Mapping a sustainable approach: biosynthesis of lactobacilli-silver nanocomposites using whey-based medium for antimicrobial and bioactivity applications.

This study explores a sustainable approach for synthesizing silver nanocomposites (AgNCs) with enhanced antimicrobial and bioactivity using safe Lactobacillus strains and a whey-based medium (WBM). WBM effectively supported the growth of Lactobacillus delbrueckii and Lactobacillus acidophilus, triggering a stress response that led to AgNCs formation. The synthesized AgNCs were characterized using advanced spectroscopic and imaging techniques such as UV‒visible, Fourier transform infrared (FT-IR) spectroscopy, transmission electron (TEM), and scanning electron microscopy with energy dispersive X-ray analysis (SEM-Edx). Lb acidophilus-synthesized AgNCs in WBM (had DLS size average 817.2-974.3 ± PDI = 0.441 nm with an average of metal core size 13.32 ± 3.55 nm) exhibited significant antimicrobial activity against a broad spectrum of pathogens, including bacteria such as Escherichia coli (16.47 ± 2.19 nm), Bacillus cereus (15.31 ± 0.43 nm), Clostridium perfringens (25.95 ± 0.03 mm), Enterococcus faecalis (32.34 ± 0.07 mm), Listeria monocytogenes (23.33 ± 0.05 mm), methicillin-resistant Staphylococcus aureus (MRSA) (13.20 ± 1.76 mm), and filamentous fungi such as Aspergillus brasiliensis (33.46 ± 0.01 mm). In addition, Lb acidophilus-synthesized AgNCs in WBM exhibit remarkable free radical scavenging abilities, suggesting their potential as bioavailable antioxidants. These findings highlight the dual functionality of these biogenic AgNCs, making them promising candidates for applications in both medicine and nutrition.

A randomized, phase II trial of two dose schedules of carboplatin/paclitaxel/cetuximab in stage IIIB/IV non-small-cell lung cancer (NSCLC).

BACKGROUND: This trial investigated the efficacy and safety of weekly cetuximab combined with two different schedules of paclitaxel/carboplatin for stage IIIB/IV non-small-cell lung cancer (NSCLC). METHODS: A total of 168 patients with previously untreated stage IIIB/IV NSCLC were randomized to arm A, cetuximab (400 mg/m(2) day 1 followed by weekly 250 mg/m(2)) + paclitaxel (Taxol) (225 mg/m(2))/carboplatin (AUC6) day 1 every 3 weeks or arm B, same cetuximab regimen plus paclitaxel (100 mg/m(2)) days 1, 8, and 15 every 3 weeks and carboplatin (AUC6) day 1 every 4 weeks. Treatment continued for a four-cycle maximum. Patients with a complete response, partial response, or stable disease after four cycles could receive cetuximab 250 mg/m(2)/week until disease progression or unacceptable toxicity. The primary end point was to evaluate progression-free survival (PFS). RESULTS: Median PFS was 4.7 and 4.3 months for arms A and B, respectively (6-month PFS, 27.3% versus 30.9%). Median overall survival was 11.4 versus 9.8 months for arms A and B, respectively; estimated 1-year survival, 47.7% versus 39.3%; and objective response rate, 29.6% versus 25%. The regimen was well tolerated with rash and hematologic toxicity being most common. CONCLUSIONS: This study did not meet the prespecified benchmark of 35% 6-month PFS rate; both combination schedules of cetuximab plus paclitaxel/carboplatin were feasible and equivalent for treating advanced NSCLC.

Phase I trial of multiple large doses of murine monoclonal antibody CO17-1A. I. Clinical aspects.

Twenty-five patients with metastatic gastrointestinal adenocarcinoma received one to four infusions (400 mg) of murine monoclonal antibody CO17-1A. Eleven patients had mild gastrointestinal symptoms, and one had a transient flushing episode. Two of five who received three weekly infusions had readily reversible anaphylactic reactions at the time of the third infusion (day 15). There were no other toxic effects. One patient had a complete remission and is surviving at greater than 104 weeks, and four had stable disease. The median survival for the whole group was 57 weeks. In general, the antibody infusions were well tolerated but had modest antitumor effects.

