IMC-C225, an anti-epidermal growth factor receptor monoclonal antibody for treatment of head and neck cancer

IMC-C225, an Anti-Epidermal Growth Factor Receptor Monoclonal Antibody for Treatment of Head and Neck Cancer Roy S. Herbst and Waun Ki Hong

From the Department of Thoracic/Head and Neck Medical Oncology, The University of Texas M. D. Anderson Cancer Center, Houston, TX. Dr Herbst has received research grant support from ImClone Systems Incorporated. Dr Hong is a consultant with ImClone Systems Incorporated. Address reprint requests to Roy S. Herbst, MD, PhD, The University of Texas M. D. Anderson Cancer Center, 1515 Holcombe Blvd, Box 432, Houston, TX 77030. Copyright 2002, Elsevier Science (USA). All rights reserved. 0093-7754/02/2905-1404$35.00/0 doi:10.1053/sonc.2002.35644

caused by this disease in the United States in 2001.1 Two thirds of the patients are initially diagnosed with local or regionally advanced disease, and fewer than 30% of these patients are cured.2 Standard treatment includes surgery, radiation, chemoradiation, or a combination of these approaches. Although chemotherapy is commonly reserved for recurrent or metastatic disease, which is largely incurable,3,4 there is accumulating evidence to support the use of concurrent chemoradiation in the definitive treatment setting. Despite advances in treatment, many patients will die of locally or regionally persistent or recurrent disease.5 While numerous investigational approaches such as chemotherapy combined with surgery or radiation, induction or adjuvant chemotherapy, or variations in radiation fractionation schedules have been studied, there has been modest improvement in survival rates because the majority of patients continue to experience locoregional disease recurrence.2 One of the characteristics contributing to the high rate of locoregional disease recurrence is the rapid proliferation of SCCHN. Head and neck carcinomas, one of the most rapidly proliferating solid tumors, show a median in vivo tumor doubling time of 3 to 5 days.6 Rapid proliferation of surviving tumor cells during prolonged radiation therapy to the head and neck contributes to reduced local control7; therefore, the role of growth factors that influence the proliferation and progression of malignancy has become increasingly important and better understood over the past decade. Modulation of growth factors and their effects offers a new strategy in the effort to improve tumor control and survival rates for patients with head and neck carcinomas. The significance of the epidermal growth factor receptor (EGFR) in the development and progression of epithelial malignancies is increasingly well understood. There are many current approaches to EGFR blockade as an anticancer treatment strategy because EGFR inhibition can be achieved at several levels.8-11 Antitumor activity has been shown by anti-EGFR monoclonal antibodies (mAb), which bind to extracellular domains of the

18

Seminars in Oncology, Vol 29, No 5, Suppl 14 (October), 2002: pp 18-30

Squamous cell carcinoma of the head and neck remains a clinical challenge because of the high rate of locoregional disease recurrence. The importance of the epidermal growth factor receptor (EGFR) in the development and progression of many solid tumors, including squamous cell carcinoma of the head and neck, is well understood; increased expression is associated with enhanced tumor invasiveness, resistance to chemotherapy, and a lower patient survival rate. Several approaches have been developed to achieve EGFR blockade as an anticancer treatment strategy, including the anti-EGFR monoclonal antibody IMC-C225, which competitively binds to the extracellular receptor site and prevents binding by the natural EGFR ligands EGF and transforming growth factor–alpha. Preclinical studies to evaluate IMC-225 in human cancer cell lines in vitro and human tumor xenografts in vivo have shown its potent antitumor activity. Clinical efficacy of IMC-C225 appears to involve multiple mechanisms, including inhibition of cell cycle progression, induction of apoptosis, inhibition of angiogenesis, inhibition of metastasis, and enhancement of the response to chemotherapy and radiation therapy. Phase I studies of IMC-C225 combined with chemotherapy or radiation showed promising response rates in patients with recurrent or refractory squamous cell carcinoma of the head and neck. Phase II and III trials to examine the efficacy and safety of these combinations are currently underway. To date, IMC-C225 has been well tolerated, with skin rashes and allergic reactions being the most clinically important adverse events reported. IMC-C225 displays dose-dependent elimination characteristics and a half-life of approximately 7 days. Current recommendations for dosing include a 400 mg/m2 loading dose, followed by weekly infusions at 250 mg/m2. Semin Oncol 29 (suppl 14):18-30. Copyright 2002, Elsevier Science (USA). All rights reserved.

A

PPROXIMATELY 40,000 cases of squamous cell carcinoma of the head and neck (SCCHN) were diagnosed and 12,000 deaths were

IMC-225 IN THE TREATMENT OF HEAD & NECK CANCER

19

Table 1. Approaches to Epidermal Growth Factor Receptor Inhibition Approach Anti-EGFR antibody12-15

Tyrosine kinase inhibitor11-16 Ligand conjugate, immunoconjugate17-19

Antisense oligonucleotide20-22

Effect Binds to EGFR extracellularly, blocks binding and subsequent effects of endogenous ligands Works intracellularly to inhibit tyrosine kinase signaling pathways Binds extracellularly to the EGFR and delivers a toxic compound after internalization of the ligand-toxin conjugate Prevents the translation of mRNA, inhibiting protein synthesis

receptor and prevent binding of the natural EGFR ligands, EGF and transforming growth factor– alpha (TGF-␣)12-15; by tyrosine kinase inhibitors, which act intracellularly to inhibit tyrosine kinase signaling pathways11-16; by ligand conjugates, in which an EGFR ligand is conjugated to a toxin (eg, ricin, Pseudomonas exotoxin)17,18; by immunoconjugates, in which an anti-EGFR antibody is conjugated to a toxin19; and by antisense therapy that inhibits protein production and expression with DNA or RNA oligonucleotides targeted to the EGFR (Table 1).20-22

Fig 1. Schematic of the EGFR and its role in signal transduction and tumor progression. Reprinted with permission.10

Examples IMC-C225, ABX-EGF, ICR 62, EMD 55900

OSI-774, ZD1839, PKI-116, CI-1033 EGF-ricin, EGF-genistein, TGF-␣Pseudomonas exotoxin A (ETA), heparin-binding protein (HB)-EGF-toxin fusion protein

CORRELATION BETWEEN EPIDERMAL GROWTH FACTOR RECEPTOR AND MALIGNANCY

The EGFR is a 170-kd transmembrane protein comprised of a single polypeptide chain of 1,186 amino acid residues.23 The EGFR is composed of three domains: an extracellular ligand-binding domain, a transmembrane lipophilic segment, and an intracellular protein tyrosine kinase domain (Fig 1).24 The glycosylated extracellular domain that expresses the ligand binding site is anchored

