Nimotuzumab: beyond the EGFR signaling cascade inhibition.

One of the most known oncogenes is the epidermal growth factor receptor (EGFR) family. It activates multiple signaling cascades that promote carcinogenesis and immune evasion. Therefore, these molecules have been extensively targeted in cancer immunotherapy. Beyond EGFR signaling cascade inhibition, some of these agents are able to induce T-cell activation, transforming a passive therapy into a vaccine-like effect. Nimotuzumab is an IgG1 humanized monoclonal antibody directed against the extracellular domain of the EGFR blocking the binding to its ligands. It possesses unique pharmacodynamic properties, which allow treating patients for long-term periods and with very low toxicity. Based on its clinical effect, nimotuzumab has been approved in Cuba and abroad for the treatment of different epithelial tumors. Recently, new potential mechanisms of action of nimotuzumab involving the activation of the innate and adaptive immune response have been reported. This review summarizes the main properties of nimotuzumab in comparison with other EGFR-specific monoclonal antibodies, highlighting its capacity to activate an effective immune response. In addition, differential clinical effects of this antibody and ongoing clinical trials to deeply characterize the biomarkers of clinical benefit are shown.

Bivalent binding by intermediate affinity of nimotuzumab: a contribution to explain antibody clinical profile.

Nimotuzumab is an EGFR-targeting antibody that has demonstrated encouraging clinical results in the absence of severe side-effects observed with other approved anti-EGFR antibodies. We investigated whether different clinical behavior of nimotuzumab is related to its bivalent/monovalent binding profile. Binding properties of nimotuzumab and cetuximab, the most development of anti-EGFR antibodies, were studied in vitro using chip surfaces and cells with varying EGFR expression levels. Experimental observations demonstrated that in contrast to cetuximab, the intrinsic properties of nimotuzumab required bivalent binding for stable attachment to the cellular surface, leading to nimotuzumab selectively binding to cells that express moderate to high EGFR expression levels. At these conditions, both antibodies bound bivalently, and accumulated to similar degrees. When EGFR density is low, nimotuzumab monovalent interaction was transient, whereas cetuximab continued to interact strongly with the receptors. We compared the in vitro anti-tumor efficacy of nimotuzumab and cetuximab. Cetuximab decreased the cell viability and induced apoptosis for all the tested cell lines, effects which did not depend on EGFR expression level. In contrast, nimotuzumab also provoked significant anti-cellular effects, but its anti-tumor capacity decreased together with EGFR expression level. Cetuximab Fab fragment was able to impact tumor cell survival, whereas nimotuzumab fragment totally lost this effect. Tumor-xenograft experiments using cells with a high EGFR expression revealed similar tumor growth inhibiting effects for both antibodies. This study suggests an explanation for nimotuzumab clinical profile, whereby anti-tumor activity is obtained in absence of severe toxicities due to its properties of bivalent binding to EGFR.

Nimotuzumab plus radiotherapy for unresectable squamous-cell carcinoma of the head and neck.

The prognosis of patients with advanced head and neck cancer remain dismal. For this tumor type, elevated levels of EGFR are associated with a shorter disease free survival and time to treatment failure, reflecting a more aggressive phenotype. Nimotuzumab is a humanized monoclonal antibody that recognizes domain III of the extracellular region of the EGFR, within an area that overlaps with both the surface patch recognized by cetuximab and the binding site for EGF. In order to assess the efficacy of nimotuzumab in combination with radiotherapy, a controlled, double blind, randomized clinical trial was conducted in 106 advanced squamous cell carcinoma of the head and neck patients, mostly, unfit for chemoradiotherapy. Control patients received a placebo and radiotherapy. Treatment was safe and the most frequent adverse events consisted on grade I or II asthenia, fever, headache and chills. No skin rash was detected. A significant complete response rate improvement was found in the group of patients treated with nimotuzumab as compared to the placebo. In the intent to treat analysis, a trend towards survival benefit for nimotuzumab treated subjects was found. The survival benefit became significant when applying the Harrington-Fleming test, a weighted log-rank that underscores the detection of differences deferred on time. In addition, a preliminary biomarker investigation showed a significant survival improvement for nimotuzumab treated patients as compared to controls for subjects with EGFR positive tumors. All patients showed a quality of life improvement and a reduction of the general and specific symptoms of the disease.

Pharmacodynamic trial of nimotuzumab in unresectable squamous cell carcinoma of the head and neck: a SENDO Foundation study.

