Wendie Hopkins

A phase I clinical trial with monoclonal antibody ch806 targeting transitional state and mutant epidermal growth factor receptors

An array of cell-surface antigens expressed by human cancers have been identified as targets for antibody-based therapies. The great majority of these antibodies do not have specificity for cancer but recognize antigens expressed on a range of normal cell types (differentiation antigens). Over the past two decades, our group has analyzed thousands of mouse monoclonal antibodies for cancer specificity and identified a battery of antibodies with limited representation on normal human cells. The most tumor-specific of these antibodies is 806, an antibody that detects a unique epitope on the epidermal growth factor receptor (EGFR) that is exposed only on overexpressed, mutant, or ligand-activated forms of the receptor in cancer. In vitro immunohistochemical specificity analysis shows little or no detectable 806 reactivity with normal tissues, even those with high levels of wild-type (wt)EGFR expression. Preclinical studies have demonstrated that 806 specifically targets a subset of EGFR expressed on tumor cells, and has significant anti-tumor effects on human tumor xenografts, primarily through abrogation of signaling pathways. The present clinical study was designed to examine the in vivo specificity of a chimeric form of mAb 806 (ch806) in a tumor targeting/biodistribution/pharmacokinetic analysis in patients with diverse tumor types. ch806 showed excellent targeting of tumor sites in all patients, no evidence of normal tissue uptake, and no significant toxicity. These in vitro and in vivo characteristics of ch806 distinguish it from all other antibodies targeting EGFR.

Regulatory T-Cell–Mediated Attenuation of T-Cell Responses to the NY-ESO-1 ISCOMATRIX Vaccine in Patients with Advanced Malignant Melanoma

Purpose: NY-ESO-1 is a highly immunogenic antigen expressed in a variety of malignancies, making it an excellent target for cancer vaccination. We recently developed a vaccine consisting of full-length recombinant NY-ESO-1 protein formulated with ISCOMATRIX adjuvant, which generated strong humoral and T-cell–mediated immune responses and seemed to reduce the risk of disease relapse in patients with fully resected melanoma. This study examines the clinical and immunologic efficacy of the same vaccine in patients with advanced metastatic melanoma. Experimental Design: Delayed-type hypersensitivity responses, circulating NY-ESO-1–specific CD4+ and CD8+ T cells, and proportions of regulatory T cells (Treg) were assessed in patients. Results: In contrast to patients with minimal residual disease, advanced melanoma patients showed no clinical responses to vaccination. Although strong antibody responses were mounted, the generation of delayed-type hypersensitivity responses was significantly impaired. The proportion of patients with circulating NY-ESO-1–specific CD4+ T cells was also reduced, and although many patients had CD8+ T cells specific to a broad range of NY-ESO-1 epitopes, the majority of these responses were preexisting. Tregs were enumerated in the blood by flow cytometric detection of cells with a CD4+CD25+FoxP3+ and CD4+CD25+CD127− phenotype. Patients with advanced melanoma had a significantly higher proportion of circulating Treg compared with those with minimal residual disease. Conclusions: Our results point to a tumor-induced systemic immune suppression, showing a clear association between the stage of melanoma progression, the number of Treg in the blood, and the clinical and immunologic efficacy of the NY-ESO-1 ISCOMATRIX cancer vaccine.

A Phase I Trial of Humanized Monoclonal Antibody A33 in Patients with Colorectal Carcinoma: Biodistribution, Pharmacokinetics, and Quantitative Tumor Uptake