20

to the cellular membrane via a single hydrophobic membrane composed of only 23 hydrophobic amino acids, which, in turn, is attached to the intracellular portion that possesses intrinsic tyrosine kinase activity.23,25 There are a variety of endogenous ligands for the EGFR including EGF, TGF-␣, heparin-binding EGF, amphiregulin, and betacellulin.26 TGF-␣ is thought to be the most important ligand regulating the activity of EGFR. On ligand binding to the EGFR, the ligand-receptor complex undergoes dimerization and internalization and is no longer available on the cell surface.27 Epidermal growth factor receptor dimerization activates the intracellular protein kinase via autophosphorylation, which, in turn, stimulates signal transduction involving a complex network of interrelated pathways regulating a variety of mitogenic mechanisms involved in cell proliferation, differentiation, and survival.28,29 Binding of both EGF and TGF-␣ results in EGFR downregulation with the loss of approximately 80% of receptors within 2 hours, followed by normal EGFR expression within 9 hours after removal of the ligand.30 Numerous studies have shown that EGFR activity contributes to the development and progression of malignancy. The EGFR is important in regulating cell survival and apoptosis, angiogenesis, cell motility, and metastasis. Rodeck et al31 showed that EGFR pathways are important in promoting cell cycle progression and survival of normal human keratinocytes. In another separate study, Gibson et al32 showed that EGF stimulation of three different cell lines (T47D and MCF7 breast adenocarcinoma cells and HEK293 embryonic kidney epithelial cells) protected the cells by significantly reducing Fas-induced apoptosis. Other investigators have shown that EGFR activation is associated with significant upregulation of secretion of vascular endothelial cell growth factor (VEGF), an important stimulator of tumor angiogenesis.33 Moreover, in vitro treatment with IMC-C225 (Erbitux, cetuximab; ImClone Systems Incorporated, New York, NY, and Bristol-Myers Squibb Company, Princeton, NJ) antibody inhibited VEGF production and reduced the average number of tumor blood vessels.33,34 In addition, EGF may promote tumor cell motility and metastatic potential by increasing the cellular expression of matrix metalloproteinases.35-37 These effects have been inhibited in vitro by

HERBST AND HONG

blocking EGFR signaling with the anti-EGFR mAb IMC-C225.38,39 Epidermal growth factor receptor is distributed randomly on the surface of normal cells, excluding hematopoietic cells and cells of epidermal origin.25,40,41 In addition to expression on normal cells, EGFR has been observed in a variety of human solid tumors including glioma and colon, head and neck, pancreatic, non–small cell lung, breast, renal, ovarian, and bladder carcinomas.26 Studies have shown that the majority of SCCHN (80% to 100%) express EGFR.26,42-45 Elevated EGFR expression may be the result of a variety of mechanisms including amplification of the EGFR gene, mutations of EGFR mRNA transcription or translation, or EGFR mutations resulting in constitutively active tyrosine kinase. In the case of head and neck carcinoma, it is likely that elevated EGFR gene transcription is responsible for most of the EGFR expression.43 There are various methods by which levels of EGFR expression can be measured; however, immunohistochemistry has been the primary method of EGFR detection because it is reliable, fast, and simple (Fig 2). Given the increased expression of EGFR in tumors, numerous studies have investigated the prognostic significance of such expression. While there has been controversy surrounding the implications of this expression, numerous studies in a variety of tumor types have shown that EGFR expression is associated with a poorer prognosis; that is, greater risk of invasive or metastatic disease, resistance to chemotherapy, and shorter survival time.46-50 In a study to determine the prognostic value of EGFR expression in head and neck carcinomas, Grandis et al51 determined that EGFR protein levels significantly predict a shorter disease-free survival time and shorter cause-specific overall survival time. Maurizi et al52 showed that elevated EGFR levels in laryngeal squamous cell carcinomas (SCC) were correlated significantly with diminished overall and relapse-free survival times. In addition, multivariate analysis showed that EGFR expression is an independent prognostic variable. Elevated EGFR levels have also been correlated significantly with increased tumor size and advanced tumor stage.53,54 Ke et al55 showed that poorly differentiated head and neck tumors had higher levels of EGFR expression than were found in well-differentiated tumors. Finally, Shin

IMC-225 IN THE TREATMENT OF HEAD & NECK CANCER

21

Fig 2. Epidermal growth factor receptor staining by immunohistochemistry in head and neck and colorectal cancers. Panels A and C represent controls. Panels B and D represent EGFR staining. Panels A and B are squamous cell head and neck cancer. Panels C and D are colorectal cancer. Data on file, Imclone Systems Incorporated, Somerville, NJ. Our thanks to DAKO Corporation (Carpinteria, CA) for providing these images.

et al42 evaluated EGFR expression in premalignant head and neck lesions to ascertain whether or not EGFR expression might be a useful biomarker for tumorigenesis. This study showed that histologically normal epithelium adjacent to tumors demonstrated a two-fold higher relative staining intensity for EGFR than did normal control epithelium. Furthermore, in a model representative of tumorigenesis, EGFR relative staining intensity increased significantly when control tissues were compared with normal epithelium adjacent to tumors and with hyperplastic and dysplastic tissues. Epidermal growth factor receptor relative staining intensity also increased significantly as disease progressed from dysplasia to SCC. These results led these investigators to conclude that changes in EGFR expression rates occur in two stages. Initially, EGFR expression is upregulated in histologically normal epithelium adjacent to a tumor and in hyperplastic and dysplastic premalignant lesions, and then a notable increase in EGFR ex-

pression occurs as dysplasia becomes SCC. These results indicate that EGFR expression may be a viable biomarker for patients with head and neck carcinoma. Thus, given the role of the EGFR pathways in the development and progression of malignancy, the high level of EGFR expression in head and neck carcinoma, and the poor prognosis associated with such expression, EGFR blockade offers a promising therapeutic strategy for cancer patients. The anti-EGFR mAb IMC-C225 has had extensive preclinical evaluation and is currently being tested in phase II and III trials in a variety of tumor types, including SCCHN. PHARMACOKINETIC AND PHARMACODYNAMIC PROPERTIES OF IMC-C225

The murine anti-EGFR mAb 225 (M225) has been well studied in preclinical models and has been shown to have notable antitumor activity.56

