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.

Low-dose cyclophosphamide enhances antigen-specific CD4(+) T cell responses to NY-ESO-1/ISCOMATRIX™ vaccine in patients with advanced melanoma.

Clinical outcomes from cancer vaccine trials in patients with advanced melanoma have so far been disappointing. This appears at least partially due to a state of immunosuppression in these patients induced by an expansion of regulatory cell populations including regulatory T cells (Tregs). We have previously demonstrated potent immunogenicity of the NY-ESO-1/ISCOMATRIX™ vaccine in patients with resected melanoma (study LUD99-08); however, the same vaccine induced only a few vaccine antigen-specific immune responses in patients with advanced disease (study LUD2002-013). Pre-clinical models suggest that the alkylating agent cyclophosphamide can enhance immune responses by depleting Tregs. Therefore, we have enrolled a second cohort of patients with advanced melanoma in the clinical trial LUD2002-013 to investigate whether pre-treatment with cyclophosphamide could improve the immunogenicity of the NY-ESO-1/ISCOMATRIX™ vaccine. The combination treatment led to a significant increase in vaccine-induced NY-ESO-1-specific CD4(+) T cell responses compared with the first trial cohort treated with vaccine alone. We could not detect a significant decline in regulatory T cells in peripheral blood of patients 14 days after cyclophosphamide administration, although a decline at an earlier time point cannot be excluded. Our observations support the inclusion of cyclophosphamide in combination trials with vaccines and other immune-modulatory agents.

Targeted chemoradiation in metastatic colorectal cancer: a phase I trial of 131I-huA33 with concurrent capecitabine.

UNLABELLED: huA33 is a humanized antibody that targets the A33 antigen, which is highly expressed in intestinal epithelium and more than 95% of human colon cancers but not other normal tissues. Previous studies have shown huA33 can target and be retained in a metastatic tumor for 6 wk but eliminated from normal colonocytes within days. This phase I study used radiolabeled huA33 in combination with capecitabine to target chemoradiation to metastatic colorectal cancer. The primary objective was safety and tolerability of the combination of capecitabine and (131)I-huA33. Pharmacokinetics, biodistribution, immunogenicity, and tumor response were also assessed. METHODS: Eligibility included measurable metastatic colorectal cancer, adequate hematologic and biochemical function, and informed consent. An outpatient scout (131)I-huA33 dose was followed by a single-therapy infusion 1 wk later, when capecitabine was commenced. Dose escalation occurred over 5 dose levels. Patients were evaluated weekly, with tumor response assessment at the end of the 12-wk trial. Tumor targeting was assessed using a γ camera and SPECT imaging. RESULTS: Nineteen eligible patients were enrolled. The most frequently observed toxicity included myelosuppression, gastrointestinal symptoms, and asymptomatic hyperbilirubinemia. Biodistribution analysis demonstrated excellent tumor targeting of the known tumor sites, expected transient bowel uptake, but no other normal tissue uptake. (131)I-huA33 demonstrated a mean terminal half-life and serum clearance suited to radioimmunotherapy (T1/2ß, 100.24 ± 20.92 h, and clearance, 36.72 ± 8.01 mL/h). The mean total tumor dose was 13.8 ± 7.6 Gy (range, 5.1-26.9 Gy). One patient had a partial response, and 10 patients had stable disease. CONCLUSION: (131)I-huA33 achieves specific targeting of radiotherapy to colorectal cancer metastases and can be safely combined with chemotherapy, providing an opportunity to deliver chemoradiation specifically to metastatic disease in colorectal cancer patients.

Immunoediting and persistence of antigen-specific immunity in patients who have previously been vaccinated with NY-ESO-1 protein formulated in ISCOMATRIX™.

