Antibodies and related products are the fastest growing class of therapeutic agents. By analysing the regulatory approvals of IgG-based biotherapeutic agents in the past 10 years, we can gain insights into the successful strategies used by pharmaceutical companies so far to bring innovative drugs to the market. Many challenges will have to be faced in the next decade to bring more efficient and affordable antibody-based drugs to the clinic. Here, we discuss strategies to select the best therapeutic antigen targets, to optimize the structure of IgG antibodies and to design related or new structures with additional functions.

Strategies and challenges for the next generation of therapeutic antibodies

Alternative molecular formats and therapeutic applications for bispecific antibodies.

Control of Metastasis by NK Cells

Monoclonal antibodies are widely used for the treatment of cancer, inflammatory and infectious diseases and other disorders. Most of the marketed antibodies are monospecific and therefore capable of interacting and interfering with a single target. However, complex diseases are often multifactorial in nature, and involve redundant or synergistic action of disease mediators or upregulation of different receptors, including crosstalk between their signaling networks. Consequently, blockade of multiple, different pathological factors and pathways may result in improved therapeutic efficacy. This result can be achieved by combining different drugs, or use of the dual targeting strategies applying bispecific antibodies that have emerged as an alternative to combination therapy. This review discusses the various dual targeting strategies for which bispecific antibodies have been developed and provides an overview of the established bispecific antibody formats.

https://www.tandfonline.com/doi/pdf/10.4161/mabs.4.2.19000

Dual targeting strategies with bispecific antibodies

BACKGROUND:
Peritoneal carcinomatosis (PC) from nonovarian malignancies long has been regarded as a terminal disease. Over the past decade, new locoregional therapeutic approaches combining cytoreductive surgery with perioperative intraperitoneal chemotherapy (PIC) have evolved that have demonstrated improved survival.

METHODS:
A retrospective, multicenter cohort study was performed in French-speaking institutions to evaluate toxicity and principal prognostic factors after cytoreductive surgery and PIC (hyperthermic intraperitoneal chemotherapy [HIPEC] and/or early postoperative intraperitoneal chemotherapy [EPIC]) for PC from nongynecologic malignancies.

RESULTS:
The study included 1290 patients from 25 institutions who underwent 1344 procedures between February 1989 and December 2007. HIPEC was performed in 1154 procedures. The principal origins of PC were colorectal adenocarcinoma (N = 523), pseudomyxoma peritonei (N = 301), gastric adenocarcinoma (N = 159), peritoneal mesothelioma (N = 88), and appendiceal adenocarcinoma (N = 50). The overall morbidity and mortality rates were 33.6% and 4.1%, respectively. In multivariate analysis, patient age, the extent of PC, and institutional experience had a significant influence on toxicity. The overall median survival was 34 months; and the median survival was 30 months for patients with colorectal PC, not reached for patients with pseudomyxoma peritonei, 9 months for patients with gastric PC, 41 months for patients with peritoneal mesothelioma, and 77 months for patients with PC from appendiceal adenocarcinoma. Independent prognostic indicators in multivariate analysis were institution, origin of PC, completeness of cytoreductive surgery, extent of carcinomatosis, and lymph node involvement.

CONCLUSIONS:
A therapeutic approach that combined cytoreductive surgery with PIC was able to achieve long-term survival in a selected group of patients who had PC of nonovarian origin and had acceptable morbidity and mortality. The current results indicated that this treatment should be centralized to institutions with expertise in the management of PC. Cancer 2010. © 2010 American Cancer Society.

Toward curative treatment of peritoneal carcinomatosis from nonovarian origin by cytoreductive surgery combined with perioperative intraperitoneal chemotherapy

Development and approval of the trifunctional antibody catumaxomab (anti-EpCAM x anti-CD3) as a targeted cancer immunotherapy.

Catumaxomab, a monoclonal bispecific trifunctional antibody, was approved in the European Union in April 2009 for the intraperitoneal treatment of patients with malignant ascites. The marketing authorization holder Fresenius Biotech GmbH developed catumaxomab (Removab(®)) together with its partner TRION Pharma GmbH, Germany. It is the first substance worldwide with a regulatory label for the treatment of malignant ascites due to epithelial carcinomas. Since the peritoneum is of mesothelial origin and therefore lacks EpCAM expression, the intraperitoneal administration of catumaxomab is an attractive targeted immunotherapeutic approach. Catumaxomab is able to destroy EpCAM positive tumor cells in the peritoneal cavity known as the main cause of malignant ascites. In addition, catumaxomab is a potential therapeutic option for several primary tumors since the EpCAM molecule is expressed on the majority of epithelial carcinomas. This review focuses on the clinical development of catumaxomab and indicates future directions.

https://www.tandfonline.com/doi/pdf/10.4161/mabs.2.2.11221

Catumaxomab: clinical development and future directions.