22

To overcome the inherent difficulties in using murine mAbs for widespread therapeutic benefit, IMC-C225, a chimeric mAb, was developed. As compared with murine mAbs, chimeric mAbs exhibit prolonged circulation times, less immunogenicity, and enhanced antitumor activity.57,58 With IMC-C225, the variable regions of M225 have been chimerized to the constant regions of human IgG1. In a comparison of the in vivo activity of M225 and IMC-C225, IMC-C225 was more effective at inducing complete tumor remission in A431 xenografts than was M225.59 IMC-C225 demonstrates specificity for the EGFR, binds competitively with the natural ligands to the EGFR, and undergoes receptor dimerization, which, unlike TGF-␣ binding, prevents EGFR autophosphorylation and thus does not allow activation of the tyrosine kinase-mediated signaling cascade.60-63 A study by Sunada et al64 provides evidence supporting the theory that IMC-C225 promotes EGFR internalization, which ultimately decreases the number of free EGFRs on the cell surface. Baselga et al65 studied the pharmacokinetic properties of IMC-C225 in patients with head and neck or non–small cell lung cancer. Data from both single- and multiple-dose studies showed that the systemic clearance of IMC-C225 decreased with increasing doses (20, 50, and 100 mg/m2), while the volume of distribution at steady state remained relatively unchanged, approximating the plasma volume. These data suggest that IMCC225 is saturable in a dose-dependent way. Further analysis showed no difference in clearance values with doses between 200 mg/m2 and 400 mg/m2, indicating complete saturation of IMC-C225 clearance within this dose range. Concentration-versus-time data for the 400 mg/m2 dose show a linear relationship over the first 96 hours following IMC-C225 infusion, which is consistent with zero-order elimination. An elimination half-life of 7 days was calculated for both the 200 mg/m2 and 400 mg/m2 dose levels. A multipledose trial showed no change in the clearance of IMC-C225 over time or when it was coadministered with cisplatin. Based on pharmacokinetic modeling, the currently recommended dose of IMC-C225 is an initial loading dose of 400 mg/m2, followed by weekly maintenance infusions of 250 mg/m2.66 The antitumor efficacy of IMC-C225 results

HERBST AND HONG

Table 2. IMC-C225: Proposed Mechanisms of Action ● Inhibits cell cycle progression ● Promotes apoptosis ● Exhibits antiangiogenic effects ● Inhibits metastasis ● Displays immunologic effects

from multiple mechanisms, including inhibition of cell cycle progression and promotion of apoptosis, antiangiogenic activity, inhibition of metastasis, and potential enhancement of immunologic activity (antibody-dependent cellular toxicity) (Table 2). These mechanisms of action, while important and demonstrated in vitro, have yet to be fully validated clinically. Huang et al67 observed that compared with controls, IMC-C225–treated SCCHN cells stayed in the G0/G1 phase of the cell cycle, and fewer cells progressed to S phase. In this early study and others, IMC-C225 exposure resulted in the increased expression of the G1 cyclin– dependent kinase inhibitor, p27KIP1, as well as accumulation of the hypophosphorylated form of the retinoblastoma protein.67-69 Phosphorylation of retinoblastoma protein is necessary for the release of the transcription factor E2F, which, in turn, is needed for the G1-to-S–phase transition. In addition to undergoing G0/G1 cell cycle arrest, a human colorectal cancer cell line (DiFi) exhibited apoptosis when cultured with IMCC225 in concentrations adequate to saturate the EGFR.70-72 Although the responsible mechanisms remain unclear, it has been suggested that EGFR blockade-induced cell death may be influenced by activation of the caspase cascade. Caspases are a family of proteinases integral to the proteolytic processes involved in cell death.72 Additional work suggests that the anti-EGFR mAb IMCC225 stimulates increased production of Bax, thereby altering the Bax:Bcl-2 ratio within the cell and inducing apoptosis.67,71 A number of studies have documented the antiangiogenic activity of IMC-C225. Petit et al33 observed that IMC-C225–treated A431 human epidermoid carcinoma cells exhibited a dose-dependent inhibition of VEGF production in vitro. Furthermore, when IMC-C225 was applied to established A431 tumors in vivo, there was a suppression of VEGF expression in addition to a two-

IMC-225 IN THE TREATMENT OF HEAD & NECK CANCER

23

Fig 3. IMC-C225 and cytotoxic therapies interact to enhance antitumor activity.

fold reduction in the number of tumor blood vessels compared with control tumors. Confirmation of IMC-C225’s antiangiogenic activity was demonstrated in human SCC xenografts derived from patients with head and neck cancer that showed downregulation of VEGF and factor VIII expression.73 IMC-C225 exposure in the human transitional cell carcinoma cell line 253J B-V was associated with dose-dependent downregulation of VEGF, interleukin-8, and basic fibroblast growth factor both in vitro and in vivo.34 Additionally, microvessel density was lower in the IMC-C225– treated tumors than in control tumors. Finally, L3.6pl human pancreatic cell lines and orthotopic tumors treated with IMC-C225 showed diminished production of VEGF and interleukin-8 followed by involution of tumor-induced neovascularity and decreased microvessel density.74 A number of studies have suggested that IMC-C225 may diminish the metastatic potential of tumors. When orthotopic transitional cell carcinoma tumors were treated with IMC-C225, tu-

mor growth and metastasis were inhibited and matrix metalloproteinase-9 activity decreased.38 Additional studies by Bruns et al74 and Perrotte et al34 have shown that IMC-C225–treated animals with orthotopic bladder and pancreatic xenografts had fewer lymph node, liver, or lung metastases than did control animals. In addition to the antitumor effects of IMC-C225 delivered as a single agent, there is evidence to suggest that IMC-C225 combined with radiation or chemotherapy produces enhanced antitumor activity. While the precise mechanism for enhanced antitumor activity is not clear, several have been proposed (Fig 3). With regard to radiation therapy, studies by Harari and Huang75 used in vitro and in vivo models of SCCHN to show the capacity of IMC-C225 to promote radiationinduced apoptosis, inhibit radiation-induced damage repair, enhance radiosensitivity, and inhibit angiogenesis. It has been hypothesized that inhibition of the EGFR pathways may enhance the antitumor effects of chemotherapy by depriving

24

HERBST AND HONG

Table 3. Enhanced Antitumor Activity: Preclinical Findings Combination Therapy

Tumor Type

Antitumor Activity

mAb 225 and cisplatin80

A431 human epidermoid carcinoma

IMC-C225 and doxorubicin82

A431 human epidermoid carcinoma

IMC-C225 and doxorubicin14

DU145 and PC-3 prostatic carcinoma

mAb 225 and doxorubicin83

A431 human SCC and MDA-486 human breast adenocarcinoma

IMC-C225 and liposomal doxorubicin84 IMC-C225 and topotecan85

A431 human epidermoid carcinoma

IMC-C225 and gemcitabine74 IMC-C225 and 5-fluorouracil86

GEO human colon, OVCAR-3 human ovarian, ZR-75-1 human breast, and 1A9, PTX-10, and PTX-22 human ovarian cancers L3.6pl human pancreatic carcinoma BxPC-3 human pancreatic carcinoma