Phase I trial of multiple large doses of murine monoclonal antibody CO17-1A. II. Pharmacokinetics and immune response.

Twenty-five patients with metastatic gastrointestinal adenocarcinoma received one to four infusions of large doses (400 mg) of murine monoclonal antibody CO17-1A (17-1A). The pharmacokinetics of 17-1A at the time of first, second, third, or fourth infusion were not statistically different; plasma half-lives were 15.0 +/- 1.7 hours (n = 5), 15.1 +/- 1.8 (n = 10), 25.3 +/- 6.2 (n = 3), and 14.4 +/- 1.8 (n = 5), respectively. Most patients had an antibody response to 17-1A, with peak levels occurring 15-22 days after infusion. The presence of serum antibody to 17-1A at the time of the second or third infusion did not significantly alter the pharmacokinetics of this large dose of antibody. Four of 25 patients failed to develop an antibody response, but this did not correlate with the amount of 17-1A administered. The administration of four doses of 400 mg over 1 week provided continuously circulating 17-1A for 10 days.

Evidence for the elevation of serum carcinoembryonic antigen and tumor-associated glycoprotein-72 levels in patients administered interferons.

Sera were collected from 111 patients diagnosed with adenocarcinoma or nonadenocarcinoma malignancies who received different schedules of interferon (IFN)-gamma or IFN-beta ser alone or in combination. Serum carcinoembryonic antigen (CEA) and tumor-associated glycoprotein-72 (TAG-72) antigen levels were measured to determine whether interferon could enhance the tumor shedding and, thereby, the serum level of either tumor antigen. Less than 10% of the sera samples from patients diagnosed with nonadenocarcinoma malignancies (e.g., hairy cell leukemia, melanoma) had positive titers of TAG-72 or CEA, and interferon neither increased nor resulted in the appearance of either tumor antigen in those sera. In contrast, 59.2% and 75.4% of the patients with adenocarcinoma had positive serum levels of TAG-72 and CEA, respectively, prior to interferon. IFN-gamma and IFN-beta ser alone or in combination significantly increased serum TAG-72 or CEA in approximately 65% of those patients. The results suggest that interferon administration to patients with adenocarcinoma can result in increased serum levels of selected tumor-associated antigens used in the diagnosis of malignancy. These preliminary findings may be important in the development of new strategies to obtain more sensitive tumor antigen serum assays for the diagnosis and monitoring for disease progression of adenocarcinoma.

Pharmacokinetics and immune response of 131I-chimeric mouse/human B72.3 (human gamma 4) monoclonal antibody in humans.

Chimeric B72.3, composed of the V-regions of murine B72.3 and the constant regions of human immunoglobulin G4 heavy and kappa light chain, was administered as a 131I-labeled conjugate to 12 patients with metastatic colon cancer. Seven of these patients had an antibody response after initial infusion, and the immune response was primarily directed to the murine V-region, although a small proportion of the antibody response was directed to topographical epitopes requiring the presence of both murine V-region and human CH-1 and kappa constant regions (neo-epitopes). The pharmacokinetics included a plasma disappearance curve best fit by a two-compartmental model with an alpha t 1/2 of 18 +/- 7 h and a beta t 1/2 of 224 +/- 66 h. A second infusion of the same dose of 131I-chimeric B72.3 was administered to four of these patients 8 wk after the first infusion. Two patients who had a high antibody response to initial infusion had an anamnestic antibody response, and the infused ch-B72.3 rapidly disappeared from the circulation with associated immune complexes and free 131I in the plasma. One patient with no initial antibody response had no antibody response and identical pharmacokinetics on second infusion. One patient with a modest transient antibody response to initial infusion had no antibody response on second infusion and a modest shortening of plasma circulation. Thus, the human immunoglobulin G4 isotype chimeric B72.3 monoclonal antibody has a plasma half-life 6 to 8 times as long as murine B72.3 and retains considerable immunogenicity in some patients which can adversely affect repetitive infusions.