BACKGROUND: NY-ESO-1 protein formulated in ISCOMATRIX™ results in CD4+, CD8+ T cell and antibody-mediated immunity. We evaluated persistence of immunity, relapse-free survival and tumour antigen expression upon relapse in patients vaccinated in an earlier trial. METHODS: Immunity was measured in 28 patients with resected NY-ESO-1-expressing tumours (melanoma 25, breast 3) 252-1,155 days (median = 681) after vaccination. In the earlier vaccination, trial patients received NY-ESO-1 with ISCOMATRIX™ adjuvant at three protein doses 10 µg, 30 µg or 100 µg (n = 14); 100 µg NY-ESO-1 protein (n = 8) or placebo (n = 6), together with 1 µg of intradermal (ID) NY-ESO-1 protein twice for DTH skin testing. Immune responses assessed in the current study included antibody titres, circulating NY-ESO-1-specific T cells and DTH reactivity 2 days after DTH skin testing with NY-ESO-1 protein (1 µg) or peptides (10 µg). Relapse-free survival was determined for 42 melanoma patients. On relapse NY-ESO-1 and HLA, class I was assessed by immunohistochemistry in 17. RESULTS: Persisting anti-NY-ESO-1 immunity was detected in 10/14 recipients who had previously received vaccine with ISCOMATRIX™ adjuvant. In contrast, immunity only persisted in 3/14 who received 100 µg un-adjuvanted NY-ESO-1 protein (3/8) or 2 µg DTH protein (0/6) P = 0.02. Hence, persisting NY-ESO-1 immunity was associated with prior adjuvant. Tumour NY-ESO-1 or HLA class I was downregulated in participants who relapsed suggesting immunoediting had occurred. CONCLUSION: Immunoediting suggests that a signal of anti-tumour activity was observed in high-risk resected melanoma patients vaccinated with NY-ESO-1/ISCOMATRIX™. This was associated with measurable persisting immunity in the majority of vaccinated subjects tested. A prospective randomised trial has been undertaken to confirm these results.

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 (Le(y)) antibody conjugated with calicheamicin in patients with advanced cancers expressing the Le(y) 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 Le(y) positive malignancies were eligible for enrollment in one of two dose cohorts, 1.0 and 2.6 mg/m(2). The first cycle was trace labeled with (111)In for biodistribution assessment using gamma 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 T(1/2)beta of (111)In-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 (18)F-fluorodeoxyglucose-positron emission tomography ((18)F-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.

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 multiple dose, dose escalation study of cG250 monoclonal antibody in patients with advanced renal cell carcinoma.

The chimeric monoclonal antibody cG250 recognises the G250/CAIX/MN antigen found on 95% of clear cell renal cell carcinomas (RCCs). We performed a phase I clinical trial to evaluate the safety, blood pharmacokinetics (PK), and biodistribution of repeated doses of cG250. The primary endpoint was toxicity. Secondary endpoints were cG250 biodistribution and PK; measurement of human anti-chimeric-antibodies (HACA); and tumour response rates. Eligible patients had unresectable or metastatic clear cell RCC. Doses of 5, 10, 25, or 50 mg/m(2) were given weekly by intravenous infusion for six weeks. Three patients were treated at each dose level. Trace (131)I-labelled cG250 was administered on weeks 1 and 5. Thirteen patients participated and were evaluable. One patient developed brain metastases and was replaced. No grade 3 or 4 toxicities and no dose-limiting toxicity occurred. One patient died due to progressive disease within 30 days of receiving the study drug. One patient developed HACA during the second six-week cycle. PK analysis showed mean whole body and blood alpha and beta half-lives of cG250 of 18.99 +/- 6.84 and 180.19 +/- 86.68 hours, respectively. All patients had cG250 tumour localization by gamma camera imaging in week 1 and 5. One patient had a complete response, nine patients had stable disease, and three had progressive disease. One patient received 11 six-week cycles of treatment with no toxicity or HACA. In conclusion, repeated intravenous doses of up to 50 mg/m(2) of cG250 are safe. Furthermore cG250 has a long half-life and targets clear cell RCC effectively.

A pilot study of monoclonal antibody cG250 and low dose subcutaneous IL-2 in patients with advanced renal cell carcinoma.