IMC-C225 and radiation75

SCCHN

IMC-C225 and radiation87 IMC-C225 and radiation88

U251 human glioma A431 human epidermoid carcinoma

IMC-C225 and radiation89

UM-SCC-6 human head and neck carcinoma A431 tumors

IMC-C225 and radiation90

cells of necessary growth factors.56 Cells damaged by chemotherapy generally arrest in the G2-M phases to undergo the repairs needed to continue through the cell cycle. Growth factors may be required for repair; thus, blockade of the EGFR prevents the signal transduction pathways necessary to sustain cellular viability. Studies of SCCHN and other cancers have established an association between tumor EGFR expression and poor response to radiation therapy.76,77 It is theorized that irradiated cells typically arrest in the G2-M phase to repair DNA damage before completing the cell cycle.78 By administering IMC-C225, which arrests cells in G1, increased killing of cells is observed, which may be because of simultaneous blockade at two cell cycle checkpoints.73

Enhanced inhibition of tumor cells in vitro and inhibition of growth of established xenografts in vivo Enhanced apoptosis, inhibition of proliferation, and decreased p53, retinoblastoma protein, and EGFR expression and activation Significant inhibition of xenografts and induction of remission Enhanced inhibition of growth in vitro and substantial increase in antitumor activity in vivo Significant inhibition of tumor growth and induction of tumor remission Enhanced inhibition of growth in vitro and regression of GEO tumors and prolonged survival in vivo Enhanced antitumor effects Enhanced antitumor effects and tumor regression Enhanced radiosensitivity and radiationinduced apoptosis in vitro and increased complete tumor regression in vivo Significant increase in survival time Enhanced inhibition of proliferation in vitro; and increased complete tumor regression, reduction in tumor size doubling time, and increased survival rate in vivo Enhanced radiation-induced growth inhibition Amplification of terminal differentiation and inhibition of angiogenesis

Numerous preclinical studies have shown enhanced antitumor activity when IMC-C225 is administered with chemotherapy or radiation therapy (Table 3). Studies examining the combinations of IMC-C225 and cisplatin,79,80 paclitaxel,81 doxorubicin,14,82-84 topotecan,85 gemcitabine,74 and 5-fluorouracil86 have shown significant inhibition of tumor cell growth, enhanced cytotoxic effect, and tumor regression in various human cancer xenografts. Similarly, the use of IMC-C225 plus radiation therapy in human epidermoid cancer xenografts67,73,75,87-90 resulted in increased tumor radiosensitivity, radiation-induced apoptosis, inhibition of angiogenesis, and ultimately, tumor regression and prolonged survival. These promising results have prompted phase I-III clinical trials of IMC-C225 alone and in

IMC-225 IN THE TREATMENT OF HEAD & NECK CANCER

25

Table 4. Phase II/III Trials to Evaluate the Efficacy of IMC-C225 Phase

Tumor Type

II II II II III III

Colorectal Pancreatic H&N H&N H&N H&N

Disease Characteristics Metastatic or recurrent disease refractory to irinotecan Advanced Metastatic or recurrent Locoregionally advanced Recurrent or metastatic

Treatment IMC-C225 and irinotecan* IMC-C225 and gemcitabine* IMC-C225 and cisplatin IMC-C225 and cisplatin and XRT XRT ⫾ IMC-C225 Cisplatin ⫾ IMC-C225

Abbreviations: H&N, head and neck; XRT, irradiation. * Study completed

combination with chemotherapy and radiation therapy. CLINICAL EFFICACY

The true activity of IMC-C225 as a single agent in the treatment of solid tumors remains unknown. A small-scale phase I study by Baselga and colleagues65 showed no response when IMC-C225 was used as a single agent. Clinically significant activity in advanced solid tumors is unlikely, although more extensive phase II studies are required. Because IMC-C225 showed synergy with chemotherapy in early clinical studies (those described here), such a combination was emphasized in the first efficacy trials. Phase I studies of IMC-C225 and cisplatin for refractory SCCHN showed promising biological activity.65,66,91 Preliminary data from Perez-Soler et al91 reported two minor responses in five patients receiving cisplatin plus IMC-C225 (100 mg/m2 weekly for 6 weeks). In a study by Baselga et al,65 weekly doses of IMC-C225 and cisplatin given to 22 patients with recurrent head and neck cancer produced a partial response in two patients and stable disease in an additional 11 patients after 4 weeks of therapy. These early responses were attributed to the use of higher doses (200 mg/m2 and 400 mg/m2 in cases of partial response) and the fact that optimal tumor activity may only be observed subsequent to achieving tumor receptor saturation and therapeutic serum concentrations. Nine of 13 patients (69%) receiving IMC-C225 doses of at least 50 mg/m2 experienced disease stabilization and completed 12 weeks of treatment. Shin et al66 conducted a phase I dose-escalation study of IMC-C225 in combination with cisplatin

in patients with recurrent SCCHN. Twelve patients received weekly IMC-C225 infusions of 250 mg/m2 (following a loading dose of 400 mg/m2 or 500 mg/m2) and cisplatin every 3 weeks. Of these 12 patients, responses could be evaluated in nine. Six patients showed an objective response (two complete, four partial), and three of these patients had prior exposure to cisplatin. Overall, the combined treatment was well tolerated, with fever, allergic reactions, and skin reactions (grade 3 or less) reported. Tissue biopsy samples taken prestudy, 24 hours after the first IMC-C225 treatment, and 24 hours before the third IMC-C225 treatment enabled the investigators to show pharmacodynamic evidence of receptor saturation and tumor inhibition.92 A phase I study of IMC-C225 (100 mg/m2 to 500 mg/m2 intravenous loading dose, followed by 100 mg/m2 to 250 mg/m2 weekly for 7 weeks) combined with once- or twice-daily radiation therapy was conducted to determine its efficacy and safety in 16 patients with locally advanced (unresectable) head and neck malignancies.93 In 13 of 15 cases (87%) a complete response was achieved, in contrast to the expected response rate of 31% to 46% associated with radiotherapy alone. The median duration of response to date is 13.9 months (range, 3 months to 27⫹ months), with 67% of patients currently progression free. Treatment was generally well tolerated. Based on these promising results observed in patients with typically poor response rates, phase II and III trials are ongoing (Table 4). Our focus is primarily on trials in refractory head and neck cancer to follow-up on the studies of Shin et al.92 Recurrent SCCHN that fails to respond to platinum-based therapy rarely responds to second-line