A phase I clinical trial of murine monoclonal antibody D612 in patients with metastatic gastrointestinal cancer.

In a phase I study, 21 patients with metastatic adenocarcinoma of the gastrointestinal tract received the murine monoclonal antibody D612. This antibody is directed at a M(r) 48,000 antigen restrictively expressed on tumors of the gastrointestinal tract and to a limited degree on normal gastrointestinal mucosa. Patients received total doses of 10-180 mg/m2 administered as single or multiple doses of 1-100 mg/m2 over an 8-day period. Dose-limiting toxicity was secretory diarrhea. A single dose of 100 mg/m2 exceeded guidelines for maximal tolerated dose. Higher total doses were achieved in subsequent patients by using repeated administration of lower doses. Three of five patients receiving 60 mg/m2 for 3 doses (180 mg/m2 total dose) experienced grade 3 diarrhea and could not complete the prescribed course. The dose of 40 mg/m2 administered on days 1, 4, and 8 (total dose, 120 mg/m2) has been selected as the dose for phase II studies. The pharmacokinetics of D612 is best described by a one-compartment model with a mean t1/2 of 48 +/- 3 h (SEM). Eighteen of 21 patients developed human anti-mouse antibody (HAMA). Patients who developed high levels of HAMA demonstrated a more rapid clearance of the day 8 dose than those who developed low levels of HAMA. In all patients studied, a component of HAMA was directed at the D612 variable region. With one exception, serum from all patients with detectable antibody to the D612 variable region demonstrated anti-paratope reactivity. Thirty-four % of known metastatic sites demonstrated uptake of radiolabeled D612. There were no objective antitumor responses in this phase I trial. The antitumor effect of D612 in vitro has been shown to be potentiated by interleukin 2 and recombinant human macrophage colony-stimulating factor. A phase II study of D612 administered in combination with cytokines that enhance human effector function is presently ongoing.

Phase II trial of murine monoclonal antibody D612 combined with recombinant human monocyte colony-stimulating factor (rhM-CSF) in patients with metastatic gastrointestinal cancer.

In a Phase II study, 14 patients with metastatic gastrointestinal cancer received the mAb D612 (40 mg/m2, days 4, 7, and 11) in combination with recombinant human monocyte colony-stimulating factor [(rhM-CSF) 80 micrograms/kg/days 1-14]. The combined treatment was well tolerated and resulted in characteristic biological activity associated with each of the agents. Thus, 10 of 14 patients experienced D612-associated secretory diarrhea, which responded to the prostaglandin inhibitor Indomethacin in 5 of 7 patients. rhM-CSF therapy was associated with peripheral monocytosis (peak absolute monocyte count, 1444 +/- 394/mm3) and thrombocytopenia (nadir count, 78 +/- 10/mm3). Monocyte surface marker analysis revealed a high baseline expression of CD16+ cells in our patient population with an additional increase with rhM-CSF therapy. We observed a correlation between the degree of thrombocytopenia and the pretreatment CD16+ monocyte count. Of the plasma cytokines assayed, serum Neopterin demonstrated the most consistent increase during rhM-CSF therapy. There was a significant difference in the half-life of the first and last dose of D612 (35.8 +/- 2 versus 27 +/- 2.9 h; P < 0.05). Eleven of fourteen patients developed low-moderate levels of anti-D612 antibody. Despite the observed biological activity of both rhM-CSF and D612 and the previously described in vitro synergy, no clinical antitumor responses were observed in this Phase II study.

Phase I trial of the murine monoclonal anti-GD2 antibody 14G2a in metastatic melanoma.

