumaxomab became increasingly concentrated in ascites during the course of treatment, attaining effective concentrations in the ng ml−1 range. Catumaxomab remained immunologically active even after several days in the circulation. The observed systemic catumaxomab exposure was low (<1%), with a maximal median plasma concentration (Cmax) of 403 pg ml−1. The mean elimination half‐life in the plasma was 2.13 days. All patients developed ADA, but not before the last infusion. High observed inter‐individual variability and low systemic exposure may be explained by the inverse correlation between tumour burden, effector cell numbers and systemic antibody bioavailability as demonstrated in a defined mouse tumour model.
CONCLUSIONS Based on the high and effective local concentrations, low systemic exposure and acceptable safety profile, we confirmed that the i.p. application scheme of catumaxomab for the treatment of malignant ascites is appropriate.
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