26

HERBST AND HONG

treatment (⬍ 5%), and patients in these circumstances do not live long (median survival ⬍ 3 months). We are currently conducting a study to explore the role of IMC-C225 plus cisplatin in these patients. Patients with recurrent SCCHN received two cycles of a regimen containing cisplatin (CDDP), and those patients with either progressive or stable disease go on to receive CDDP plus IMC-C225. Patients received a 400 mg/m2 loading dose of IMC-C225 followed by 250 mg/m2, weekly, plus intravenous CDDP at the same dose and schedule previously administered (either 100 mg/m2 for the paclitaxel regimen or 75 mg/m2 for the 5-fluorouracil regimen). In a preliminary analysis, 38 stable-disease patients were evaluated. In eight cases (21%), an objective response to therapy was shown (one complete response and seven partial responses), and in 22 patients (58%), stable disease was maintained. In an additional group of 22 patients with progressive disease following cisplatin, five patients (23%) achieved a partial response to therapy and six patients (27%) achieved disease stabilization.94 These preliminary data illustrate that IMC-C225 in combination with CDDP is well tolerated, and the response rate suggests that this combination of biologic and cytotoxic therapy has clinical activity. Certainly a more definitive conclusion awaits completion of this trial and final independent review of the radiographs. SAFETY AND TOLERABILITY

IMC-C225 has been administered alone and in combination with chemotherapy or with radiation therapy to more than 750 patients. Overall, it has been well tolerated and is not associated with serious adverse effects. In a review of clinical trials using IMC-C225 alone, the majority of adverse events were mild to moderate. Twelve percent were considered to be grade 3 or 4 in severity.95 The most clinically important adverse events reported were allergic reactions and acne-like rashes. Of 189 patients studied, eight (4%) experienced grades 3 and 4 allergic reactions. In three cases, these were grade 4 anaphylactic reactions (Fig 4). All patients recovered without sequel after standard treatment. Patients who have experienced low-grade allergic reactions have been able to receive subsequent IMC-C225 infusions with prophylactic antihistamine therapy and a slower infusion rate. In a separate study, sera samples were

Fig 4. Incidence and severity of allergic reactions related to IMC-C225 treatment.

analyzed from 120 patients; four samples demonstrated levels of human antichimeric antibodies greater than the lower limit of detection, and three samples displayed neutralizing antibodies.96 However, none of the four patients from whom the samples were taken experienced allergic or anaphylactic reactions. The low incidence of human antichimeric antibody reactions permits long-term administration of IMC-C225. The most common adverse event that occurs in nearly all patients treated at the target dose is the development of a dose-related acne-like rash that is described as a sterile, nonsuppurative folliculitis (Fig 5).95 The rash is generally found on the face, neck, and upper trunk. It generally appears during the first 2 weeks of treatment, with complete resolution within 1 to 3 months after discontinuation of therapy in most, but not all, patients. The majority of patients experience a mild rash (grade 1 or 2 in severity). Fewer than 2% of patients have discontinued treatment because of the rash. While numerous therapies such as topical corticosteroids, topical antibiotics, oral antibiotics, and isotretinoin have been used in an attempt to lessen the severity of the rash, none have shown clear therapeutic benefit. Given the distribution of EGFR in epithelial tissues, skin reactions appear to be a toxicity shared by many agents in the class of EGFR inhibitors. Unlike the small molecules (eg, tyrosine kinase inhibitors), these agents are not likely to produce clinically significant diarrhea because of their inability to cross into the lumen of the gastrointestinal tract.

IMC-225 IN THE TREATMENT OF HEAD & NECK CANCER

27

Fig 5. Acne-like rash related to IMC-C225 administration.

CONCLUSIONS

Given the high incidence of EGFR expression in SCCHN, the poor prognostic outcomes associated with EGFR expression, the high proportion of patients who relapse, and the promising preclinical results, EGFR blockade with the anti-EGFR mAb IMC-C225 provides an appealing treatment option for patients with head and neck cancers, particularly when it is combined with other modalities. IMC-C225 has undergone clinical testing in more than 750 patients to date. Phase I/II results have been encouraging, and results from phase II/III testing are eagerly anticipated. In addition, single-agent IMC-C225 trials are now planned in SCCHN that will help with the interpretation of the combination data. IMC-C225 offers a potentially valuable addition to the treatment of tumors that express EGFR in a patient population traditionally reporting poor outcomes. Future trials will examine the efficacy and safety of IMC-C225 combined with radiation therapy plus chemotherapy as first-line treatment in patients with SCCHN. REFERENCES 1. Greenlee RT, Hill-Harmon MB, Murray T, et al: Cancer statistics, 2001. CA Cancer J Clin 51:15-36, 2001 2. Vokes EE, Weichselbaum RR, Lippman SM, et al: Medical progress: Head and neck cancer. N Engl J Med 328:184194, 1993

3. Jacobs C: The internist in the management of head and neck cancer. Ann Intern Med 113:771-778, 1990 4. Vokes EE: Head and neck cancer, in Perry MC (ed): Chemotherapy Source Book. Philadelphia, PA, Lippincott, Williams & Wilkins, 1992, pp 918-931 5. Tupchong L, Scott CB, Blitzer PH, et al: Randomized study of preoperative versus postoperative radiation therapy in advanced head and neck carcinoma: Long-term follow-up of RTOG study 73-03. Int J Radiat Oncol Biol Phys 20:21-28, 1991 6. Harari PM, Kinsella TJ: Advances in radiation therapy for head and neck cancer. Curr Opin Oncol 7:248-254, 1995 7. Fowler JF, Lindstrom MJ: Loss of local control with prolongation in radiotherapy. Int J Radiat Oncol Biol Phys 23: 457-467, 1992 8. Huang S-M, Li J, Harari PM: Monoclonal antibody blockade of the epidermal growth factor receptor in cancer therapy, in Giaccone G, Schilsky R, Sondel P (eds): Cancer Chemotherapy and Biologic Response Modifiers. Amsterdam, Netherlands, Elsevier, 2001, pp 339-352 9. Wells A: The epidermal growth factor receptor (EGFR)–A new target in cancer therapy. Signal 1:4-11, 2001 10. Huang S-M, Harari PM: Epidermal growth factor receptor inhibition in cancer therapy: Biology, rationale and preliminary clinical results. Invest New Drugs 17:259-269, 1999 11. Baselga J: New technologies in epidermal growth factor receptor-targeted cancer therapy. Signal 1:12-21, 2001 12. Baselga J, Mendelsohn J: Receptor blockade with monoclonal antibodies as anti-cancer therapy. Pharmacol Ther 64: 127-154, 1994 13. Modjtahedi H, Styles JM, Dean CJ: The human EGF receptor as a target for cancer therapy: Six new rat mAbs against the receptor on the breast carcinoma MDA-MB 468. Br J Cancer 67:247-253, 1993 14. Prewett M, Rockwell P, Rockwell RF, et al: The biologic