In a phase I trial, 12 patients with GD2 antigen-positive metastatic melanoma received the murine anti-GD2 monoclonal antibody 14G2a. The monoclonal antibody was administered in four doses over an 8-day period with total dose ranging from 10 to 120 mg. All patients receiving greater than 10 mg of 14G2a experienced transient abdominal/pelvic pain during the antibody infusion. Five patients had a delayed extremity pain syndrome following the third and fourth antibody infusion. Four of the five patients developed neurological toxicity, including two patients with significant although reversible motor neuropathy. Two of the patients developed hyponatremia secondary to a syndrome of inappropriate antidiuretic hormone. All 12 patients developed high levels of human anti-14G2a antibody. The plasma half-life of 14G2a was 42 +/- 6 (SD) h. One patient each had a partial response, mixed response, and stable disease, respectively. The very modest antitumor activity accompanied by dose-limiting neurological toxicity at total doses greater than 80 mg may restrict the clinical utility of murine 14G2a.

Clinical use of a standard kit-preparation of radiolabeled monoclonal antibody 96.5 in the diagnostic imaging of metastatic melanoma.

We studied the efficiency of a standard-kit preparation using 1 mg 111In-labeled 96.5 monoclonal antibody in combination with 19 mg of unlabeled antibody in the diagnostic imaging of 27 patients with documented metastatic melanoma. Twenty-three of 26 patients (88%) demonstrated immunoscintigraphic localization of tumor. Of 104 metastatic sites previously documented by conventional studies, 62 (60%) were identified by immunoscintigraphy. A total of 77 sites demonstrated localization of radiolabeled antibody. Fifty-four (70%) corresponded to known sites of disease; eight sites (10%) were "discovered" by immunoscintigraphy and subsequently confirmed by conventional studies; 15 imaged sites (20%) could not be confirmed by conventional studies. Size and location of metastasis appear to be important features that influence imaging efficiency. Tumor size (greater than or equal to 2 cm v less than 2 cm) appears to be the statistical dominant determinant. The feasibility and potential clinical use of radioimmune imaging of tumors is discussed.

Phase I trial of the anti-Lewis Y drug immunoconjugate BR96-doxorubicin in patients with lewis Y-expressing epithelial tumors.

PURPOSE: We conducted a phase I clinical trial of BR96-Doxorubicin (BR96-Dox), a chimeric anti-Lewis Y (Le(Y)) monoclonal antibody conjugated to doxorubicin, in patients whose tumors expressed the Le(Y) antigen. The study aimed to determine the toxicity, maximum-tolerated dose, pharmacokinetics, and immunogenicity of BR96-Dox. PATIENTS AND METHODS: This was a phase I dose escalation study. BR96-Dox was initially administered alone as a 2-hour infusion every 3 weeks. The occurrence of gastrointestinal (GI) toxicity necessitated the administration of BR96-Dox as a continuous infusion over 24 hours and use of antiemetics and antigastritis premedication. Patients experiencing severe GI toxicity underwent GI endoscopy. All patients underwent restaging after two cycles. RESULTS: A total of 66 patients predominantly with metastatic colon and breast cancer were enrolled onto the study. The most common side effects were GI toxicity, fever, and elevation of pancreatic lipase. At higher doses, BR96-Dox was associated with nausea, vomiting, and endoscopically documented exudative gastritis of the upper GI tract, which was dose-limiting at a maximum dose of 875 mg/m(2) (doxorubicin equivalent, 25 mg/m(2)) administered every 3 weeks. Toxicity was reversible and generally of short duration. Premedication with the antiemetic Kytril (granisetron hydrochloride; SmithKline Beecham, Philadelphia, PA), the antacid omeprazole, and dexamethasone was most effective in ameliorating GI toxicity. A dose of 700 mg/m(2) BR96-Dox (doxorubicin equivalent, 19 mg/m(2)) every 3 weeks was determined to be the optimal phase II dose when administered with antiemetic and antigastritis prophylaxis. BR96-Dox deposition on tumor tissue was documented immunohistochemically and by confocal microscopy. At the 550-mg/m(2) dose, the half-life (mean +/- SD) of BR96 and doxorubicin was 300 +/- 95 hours and 43 +/- 4 hours, respectively. BR96-Dox elicited a weak immune response in 37% of patients. Objective clinical responses were seen in two patients. CONCLUSION: BR96-Dox provides a unique strategy to deliver doxorubicin to Le(Y)-expressing tumor and was well tolerated at doses of 700 mg/m(2) every 3 weeks. BR96-Dox was not associated with the typical side-effect profile of native doxorubicin and can potentially deliver high doses of doxorubicin to antigen-expressing tumors. A phase II study in doxorubicin-sensitive tumors is warranted.