Purpose: To determine the in vivo characteristics of huA33, a CDR-grafted humanized antibody against the A33 antigen, we have conducted an open-label, dose escalation, biopsy-based phase I trial of huA33 in patients with colorectal carcinoma. Experimental Design: Patients with colorectal carcinoma were infused with [131I]huA33 (400 MBq: 10 mCi) and [125I]huA33 (40 MBq: 1 mCi) 1 week before surgery. There were four huA33 dose levels (0.25, 1.0, 5.0, and 10 mg/m2). Adverse events, pharmacokinetics, biodistribution, tumor biopsies, and immune responses to huA33 were evaluated. Results: There were 12 patients entered into the trial (6 males and 6 females; age range, 39-66 years). No dose-limiting toxicity was observed. The biodistribution of huA33 showed excellent uptake of [131I]huA33 in metastatic colorectal carcinoma. Pharmacokinetic analysis showed no significant difference in terminal half-life (T1/2β) between dose levels (mean ± SD, 86.92 ± 22.12 hours). Modeling of colon uptake of huA33 showed a T1/2 of elimination of 32.4 ± 8.1 hours. Quantitative tumor uptake ranged from 2.1 × 10−3 to 11.1 × 10−3 %ID/g, and tumor/normal tissue and tumor/serum ratios reached as high as 16.3:1 and 4.5:1, respectively. Biosensor analysis detected low-level human anti-human antibody responses in four patients following huA33 infusion. Conclusions: huA33 shows selective and rapid localization to colorectal carcinoma in vivo and penetrates to the center of large necrotic tumors, and colon elimination half-life of huA33 is equivalent to basal colonocyte turnover. The excellent targeting characteristics of this humanized antibody indicate potential for the targeted therapy of metastatic colorectal cancer in future trials.

Specific Targeting, Biodistribution, and Lack of Immunogenicity of Chimeric Anti-GD3 Monoclonal Antibody KM871 in Patients With Metastatic Melanoma: Results of a Phase I Trial

PURPOSE KM871 is a chimeric monoclonal antibody against the ganglioside antigen GD3, which is highly expressed on melanoma cells. We conducted an open-label, dose escalation phase I trial of KM871 in patients with metastatic melanoma. PATIENTS AND METHODS Seventeen patients were entered onto one of five dose levels (1, 5, 10, 20, and 40 mg/m2). Patients received three infusions of KM871 at 2-week intervals, with the first infusion of KM871 trace-labeled with indium-111 (111In) to enable assessment of biodistribution in vivo. Biopsies of metastatic melanoma sites were performed on days 7 to 10. RESULTS Fifteen of 17 patients completed a cycle of three infusions of KM871. No dose-limiting toxicity was observed during the trial; the maximum-tolerated dose was therefore not reached. Three patients (at the 1-, 5-, and 40-mg/m2 dose levels) developed pain and/or erythema at tumor sites consistent with an inflammatory response. No normal tissue uptake of 111In-KM871 was observed, and tumor uptake of 111In-KM871 was observed in all lesions greater than 1.5 cm (tumor biopsy 111KM871 uptake results: range, 0.001% to 0.026% injected dose/g). The ratio of maximum tumor to normal tissue was 15:1. Pharmacokinetic analysis revealed a 111In-KM871 terminal half-life of 7.68 +/- 2.94 days. One patient had a clinical partial response that lasted 11 months. There was no serologic evidence of human antichimeric antibody in any patient, including one patient who received 16 infusions over a 12-month period. CONCLUSION This study is the first to demonstrate the biodistribution and specific targeting of an anti-GD3 antibody to metastatic melanoma in patients. The long half-life and lack of immunogenicity of KM871 makes this antibody an attractive potential therapy for patients with metastatic melanoma.

Blood dendritic cells generated with Flt3 ligand and CD40 ligand prime CD8+ T cells efficiently in cancer patients.

Flt3 ligand mobilizes dendritic cells (DCs) into blood, allowing generation in vivo of large numbers of DCs for immunotherapy. These immature DCs can be rapidly activated by soluble CD40 ligand (CD40L). We developed a novel overnight method using these cytokines to produce DCs for cancer immunotherapy. Flt3 ligand-mobilized DCs (FLDCs) were isolated, activated with CD40L, loaded with antigenic peptides from influenza matrix protein, hepatitis B core antigen, NY-ESO-1, MAGE-A4, and MAGE-A10, and injected into patients with resected melanoma. Three injections were given at 4-week intervals. Study end points included antigen-specific immune responses (skin reactions to peptides alone or peptide-pulsed FLDCs; circulating T-cell responses), safety, and toxicity. No patient had a measurable tumor. Six patients were entered. FLDCs were obtained, enriched, and cultured under Good Manufacturing Practice grade conditions. Overnight culture with soluble CD40L caused marked up-regulation of activation markers (CD83 and HLA-DR). These FLDCs were functional and able to stimulate antigen-specific T cells in vitro. No significant adverse events were attributable to FLDCs. Peptide-pulsed FLDCs caused strong local skin reactions up to 60 mm diameter with intense perivascular infiltration of T cells, exceeding those seen in our previous peptide-based protocols. Antigen-specific blood T-cell responses were induced, including responses to an antigen for which the patients were naive (hepatitis B core antigen) and MAGE-A10. MAGE-A10–specific T cells with a skewed T-cell receptor repertoire were detected in 1 patient in blood ex vivo and from tumor biopsies. Vaccination with FLDCs pulsed with peptides is safe and primes immune responses to cancer antigens.