28

effects of C225, a chimeric monoclonal antibody to the EGFR, on human prostate carcinoma. J Immunother 19:419-427, 1996 15. Yang XD, Jia XC, Corvalan JR, et al: Eradication of established tumors by a fully human monoclonal antibody to the epidermal growth factor receptor without concomitant chemotherapy. Cancer Res 59:1236-1243, 1999 16. Fry DW: Inhibition of the epidermal growth factor receptor family of tyrosine kinases as an approach to cancer chemotherapy: Progression from reversible to irreversible inhibitors. Pharmacol Ther 82:207-218, 1999 17. Schmidt M, Wels W: Targeted inhibition of tumour cell growth by a bispecific single-chain toxin containing an antibody domain and TGF alpha. Br J Cancer 74:853-862, 1996 18. Chandler LA, Sosnowski BA, McDonald JR, et al: Targeting tumor cells via EGF receptors: Selective toxicity of an HBEGF-toxin fusion protein. Int J Cancer 78:106-111, 1998 19. Azemar M, Schmidt M, Arlt F, et al: Recombinant antibody toxins specific for ErbB2 and EGF receptor inhibit the in vitro growth of human head and neck cancer cells and cause rapid tumor regression in vivo. Int J Cancer 86:269-275, 2000 20. Rubin Grandis J, Charaborty A, Melhem MF, et al: Inhibition of epidermal growth factor receptor gene expression and function decreases proliferation of head and neck squamous carcinoma but not normal mucosal epithelial cells. Oncogene 15:409-416, 1997 21. Moroni MC, Willingham MC, Benguinot L: EGF-R antisense RNA blocks expression of the epidermal growth factor receptor and suppresses the transforming phenotype of a human carcinoma cell line. J Biol Chem 267:2714-2722, 1992 22. He Y, Zeng Q, Drenning SD, et al: Inhibition of human squamous cell carcinoma growth in vivo by epidermal growth factor receptor antisense RNA transcribed from the U6 promoter. J Natl Cancer Inst 90:1080-1087, 1998 23. Carpenter G, Cohen S: Epidermal growth factor. J Biol Chem 265:7709-7712, 1990 24. Harari PM, Huang S-M: Modulation of molecular targets to enhance radiation. Clin Cancer Res 6:323-325, 2000 25. Schlessinger J: The epidermal growth factor receptor as a multifunctional allosteric protein. Biochemistry 27:31193123, 1988 26. Salomon DS, Brandt R, Ciardiello F, et al: Epidermal growth factor-related peptides and their receptors in human malignancies. Crit Rev Oncol Hematol 19:183-232, 1995 27. Carpenter G, Cohen S: Epidermal growth factor. Annu Rev Biochem 48:193-216, 1979 28. Yarden Y, Ullrich A: Growth factor receptor tyrosine kinases. Annu Rev Biochem 57:443-478, 1988 29. Yarden Y, Sliwkowski MX: Untangling the ErbB signalling network. Natl Rev Mol Cell Biol 2:127-136, 2001 30. Carpenter G, Cohen S: 125I-labelled human epidermal growth factor: Binding, internalization, and degradation in human fibroblasts. J Cell Biol 71:159-171, 1976 31. Rodeck U, Jost M, Kari C, et al: EGF-R dependent regulation of keratinocyte survival. J Cell Sci 110:113-121, 1997 32. Gibson S, Tu S, Oyer R, et al: Epidermal growth factor protects epithelial cells against Fas-induced apoptosis requirement for Akt activation. J Biol Chem 274:17612-17618, 1999 33. Petit AMV, Rak J, Hung M-C, et al: Neutralizing antibodies against epidermal growth factor and ErbB-2/neu receptor tyrosine kinases down-regulate vascular endothelial growth

HERBST AND HONG

factor production by tumor cells in vitro and in vivo angiogenic implications for signal transduction therapy of solid tumors. Am J Pathol 151:1523-1530, 1997 34. Perrotte P, Matsumoto T, Inoue K, et al: Anti-epidermal growth factor receptor antibody C225 inhibits angiogenesis in human transitional cell carcinoma growing orthotopically in nude mice. Clin Cancer Res 5:257-265, 1999 35. Kondapaka SB, Fridman R, Reddy KB: Epidermal growth factor and amphiregulin up-regulate matrix metalloproteinase-9 (MMP-9) in human breast cancer cells. Int J Cancer 70:722-726, 1997 36. Price JT, Wilson HM, Haites NE: Epidermal growth factor (EGF) increases the in vitro invasion, motility and adhesion interactions of the primary renal carcinoma cell line, A704. Eur J Cancer 32A:1977-1982, 1996 37. Shibata T, Kawano T, Nagayasu H, et al: Enhancing effects of epidermal growth factor on human squamous cell carcinoma motility and matrix degradation but not growth. Tumour Biol 17:168-175, 1996 38. Matsumoto T, Perrotte P, Bar-Eli M, et al: Blockade of EGF-R signaling with anti-EGF-R monoclonal antibody (Mab) C225 inhibits matrix metalloproteinases-9 (MMP-9) expression and invasion of human transitional cell carcinoma (TCC) in vitro and in vivo. Proc Am Assoc Cancer Res 39:565, 1998 (abstr) 39. Xie H, Turner T, Wang M-H, et al: In vitro invasiveness of DU-145 human prostate carcinoma cells is modulated by EGF receptor-mediated signals. Clin Exp Metastasis 13:407419, 1995 40. Carpenter G: Receptors for epidermal growth factor and other polypeptide mitogens. Annu Rev Biochem 56:881-914, 1987 41. Gullick WJ: Prevalence of aberrant expression of the epidermal growth factor receptor in human cancers. Br Med Bull 47:87-98, 1991 42. Shin DM, Ro JY, Hong WK, et al: Dysregulation of epidermal growth factor receptor expression in premalignant lesions during head and neck tumorigenesis. Cancer Res 54: 3153-3159, 1994 43. Grandis JR, Melhem MF, Barnes EL, et al: Quantitative immunohistochemical analysis of transforming growth factoralpha and epidermal growth factor receptor in patients with squamous cell carcinoma of the head and neck. Cancer 78: 1284-1292, 1996 44. Stanton P, Richards S, Reeves J, et al: Epidermal growth factor receptor expression by human squamous cell carcinomas of the head and neck, cell lines and xenografts. Br J Cancer 70:427-433, 1994 45. Kawamoto T, Takahashi K, Nishi M, et al: Quantitative assay of epidermal growth factor receptor in human squamous cell carcinomas of the oral region by an avidin-biotin method. Jpn J Cancer Res 82:403-410, 1991 46. Volm M, Rittgen W, Drings P: Prognostic value of ERBB-1, VEGF, cyclin A, FOS, JUN and MYC in patients with squamous cell lung carcinomas. Br J Cancer 77:663-669, 1998 47. Bartlett JMS, Langdon SP, Simpson BJB, et al: The prognostic value of epidermal growth factor receptor mRNA expression in primary ovarian cancer. Br J Cancer 73:301-306, 1996 48. Pavelic K, Banjac Z, Pavelic J, et al: Evidence for a role