The chimeric monoclonal antibody cG250 recognizes the CAIX/MN antigen. cG250 induces antibody-dependent cellular cytotoxicity (ADCC) responses in vitro that can be enhanced by IL-2. We studied the effects of adding daily low-dose subcutaneous IL-2 to cG250 for treatment of clear cell renal cell carcinoma (RCC). The primary endpoints of the trial were toxicity and immunological effects (human anti-chimeric antibodies [HACA], ADCC, natural killer [NK] and lymphokine-activated killer cell [LAK] activity); secondary endpoints were cG250 biodistribution and pharmacokinetics (PK) and tumour response rates. Eligible patients had unresectable metastatic or locally advanced clear cell RCC with measurable or evaluable disease. Nine patients were treated with six doses of cG250 (10 mg/m(2)/week, first and fifth doses trace-labelled with (131)I), and 1.25 x 10(6) IU/m(2)/day IL-2 for six weeks. Treatment was generally well tolerated with no adverse events attributable to cG250. Two patients required a 50% dose reduction of IL-2 due to toxicity. No HACA was detected. (131)I-labeled cG250 showed excellent targeting of tumour deposits. (131)I cG250 PK: T(1/2)alpha 20.16 +/- 6.59 h, T(1/2)beta 126.21 +/- 34.04 h, CL 39.67 +/- 23.06 mL/h, Cmax 5.12 +/- 0.86 microg/mL, V(1) 3.88 +/- 1.05 L. IL-2 did not affect cG250 PK. A trend for increased percentage of circulating CD3-/CD16+CD56+ NK cells was observed. Some patients showed enhanced ADCC or LAK activity. No antitumour responses were observed. In conclusion, weekly cG250 with daily low-dose subcutaneous IL-2 is well tolerated. IL-2 does not influence cG250 biodistribution or increase HACA.

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 Le(y) antigen. EXPERIMENTAL DESIGN: Patients with advanced Le(y)-positive cancers received four infusions of hu3S193 at weekly intervals, with four dose levels (5, 10, 20, and 40 mg/m(2)). 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 40 mg/m(2) 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 (111)In-hu3S193 showed no evidence of any consistent normal tissue uptake, and (111)In-hu3S193 uptake was observed in cutaneous, lymph node, and hepatic metastases. Hu3S193 displayed a long serum half-life (T(1/2)beta = 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 Le(y)-expressing cancers.

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.

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 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 (T1/2beta) 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 x 10(-3) to 11.1 x 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.

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 T1/2beta 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.

Characterization of antigen-specific CD8+ T lymphocyte responses in skin and peripheral blood following intradermal peptide vaccination.

Immune responses to cancer vaccines are commonly tested by measuring cutaneous reactions to intradermal (i.d.) antigen. When well-characterized peptide epitopes are injected i.d., infiltrates of CD4+ and CD8+ T lymphocytes are frequently seen. In this study, we have further characterized T cells derived from vaccine-infiltrating lymphocyte (VIL) responses. We found that the infiltrates capable of producing IFN-gamma and cytolytic activity could recognize vaccine peptide, as well as antigen-positive melanoma cells. We studied antigen-specific T cell responses from VILs and peripheral blood in 10 patients who participated in a clinical trial. All patients received systemic Flt3 ligand (20 microg/kg/d) and i.d. peptides: Three NY-ESO-1 peptides, SLLMWITQCFL (157-167), SLLMWITQC (157-165), QLSLLMWIT (155-163); tyrosinase internal peptide YMDGTMSQV (368-376); Melan-A/MART-1 analogue peptide ELAGIGILTV (26-35, E27L substitution); and influenza matrix peptide GILGFVFTL (58-66). In 54 paired VIL and peripheral blood analyses, a good correlation was found between responses in skin and in blood. These cells could be rapidly expanded in a short-term assay and thus appear to be memory T cells. The demonstrated presence of antigen-specific T cells at vaccination sites validates this method of assessing the immune response to i.d. vaccines.

Immunological effects of chimeric anti-GD3 monoclonal antibody KM871 in patients with metastatic melanoma.

We conducted an open label dose-escalation phase I trial of chimeric anti-GD3 mAb KM871 in patients with metastatic melanoma. Patients were entered into one of five dose levels (1, 5, 10, 20, and 40 mg/m2) and received three infusions of KM871 at 2-wk intervals. A metastatic melanoma site was biopsied at day 7-10. Pharmacokinetics, immune function, and mechanism of action of KM871 were analysed. A total of 17 patients were entered into the trial; 15 were evaluable. KM871 had a serum half-life (T1/2-beta) based on ELISA of 10.39 +/- 1.12 d (mean +/- SD). Trough levels >1.0 microg/mL KM871 at 2 wk postinfusion were seen with the 10 mg/m2 and higher dose levels. There were no significant changes in white blood cell subsets or serum complement levels during KM871 treatment. KM871 was stable in vivo and maintained binding affinity and complement-dependent cytotoxicity (CDC) function up to 2 wk postinfusion. No significant trends in CDC or antibody-dependent cellular-cytotoxicity (ADCC) activity in patients were observed during treatment. Analysis of tumour biopsies demonstrated a significant increase in CD4+ T cell infiltrates compared to control patient tumours (P = 0.010), and in patients with either stable disease (2 patients) or a clinical partial response (1 patient) at restaging, a significant increase in CD3 and CD4 infiltrates in tumour over nonresponding patients was observed. The favourable immune properties of KM871, combined with this preliminary clinical data, indicate that KM871 has potential for the treatment of metastatic melanoma.