A Phase I Biodistribution and Pharmacokinetic Trial of Humanized Monoclonal Antibody Hu3s193 in Patients with Advanced Epithelial Cancers that Express the Lewis-Y Antigen

Purpose: We report a first-in-man trial of a humanized antibody (hu3S193) against the Ley antigen. Experimental Design: Patients with advanced Ley-positive cancers received four infusions of hu3S193 at weekly intervals, with four dose levels (5, 10, 20, and 40 mg/m2). The first infusion of hu3S193 was trace labeled with Indium-111, and biodistribution, pharmacokinetics, tumor uptake, and immune response were evaluated in all patients. Results: A total of 15 patients (7 male/8 female; age range, 42-76 years; 6 breast, 8 colorectal cancer, and 1 non–small-cell lung cancer) were entered into the study. Transient grade 1 to 2 nausea and vomiting was observed following infusion of hu3S193 at the 40mg/m2 dose level only. There was one episode of dose-limiting toxicity with self-limiting Common Toxicity Criteria grade 3 elevated alkaline phosphatase observed in one patient with extensive liver metastases. The biodistribution of 111In-hu3S193 showed no evidence of any consistent normal tissue uptake, and 111In-hu3S193 uptake was observed in cutaneous, lymph node, and hepatic metastases. Hu3S193 displayed a long serum half-life (T1/2β = 189.63 ± 62.17 h). Clinical responses consisted of 4 patients with stable disease and 11 patients with progressive disease, although one patient experienced a 89% decrease in a lymph node mass, and one patient experienced inflammatory symptoms in cutaneous metastases, suggestive of a biological effect of hu3S193. No immune responses (human anti-human antibody) to hu3S193 were observed. Conclusion: Hu3S193 is well tolerated and selectively targets tumors, and the long half-life and biological function in vivo of this antibody makes it an attractive potential therapy for patients with Ley-expressing cancers.

Phase I Trial of 131I-huA33 in Patients with Advanced Colorectal Carcinoma

Purpose: Humanized monoclonal antibody A33 (huA33) targets the A33 antigen which is expressed on 95% of colorectal cancers. A previous study has shown excellent tumor-targeting of iodine-131 labeled huA33 (131I-huA33). Therefore, we did a phase I dose escalation trial of 131I-huA33 radioimmunotherapy. Experimental Designs: Fifteen patients with pretreated metastatic colorectal carcinoma each received two i.v. doses of 131I-huA33. The first was an outpatient trace-labeled “scout” dose for biodistribution assessment, followed by a second “therapy” dose. Three patients were treated at 20, 30, and 40 mCi/m2 dose levels, and six patients at 50 mCi/m2 to define the maximum tolerated dose. Results: Hematologic toxicity was 131I dose-dependent, with one episode of grade 4 neutropenia and two episodes of grade 3 thrombocytopenia observed at 50 mCi/m2. The maximum tolerated dose was determined to be 40 mCi/m2. There were no acute infusion-related adverse events, and gastrointestinal toxicity was not observed despite uptake of 131I-huA33 in bowel. Seven patients developed pruritus or rash, which was not related to 131I dose. There was excellent tumor-targeting of 131I-huA33 shown in all patients. The serum T1/2β of 131I-huA33 was (mean ± SD) 135.2 ± 46.9 hours. The mean absorbed tumor dose was 6.49 ± 2.47 Gy/GBq. Four patients developed human anti-human antibodies. At restaging, 4 patients had stable disease, whereas 11 patients had progressive disease. Conclusion: Radioimmunotherapy using 131I-huA33 shows promise in targeting colorectal tumors, and is deliverable at a maximum tolerated dose of 40 mCi/m2. Further studies of 131I-huA33 in combination with chemotherapy are planned.