IMC-225 IN THE TREATMENT OF HEAD & NECK CANCER

of EGF receptor in the progression of human lung carcinoma. Anticancer Res 13:1133-1137, 1993 49. Neal DE, Sharples L, Smith K, et al: The epidermal growth factor receptor and the prognosis of bladder cancer. Cancer 65:1619-1625, 1990 50. Nikura H, Sasano H, Sato S, et al: Expression of epidermal growth factor-related proteins and epidermal growth factor receptor in common epithelial ovarian tumors. Int J Gynecol Pathol 16:60-68, 1997 51. Grandis JR, Melhem MF, Gooding WE, et al: Levels of TGF-alpha and EGFR protein in head and neck squamous cell carcinoma and patient survival. J Natl Cancer Inst 90:824-832, 1998 52. Maurizi M, Almadori G, Ferrandina G, et al: Prognostic significance of epidermal growth factor receptor in laryngeal squamous cell carcinoma. Br J Cancer 74:1253-1257, 1996 53. Todd R, Donoff BR, Gertz R, et al: TGF-alpha and EGF-receptor mRNAs in human oral cancers. Carcinogenesis 10:1553-1556, 1989 54. Santini J, Formento J-L, Francoual M, et al: Characterization, quantification, and potential clinical value of the epidermal growth factor receptor in head and neck squamous cell carcinomas. Head Neck 13:132-139, 1991 55. Ke LD, Adler-Storthz K, Clayman GL, et al: Differential expression of epidermal growth factor receptor in human head and neck cancers. Head Neck 20:320-327, 1998 56. Mendelsohn J: Epidermal growth factor receptor inhibition by a monoclonal antibody as anticancer therapy. Clin Cancer Res 3:2703-2707, 1997 57. Shitara K, Kuwana Y, Nakamura K, et al: A mouse/ human chimeric anti-(ganglioside GD3) antibody with enhanced antitumor activities. Cancer Immunol Immunother 36:373-380, 1993 58. LoBuglio AF, Wheeler RH, Trang J, et al: Mouse/human chimeric monoclonal antibody in man: Kinetics and immune response. Proc Natl Acad Sci U S A 86:4220-4224, 1989 59. Goldstein NI, Prewett M, Zuklys K, et al: Biological efficacy of a chimeric antibody to the epidermal growth factor receptor in a human tumor xenograft model. Clin Cancer Res 1:1311-1318, 1995 60. Gill GN, Kawamoto T, Cochet C, et al: Monoclonal anti-epidermal growth factor receptor antibodies which are inhibitors of epidermal growth factor binding and antagonists of epidermal growth factor-stimulated tyrosine protein kinase activity. J Biol Chem 259:7755-7760, 1984 61. Kawamoto T, Mendelsohn J, Le A, et al: Relation of epidermal growth factor receptor concentration to growth of human epidermoid carcinoma A431 cells. J Biol Chem 259: 7761-7766, 1984 62. Kawamoto T, Sato JD, Le A, et al: Growth stimulation of A431 cells by epidermal growth factor: Identification of high-affinity receptors for epidermal growth factor by an antireceptor monoclonal antibody. Proc Natl Acad Sci U S A 80:1337-1341, 1983 63. Sato JD, Kawamoto T, Le AD, et al: Biological effects in vitro of monoclonal antibodies to human epidermal growth factor receptors. Mol Biol Med 1:511-529, 1983 64. Sunada H, Magun BE, Mendelsohn J, et al: Monoclonal antibody against epidermal growth factor receptor is internalized without stimulating receptor phosphorylation. Proc Natl Acad Sci U S A 83:3825-3829, 1986