The impact of imiquimod, a Toll-like receptor-7 ligand (TLR7L), on the immunogenicity of melanoma peptide vaccination with adjuvant Flt3 ligand.

Dendritic cells (DCs) show promise as adjuvants in anticancer immunotherapeutic strategies. Flt3 ligand (FL) is a hematopoietic growth factor that increases the number of immature DCs in the blood and other tissues. We treated 27 patients with metastatic or high-risk resected melanoma with s.c. FL daily for 14 d in three 28 d cycles. Eighteen of these patients also received vaccination with influenza (Flu), Melan-A (Mel), tyrosinase (Tyr), and NY-ESO-1 peptides. To induce local DC maturation, 8 of the vaccinated patients had imiquimod, a Toll-like receptor-7 ligand (TLR7L), applied topically to their vaccine sites. Patients were monitored for clinical and hematological effects. Immune responses were assessed by cutaneous reactivity to vaccination and by the induction of peptide-specific CD8+ T-cells. Eight patients did not complete the protocol due to adverse events related to their cancer. The treatment was generally safe and well tolerated, although some patients developed clinically significant toxicities related to FL. FL induced increases in immature CD11c+ and CD123+ peripheral blood (PB) DCs. Other hematological effects included monocytosis, granulocytosis, and thrombocytosis, which were marked in some patients. Cutaneous reactions to peptide vaccination and circulating peptide-specific CD8+ T-cells were more frequent in imiquimod-treated patients. FL treatment of melanoma patients has pleiotropic clinical and hematological effects. In vivo maturation of FL-generated DCs using imiquimod may increase immune responses to tumor antigens.

Recombinant NY-ESO-1 protein with ISCOMATRIX adjuvant induces broad integrated antibody and CD4(+) and CD8(+) T cell responses in humans.

NY-ESO-1 is a "cancer-testis" antigen expressed in many cancers. ISCOMATRIX is a saponin-based adjuvant that induces antibody and T cell responses. We performed a placebo-controlled clinical trial evaluating the safety and immunogenicity of recombinant NY-ESO-1 protein with ISCOMATRIX adjuvant. Forty-six evaluable patients with resected NY-ESO-1-positive tumors received three doses of vaccine intramuscularly at monthly intervals. The vaccine was well tolerated. We observed high-titer antibody responses, strong delayed-type hypersensitivity reactions, and circulating CD8(+) and CD4(+) T cells specific for a broad range of NY-ESO-1 epitopes, including known and previously unknown epitopes. In an unplanned analysis, vaccinated patients appeared to have superior clinical outcomes to those treated with placebo or protein alone. The vaccine is safe and highly potent immunologically.

Immunodominant CD4+ responses identified in a patient vaccinated with full-length NY-ESO-1 formulated with ISCOMATRIX adjuvant.

There is increasing evidence showing the involvement of CD4(+) T cells in initiating and maintaining antitumor immune responses. NY-ESO-1 is expressed by various tumors but not normal tissues except testis. We conducted a cancer clinical trial by using full-length NY-ESO-1 protein formulated with ISCOMATRIX adjuvant and injected into patients intramuscularly. Autologous dendritic cells pulsed with NY-ESO-1 ISCOMATRIX in combination with overlapping synthetic peptides were used to identify immunodominant T cells from a vaccinated patient. We show here the identification and characterization of two novel CD4(+) T cell epitopes. T cells specific to these epitopes not only recognized autologous dendritic cells loaded with NY-ESO-1 but also NY-ESO-1-expressing tumor cell lines treated with IFN-gamma. One of the two responses identified was greater than the previously identified immunodominant HLA-DP4-restricted response and correlated with NY-ESO-1-specific CD8(+) T cell induction after vaccination. This T cell response was vaccinated in most patients who expressed HLA-DR2. This study has systematically surveyed patients vaccinated with full-length tumor antigen for a vaccinated CD4 helper T cell response.