Phase I biodistribution and pharmacokinetic study of Lewis Y-targeting immunoconjugate CMD-193 in patients with advanced epithelial cancers.

Purpose: This phase I study explored the biodistribution and pharmacokinetics of the immunoconjugate CMD-193 [a humanized anti–Lewis Y (Ley) antibody conjugated with calicheamicin in patients with advanced cancers expressing the Ley antigen. Experimental Design: The primary objectives were to determine biodistribution and pharmacokinetics of CMD-193. Secondary objectives included response rates and change in tumor metabolism. Patients with progressive, measurable, and Ley positive malignancies were eligible for enrollment in one of two dose cohorts, 1.0 and 2.6 mg/m2. The first cycle was trace labeled with 111In for biodistribution assessment using γ camera imaging. Subsequent cycles were administered every 3 weeks up to a maximum of six cycles, depending on toxicity and response. Pharmacokinetic analysis was based on radioassay and ELISA. Results: Nine patients were enrolled in the study. Biodistribution images showed initial blood pool activity, followed by markedly increased hepatic uptake by day 2, and fast blood clearance in all patients. There was low uptake in tumor in all patients. The overall T½β of 111In-CMD-193 was 102.88 ± 35.67 hours, with no statistically significant difference between the two dose levels. One patient had a partial metabolic response on 18F-fluorodeoxyglucose-positron emission tomography (18F-FDG PET) after four cycles, but no radiological responses were observed. Myelosuppression and effects on liver function were the most significant adverse effects. Conclusions: CMD-193 shows rapid blood clearance and increased hepatic uptake compared with prior studies of the parental antibody hu3S193. These results highlight the importance of biodistribution and pharmacodynamic assessment in early phase studies of new biologics to assist in clinical development. (Clin Cancer Res 2009;15(21):6709–15)

Phase I Imaging and Pharmacodynamic Trial of CS-1008 in Patients With Metastatic Colorectal Cancer

PURPOSE CS-1008 (tigatuzumab) is a humanized, monoclonal immunoglobulin G1 (IgG1) agonistic antibody to human death receptor 5. The purpose of this study was to investigate the impact of CS-1008 dose on the biodistribution, quantitative tumor uptake, and antitumor response in patients with metastatic colorectal cancer (mCRC). PATIENTS AND METHODS Patients with mCRC who had received at least one course of chemotherapy were assigned to one of five dosage cohorts and infused with a weekly dose of CS-1008. Day 1 and day 36 doses were trace-labeled with indium-111 ((111)In), followed by whole-body planar and regional single-photon emission computed tomography (SPECT) imaging at several time points over the course of 10 days. RESULTS Nineteen patients were enrolled. (111)In-CS-1008 uptake in tumor was observed in only 12 patients (63%). (111)In-CS-1008 uptake and pharmacokinetics were not affected by dose or repeated drug administration. (111)In-CS-1008 biodistribution showed gradual blood-pool clearance and no abnormal uptake in normal tissue. No anti-CS-1008 antibody development was detected. One patient achieved partial response (3.7 months duration), eight patients had stable disease, and 10 patients had progressive disease. Clinical benefit rate (stable disease + partial response) in patients with (111)In-CS-1008 uptake in tumor was 58% versus 28% in patients with no uptake. An analysis of individual lesions showed that lesions with antibody uptake were one third as likely to progress as those without antibody uptake (P = .07). Death-receptor-5 expression in archived tumor samples did not correlate with (111)In-CS-1008 uptake (P = .5) or tumor response (P = .6). CONCLUSION Death-receptor-5 imaging with (111)In-CS-1008 reveals interpatient and intrapatient heterogeneity of uptake in tumor, is not dose dependent, and is predictive of clinical benefit in the treatment of patients who have mCRC.