29

65. Baselga J, Pfister D, Cooper MR, et al: Phase I studies of anti-epidermal growth factor receptor chimeric antibody C225 alone and in combination with cisplatin. J Clin Oncol 18:904914, 2000 66. Shin DM, Donato NJ, Perez-Soler R, et al: Epidermal growth factor receptor-targeted therapy with C225 and cisplatin in patients with head and neck cancer. Clin Cancer Res 7:1204-1213, 2001 67. Huang S-M, Bock JM, Harari PM: Epidermal growth factor receptor blockade with C225 modulates proliferation, apoptosis, and radiosensitivity in squamous cell carcinomas of the head and neck. Cancer Res 59:1935-1940, 1999 68. Wu X, Rubin M, Fan Z, et al: Involvement of p27KIP1 in G1 arrest mediated by an anti epidermal growth factor receptor monoclonal antibody. Oncogene 12:1397-1403, 1996 69. Peng D, Fan Z, Lu Y, et al: Anti-epidermal growth factor receptor monoclonal antibody C225 up-regulates p27KIP1 and induces G1 arrest in prostatic cancer cell line DU145. Cancer Res 56:3666-3669, 1996 70. Wu X, Fan Z, Masui H, et al: Apoptosis induced by an anti-epidermal growth factor receptor monoclonal antibody in a human colorectal carcinoma cell line and its delay by insulin. J Clin Invest 95:1897-1905, 1995 71. Mandal M, Adam L, Mendelsohn J, et al: Nuclear targeting of Bax during apoptosis in human colorectal cancer cells. Oncogene 17:999-1007, 1998 72. Liu B, Fang M, Schmidt M, et al: Induction of apoptosis and activation of the caspase cascade by anti-EGF receptor monoclonal antibodies in DiFi human colon cancer cells do not involve the c-jun N-terminal kinase activity. Br J Cancer 82:1991-1999, 2000 73. Huang S-M, Harari PM: Modulation of radiation response after epidermal growth factor receptor blockade in squamous cell carcinomas: Inhibition of damage repair, cell cycle kinetics, and tumor angiogenesis. Clin Cancer Res 6:21662174, 2000 74. Bruns CJ, Harbison MT, Davis DW, et al: Epidermal growth factor receptor blockade with C225 plus gemcitabine results in regression of human pancreatic carcinoma growing orthotopically in nude mice by antiangiogenic mechanisms. Clin Cancer Res 6:1936-1948, 2000 75. Harari PM, Huang S-M: Head and neck cancer as a clinical model for molecular targeting of therapy: Combining EGFR blockade with radiation. Int J Radiat Oncol Biol Phys 49:427-433, 2001 76. Zhu A, Shaffer J, Leslie S, et al: Epidermal growth factor receptor: An independent predictor of survival in astrocytic tumors given definitive irradiation. Int J Radiat Oncol Biol Phys 34:809-815, 1996 77. Sheridan MT, O’Dwyer T, Seymour CB, et al: Potential indicators of radiosensitivity in squamous cell carcinoma of the head and neck. Radiat Oncol Invest 5:180-186, 1997 78. Iliakis G: Cell cycle regulation in irradiated and nonirradiated cells. Semin Oncol 24:602-615, 1997 79. Prewett M, Rockwell P, Rose C, et al: Anti-tumor and cell cycle responses in KB cells treated with a chimeric antiEGFR monoclonal antibody in combination with cisplatin. Int J Oncol 9:217-224, 1996 80. Fan Z, Baselga J, Masui H, et al: Antitumor effect of anti-epidermal growth factor receptor monoclonal antibodies

30

plus cis-diamminedichloroplatinum on well established A431 cell xenografts. Cancer Res 53:4637-4642, 1993 81. Wen X, Li C, Wu Q-P, et al: Potentiation of antitumor activity of PG-TXL with anti-EGFR monoclonal antibody C225 in MDA-MB-468 human breast cancer xenograft. Proc Am Assoc Cancer Res 41:323, 2000 (abstr 2052) 82. Prewett M, Rockwell P, Rose C, et al: Altered cell cycle distribution and cyclin-CDK protein expression in A431 epidermoid carcinoma cells treated with doxorubicin and a chimeric monoclonal antibody to the epidermal growth factor receptor. Mol Cell Diff 4:167-186, 1996 83. Baselga J, Norton L, Masui H, et al: Antitumor effects of doxorubicin in combination with anti-epidermal growth factor receptor monoclonal antibodies. J Natl Cancer Inst 85:13271333, 1993 84. Goldstein NI, Prewett M, Rockwell P, et al: Treatment of human tumor xenografts with a chimeric monoclonal antibody to the epidermal growth factor receptor in combination with Doxil, a novel liposomal form of doxorubicin. Monoclonal Antibodies & Cancer Therapy. New York, October 16-18, 1995 (abstr) 85. Ciardiello F, Bianco R, Damiano V, et al: Antitumor activity of sequential treatment with topotecan and anti-epidermal growth factor receptor monoclonal antibody C225. Clin Cancer Res 5:909-916, 1999 86. Overholser JP, Prewett MC, Hooper AT, et al: Epidermal growth factor receptor blockade by antibody IMC-C225 inhibits growth of a human pancreatic carcinoma xenograft in nude mice. Cancer 89:74-82, 2000 87. Raben D, Buchsbaum DJ, Gillespie Y, et al: Treatment of human intracranial gliomas with chimeric monoclonal antibody against the epidermal growth factor receptor increases survival of nude mice when treated concurrently with irradiation. Proc Am Assoc Cancer Res 40:184, 1999 (abstr 1224) 88. Saleh MN, Raisch KP, Stackhouse MA, et al: Combined modality therapy of A431 human epidermoid cancer using anti-EGFR antibody C225 and radiation. Cancer Biother Radiopharm 14:451-463, 1999 89. Trummel HQ, Raisch KP, Ahmed A, et al: The biolog-

HERBST AND HONG

ical effects of anti-epidermal growth factor receptor and ionizing radiation in human head and neck tumor cell lines. Proc Am Assoc Cancer Res 40:144, 1999 (abstr 958) 90. Milas L, Mason K, Hunter N, et al: In vivo enhancement of tumor radioresponse by C225 antiepidermal growth factor receptor antibody. Clin Cancer Res 6:701-708, 2000 91. Perez-Soler R, Shin DM, Donato N, et al: Tumor studies in patients with head & neck cancer treated with humanized anti-epidermal growth factor (EGFR) monoclonal antibody C225 in combination with cisplatin. Proc Am Soc Clin Oncol 17:393a, 1998 (abstr 1514) 92. Shin DM, Donato NJ, Perez-Soler R, et al: Epidermal growth factor receptor-targeted therapy with C225 and cisplatin in patients with head and neck cancer. Clin Cancer Res 7:1204-1213, 2001 93. Bonner JA, Ezekiel MP, Robert F, et al: Continued response following treatment with IMC-C225, an EGFr MoAb, combined with RT in advanced head and neck malignancies. Proc Am Soc Clin Oncol 19:4a, 2000 (abstr 5F) 94. Herbst RS, Arquette MA, Nabell L, et al: Efficacy and safety of the anti-epidermal growth factor antibody IMC-C225, in combination with cisplatin in patients with recurrent squamous cell carcinoma of the head and neck refractory to cisplatin containing chemotherapy. 2001 Proceedings of the American Association for Cancer Research National Cancer Institute-European Organization for Research and Treatment of Cancer International Conference, Miami Beach, FL, Oct 29 –Nov 2, 2001, p 113 (abstr 554) 95. Cohen RB, Falcey JW, Paulter VJ, et al: Safety profile of the monoclonal antibody (MoAb) IMC-C225, an anti-epidermal growth factor receptor (EGFr) used in the treatment of EGFr- positive tumors. Proc Am Soc Clin Oncol 19:474a, 2000 (abstr 1862) 96. Khazaeli MB, LoBuglio AF, Falcey JW, et al: Low immunogenicity of a chimeric monoclonal antibody (MoAb), IMC-C225, used to treat epidermal growth factor receptorpositive tumors. Proc Am Soc Clin Oncol 19:207a, 2000 (abstr 808)