PURPOSE: To assess the pharmacodynamic effects of nimotuzumab, an anti-epidermal growth factor receptor (EGFR) monoclonal antibody with intermediate affinity for the receptor, in skin and tumor tissues from head and neck cancer patients. EXPERIMENTAL DESIGN: Pharmacodynamic study in patients with advanced squamous cell carcinoma of the head and neck, unsuitable for chemoradiotherapy, enrolled in a single-center trial. Patients received 8 weekly infusions of nimotuzumab. The first nimotuzumab infusion was administered 1 week before starting radiation, whereas the remaining doses were administered concomitantly with irradiation. Paired biopsies were taken from skin and primary tumors, before (pretherapy) and 1 week (on single-agent therapy) after first infusion. Immunohistochemistry was conducted to assay the effects of nimotuzumab on total and phosphorylated EGFR, phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK1/2), p-AKT, and proliferation (Ki-67). RESULTS: Nimotuzumab was well tolerated and there was no evidence of skin rash. Objective response was achieved in 9 of 10 patients. The pharmacodynamic assays showed inhibition of p-EGFR in both skin and tumor (P = 0.042 in skin and P = 0.034 in tumor). No significant changes in p-ERK1/2, p-AKT, or Ki-67 were detected in skin. In addition, lymphocytic infiltrates, folliculitis, or perifolliculitis were not observed. In tumor samples, there was an upregulation of p-AKT (P = 0.043), a reduction in proliferation index (P = 0.012), and a nonsignificant trend toward a decrease of p-ERK1/2 (P = 0.091). CONCLUSIONS: The pharmacodynamic data confirmed the ability of nimotuzumab to decrease EGFR phosphorylation. Downstream effects were observed in tumor cells but not in skin, a finding that may help to explain the lack of skin rash in patients treated with nimotuzumab.

Clinical experience with nimotuzumab in cuban pediatric patients with brain tumors, 2005 to 2007.

Introduction Nimotuzumab, developed in Cuba, is a humanized monoclonal antibody that targets the epidermal growth factor receptor (EGFR). It has been evaluated in malignant brain tumors in adults and children, and shown to be therapeutically safe and effective in terms of increased survival and improved quality of life. Objective Describe nimotuzumab's safety profile and clinical benefits in terms of disease control and survival in pediatric patients with progressive or recurrent primary brain tumors who were included in an expanded access program. Methods An open, prospective clinical study was designed. Between December 2005 and December 2007, 22 patients were included, all of whom had an histological and/or radiological diagnosis of progressive or recurrent primary brain tumor, classified as high-grade malignant glioblastoma (n=6), diffuse brain stem glioma (n=6), ependymoblastoma (n=5), low-grade glioma (n=4), or thalamic tumor (n=1); life expectancy of at least 4 weeks; and a Karnofsky or Lansky Performance Status score of ≥50. Nimotuzumab was administered on a 100 mg weekly intravenous infusion schedule for 6 to 8 weeks, followed by a bi-weekly maintenance phase, as long as there was no deterioration in the patient's functional capacity. Therapeutic protocols were followed for administration as monotherapy or in combination with chemotherapy and/or radiotherapy. All patients received clinical and imaging follow-up. Results Nimotuzumab was well tolerated in all therapeutic modalities, even with prolonged exposure. A minority of patients reported slight or moderate adverse events, such as vomiting, mucositis and chills, as classified by the Common Terminology Criteria for Adverse Events (CTCAE). The disease was controlled in 64% (14/22) of patients; 6-month and 1-year survival rates were 82% and 64%, respectively; average survival was 20.3 months and median survival, 19 months. Recovery of neurological functions and improvement in general status were notable in patients who attained control of the disease. Conclusions As used in this study, nimotuzumab demonstrated a broad safety profile, making it acceptable for chronic use, and implied clinical benefits in terms of increased survival and improved functional status in these patients, compared to findings described in the literature. These results indicate further studies of this product are warranted.

Pharmacological evaluation of humanized anti-epidermal growth factor receptor, monoclonal antibody h-R3, in patients with advanced epithelial-derived cancer.

Epidermal growth factor receptor (EGFR) overexpression has been detected in many tumors of epithelial origin, and it is often associated with tumor growth advantages and poor prognosis. h-R3 is a genetically engineered humanized antibody (mAb) that recognizes an epitope located in the extracellular domain of human EGFR. The antibody exhibited potent in vitro and in vivo antitumor effect on EGFR overexpressing cell lines. To study safety, pharmacokinetics, and biodistribution, 12 patients with advanced epithelial-derived tumors received single intravenous infusion of h-R3 at four dose levels. Safety evaluation was made according to World Health Organization toxicity criteria. For biodistribution, 3 mg of the total dose were labeled with Technetium and then pooled with the rest of the dose. Anterior and posterior whole-body images were acquired using a gamma camera. Blood samples were taken for pharmacokinetics, antiidiotypic response, and for soluble EGFR detection. After hR3 administration, no evidence of severe toxicity was observed. Secondary reactions were mild and moderate and mainly consisted of tremors, fever, and vomiting. No anaphylactic or skin reactions were detected. Qualitative analysis of whole-body images showed that the liver had the highest mAb uptake. Pharmacokinetic analysis revealed that elimination half-lives and the AUC increased linearly with dose, while total body clearance decreased when increasing doses of h-R3. No relation between shed EGFR and mAb clearance was found. No antiidiotypic response against h-R3 was detected. Several phase II trials are now underway to evaluate the efficacy of h-R3 in the treatment of advanced cancer patients.