The trifunctional antibody catumaxomab is a targeted immunotherapy for the intraperitoneal treatment of malignant ascites. In a Phase II/III trial in cancer patients (n = 258) with malignant ascites, catumaxomab showed a clear clinical benefit vs. paracentesis and had an acceptable safety profile. Human antimouse antibodies (HAMAs), which could be associated with beneficial humoral effects and prolonged survival, may develop against catumaxomab as it is a mouse/rat antibody. This post hoc analysis investigated whether there was a correlation between the detection of HAMAs 8 days after the fourth catumaxomab infusion and clinical outcome. HAMA-positive and HAMA-negative patients in the catumaxomab group and patients in the control group were analyzed separately for all three clinical outcome measures (puncture-free survival, time to next puncture and overall survival) and compared to each other. There was a strong correlation between humoral response and clinical outcome: patients who developed HAMAs after catumaxomab showed significant improvement in all three clinical outcome measures vs. HAMA-negative patients. In the overall population in HAMA-positive vs. HAMA-negative patients, median puncture-free survival was 64 vs. 27 days (p < 0.0001; HR 0.330), median time to next therapeutic puncture was 104 vs. 46 days (p = 0.0002; HR 0.307) and median overall survival was 129 vs. 64 days (p = 0.0003; HR 0.433). Similar differences between HAMA-positive and HAMA-negative patients were seen in the ovarian, nonovarian and gastric cancer subgroups. In conclusion, HAMA development may be a biomarker for catumaxomab response and patients who developed HAMAs sooner derived greater benefit from catumaxomab treatment.

Humoral response to catumaxomab correlates with clinical outcome: Results of the pivotal phase II/III study in patients with malignant ascites

Background: Patients with gastric cancer benefit from perioperative chemotherapy, however, treatment is toxic and many patients will relapse. The trifunctional antibody catumaxomab targets EpCAM on...

/pdf/the-trifunctional-antibody-catumaxomab-amplifies-and-shapes-leupk46qxq.pdf

The trifunctional antibody catumaxomab amplifies and shapes tumor-specific immunity when applied to gastric cancer patients in the adjuvant setting.

Purpose: We report the role of relative lymphocyte count (RLC) as a potential biomarker with prognostic impact for catumaxomab efficacy and overall survival (OS) based on a post hoc analysis of the pivotal phase II/III study of intraperitoneal catumaxomab treatment of malignant ascites.

Experimental Design: The impact of treatment and RLC on OS was evaluated using multivariate Cox models. Kaplan–Meier and log-rank tests were used for group comparisons. Survival analyses were performed on the safety population [patients with paracentesis plus ≥1 dose of catumaxomab ( n = 157) and paracentesis alone ( n = 88)]. Determination of the optimal cutoff value for RLC was based on five optimality criteria.

Results: OS was significantly longer with catumaxomab versus paracentesis alone ( P = 0.0219). The 6-month OS rate with catumaxomab was 28.9% versus 6.7% with paracentesis alone. RLC had a positive impact on OS and was an independent prognostic factor ( P 13% ( n = 159: catumaxomab, 100 and control, 59), catumaxomab was associated with a favorable effect on OS versus paracentesis alone ( P = 0.0072), with a median/mean OS benefit of 41/131 days and an increased 6-month survival rate of 37.0% versus 5.2%, respectively. In patients with RLC ≤ 13% at screening ( n = 74: catumaxomab, 50 and control, 24), the median (mean) OS difference between the catumaxomab and the control group was 3 (16) days, respectively ( P = 0.2561).

Conclusions: OS was significantly improved after catumaxomab treatment in patients with malignant ascites. An RLC > 13% at baseline was a significant prognostic biomarker. Clin Cancer Res; 20(12); 3348–57. ©2014 AACR .

https://clincancerres.aacrjournals.org/content/clincanres/20/12/3348.full.pdf

The Role of Relative Lymphocyte Count as a Biomarker for the Effect of Catumaxomab on Survival in Malignant Ascites Patients: Results from a Phase II/III Study

D. Seimetz

Papers

Development and approval of the trifunctional antibody catumaxomab (anti-EpCAM x anti-CD3) as a targeted cancer immunotherapy.

Catumaxomab: clinical development and future directions.

Humoral response to catumaxomab correlates with clinical outcome: Results of the pivotal phase II/III study in patients with malignant ascites

The trifunctional antibody catumaxomab amplifies and shapes tumor-specific immunity when applied to gastric cancer patients in the adjuvant setting.

The Role of Relative Lymphocyte Count as a Biomarker for the Effect of Catumaxomab on Survival in Malignant Ascites Patients: Results from a Phase II/III Study