Abstract 1174: A phase I imaging and pharmacodynamic trial of CS-1008 in patients (pts) with metastatic colorectal cancer (mCRC).

Background: Death receptor 5 (DR5) is a member of the TNFR superfamily that initiates the extrinsic apoptotic pathway by activating caspases. CS-1008 is a humanised, monoclonal IgG1 agonistic antibody to human DR5 created by CDR grafting of the murine antibody TRA-8. The aim of this study was to investigate the impact of CS-1008 dose on biodistribution, quantitative tumor uptake and anti-tumor response in patients with mCRC. Methods: Pts with mCRC who had received at least 1 course of chemotherapy (CT) were treated with weekly IV CS-1008 infusions in 5 non-sequential cohorts (Co). Different loading doses were used on days 1 and 8 (Co 1: 0.2 and 6 mg/kg; Co 2: 1 and 6 mg/kg; Co 3: 2 and 6 mg/kg; Co 4: 4 and 4mg/kg; Co 5: 6 and 2 mg/kg), followed by a weekly CS-1008 dose of 2 mg/kg. Cycle 1 encompassed 7 wks of therapy (D1 and D36 doses trace-labeled with 111In); additional weekly CS-1008 was scheduled as 4-wk cycles. Primary endpoints were to determine (1) the influence of CS-1008 dose on initial biodistribution, pharmacokinetic (PK) and tumor uptake of 111In-CS-1008 following single infusion; (2) changes in biodistribution, PK and tumor uptake following sequential doses. Secondary endpoints were to determine (1) anti-tumor response; (2) changes in tumor metabolism; (3) serum apoptosis biomarkers and serum tumor response markers. Results: Nineteen pts with a median age of 64 years and 2-6 prior CT lines were enrolled as follows: Co 1, 2 pts; Co 2, 4 pts; Co 3, 5 pts; Co 4, 3 pts; and Co 5, 5 pts. Twelve pts showed tumor uptake of 111In‐CS‐1008, 3 at each of the 1, 2, 4 and 6 mg/kg D1 dose levels. 111In‐CS‐1008 uptake in tumor was variable: some pts showed no uptake, in others uptake was observed in all measurable lesions. Liver metastases showed poor uptake of CS-1008. No significant differences were observed in tumor uptake between D1 and D36, and no effect of dose on tumor uptake was seen. DR5 expression in archived samples did not correlate with 111In‐CS‐1008 uptake, nor with clinical outcome. 111In‐CS‐1008 biodistribution showed gradual blood pool clearance and no discernible abnormal uptake in normal tissue. CS-1008 PK was not affected by dose or repeated drug administration. At restaging, there were 8 SD, 1 PR and 10 PD. The duration of PR was 3.7 months (mos). The mean duration of SD was 4 mos (range, 2.6-6.7 mos). Among the group of pts who showed CS-1008 uptake in tumor, 58% had clinical benefit (SD or PR), compared with 28% of pts in the group with no tumor uptake. The lesions that showed CS-1008 uptake were less likely to progress even in pts with overall PD at restaging. Conclusions: 111In-CS-1008 uptake in tumor predicts SD or PR. Tumor DR5 expression, assessed by 111In-CS-1008 imaging, reveals real-time heterogeneous DR5 expression, both on a per pt and on a lesion by lesion basis, and appears to be a promising predictive imaging biomarker of clinical benefit in pts with mCRC receiving CS-1008. Citation Format: Marika Ciprotti, Niall C. Tebbutt, Fook T. Lee, Sze T. Lee, Dave C. McKee, Graeme J. O9Keefe, Sylvia J. Gong, Geoffrey Chong, Hui K. Gan, Wendie Hopkins, Bridget Chappell, Nancy Y. Guo, Fiona E. Smyth, Archie N. Tse, Mendel Jansen, Manabu Matsumura, Rira Watanabe, Robert A. Beckman, Jon Greenberg, Andrew M. Scott. A phase I imaging and pharmacodynamic trial of CS-1008 in patients (pts) with metastatic colorectal cancer (mCRC). [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1174. doi:10.1158/1538-7445.AM2013-1174