Two phase I studies of low dose recombinant human IL-12 with Melan-A and influenza peptides in subjects with advanced malignant melanoma.

Preclinical studies have shown that low dose IL-12 can potentiate cytotoxic lymphocyte responses. Since previous trials have demonstrated significant toxicity from high dose recombinant human IL-12 (rhIL-12), we sought to determine an optimal biological dose for rhIL-12 at lower doses when combined with peptide antigens. Two studies were undertaken. The rhIL-12 was administered at doses of 0 (placebo), 10, 30 and 100 ng/kg, subcutaneously in one study and intravenously in the other. Apart from IL-12 dosing, the studies were identical. Subjects had evaluable stage III or IV melanoma which expressed Melan-A by RT-PCR or immunohistochemistry. Melan-A (26-35) (EAAGIGILTV) and influenza matrix (58-66) (GILGFVFTL) peptides were administered intradermally on weeks 1, 2, 3, 4 and 9. Twenty-eight subjects were enrolled, of whom 24 were evaluable for clinical and immunological responses. Therapy was well tolerated, the main adverse event being influenza-like symptoms. Immunological monitoring included the evaluation of cutaneous reactions and assays for antigen-specific T-cells. Clinical responses included a complete response in a subject with small volume subcutaneous disease, a partial response in a subject with hepatic metastases, and mixed responses in pulmonary, pleural and nodal disease. Biopsies of accessible tumors showed infiltration with CD4+ and CD8+ lymphocytes capable of lysing Melan-A peptide-pulsed targets in vitro. No clear dose-dependent effect of rhIL-12 could be determined. The rhIL-12 given either s.c. or i.v. was well tolerated at doses of 10-100 ng/kg. Clinical and immunological activity has been observed in this study where peptides were administered either with or without low dose rhIL-12.

A Phase I dose-escalation study of sibrotuzumab in patients with advanced or metastatic fibroblast activation protein-positive cancer.

PURPOSE: The purpose of this research was to determine the safety, immunogenicity, pharmacokinetics, biodistribution, and tumor uptake of repeat infusions of a complementarity-determining region grafted humanized antibody (sibrotuzumab) directed against human fibroblast activation protein (FAP). EXPERIMENTAL DESIGN: A Phase I open-label dose escalation study was conducted in patients with cancers epidemiologically known to be FAP positive. Patients were entered into one of four dosage tiers of 5, 10, 25, or 50 mg/m(2) sibrotuzumab, administered weekly for 12 weeks, with trace labeling with 8-10 mCi of (131)I in weeks 1, 5, and 9. RESULTS: A total of 26 patients were entered into the trial (15 males and 11 females; mean age, 59.9 years; age range, 41-81 years). Twenty patients had colorectal carcinoma, and 6 patients had non-small cell lung cancer. A total of 218 infusions of sibrotuzumab were administered during the first 12 weeks of the study, with 24 patients being evaluable. One patient received an additional 96 infusions on continued-use phase for a total of 108 infusions over a 2-year period, and 1 patient received an additional 6 infusions on continued use. There were no objective tumor responses. Only one episode of dose-limiting toxicity was observed. Therefore, a maximum tolerated dose was not reached. Treatment-related adverse events were observed in 6 patients during the infusional monitoring period. Four of the 6 patients, 3 of whom had associated positive serum human antihuman antibody, were removed from the study because of clinical immune responses. Gamma camera images of [(131)I]sibrotuzumab demonstrated no normal organ uptake of sibrotuzumab, with tumor uptake evident within 24-48 h after infusion. Analysis of pharmacokinetics demonstrated a similar mean terminal t(1/2) of 1.4-2.6 days at the 5, 10, and 25 mg/m(2) dose levels, and with a longer mean t(1/2) of 4.9 days at the 50 mg/m(2) dose level. CONCLUSION: Repeat infusions of the humanized anti-FAP antibody sibrotuzumab can be administered safely to patients with advanced FAP-positive cancer.