Phase I study of anti--epidermal growth factor receptor antibody cetuximab in combination with radiation therapy in patients with advanced head and neck cancer.

PURPOSE: To evaluate the safety, pharmacokinetics, and efficacy of a chimeric anti-epidermal growth factor receptor monoclonal antibody, cetuximab, in combination with radiation therapy (RT) in patients with advanced squamous cell carcinoma of the head and neck. PATIENTS AND METHODS: We treated 16 patients in five successive treatment schedules. A standard dose escalation procedure was used; three patients entered onto the study at each dose level of cetuximab received conventional RT (70 Gy, 2 Gy/d), and the final three patients received hyperfractionated RT (76.8 Gy, 1.2 Gy bid). Cetuximab was delivered as a loading dose of 100 to 500 mg/m(2), followed by weekly infusions of 100 to 250 mg/m(2) for 7 to 8 weeks. Circulating levels of cetuximab during therapy were determined using a biomolecular interaction analysis core instrument. Human antichimeric antibody response was evaluated with a double-antigen radiometric assay. The recommended phase II/III dose was defined as the optimal cetuximab dose level based on the pharmacologic parameters and adverse events. RESULTS: The most commonly reported adverse events were fever, asthenia, transaminase elevation, nausea, and skin toxicities (grade 1 to 2 in most patients). Skin toxicity outside of the RT field was not strictly dose-dependent; however, grade 2 or higher events were observed in patients treated with higher dose regimens. There was one grade 4 allergic reaction. Most acute adverse effects were associated with RT (xerostomia, mucositis, and local skin toxicity). No antibodies against cetuximab were detected. All patients achieved an objective response (13 complete and two partial remissions). CONCLUSION: Cetuximab can be safely administered with RT. The recommended dose for phase II/III studies is a loading dose of 400 to 500 mg/m(2) and a maintenance weekly dose of 250 mg/m(2).

Enhanced apoptosis with combination C225/radiation treatment serves as the impetus for clinical investigation in head and neck cancers.

PURPOSE: Epidermal growth factor receptor (EGFr) is overexpressed in a majority of head and neck squamous cell carcinomas, and this overexpression is associated with a poor prognosis. Therefore, EGFr has become the target of investigations aimed at disabling the receptor to determine whether this process leads to improved tumor kill with conventional treatment. MATERIALS AND METHODS: C225 is an anti-EGFr monoclonal antibody that inhibits receptor activity by blocking the ligand binding site. A panel of human head and neck squamous cell carcinoma cell lines was used to study the combination of C225 and radiation. RESULTS: It was determined that the combination of C225 (5 microgram/mL) delivered simultaneously with radiation (3 Gy) resulted in a greater decrement in cellular proliferation than either treatment alone. This reduction in proliferation correlated with reduced EGFr tyrosine phosphorylation and a reduction in phosphorylated signal transducer and activator of transcription-3 (STAT-3) protein (known to protect cells from apoptosis). Also, the decrement in proliferation correlated with increased apoptotic events, thereby indirectly linking C225/radiation-induced regulation of STAT-3 protein to apoptosis. CONCLUSION: This preclinical work serves as important support for the ongoing clinical investigation of C225 and radiotherapy for patients with head and neck carcinomas. The initial results of these clinical studies have been promising.

Phase I trial of a recombinant vaccinia virus encoding carcinoembryonic antigen in metastatic adenocarcinoma: comparison of intradermal versus subcutaneous administration.

The principal objectives of this trial were twofold: (a) to examine the safety and relative efficacy of intradermal needle injection versus s.c. jet administration of a carcinoembryonic antigen (CEA)-encoding recombinant vaccinia virus (rV-CEA) over a limited dose range and (b) to evaluate CEA-specific immune responses or antitumor effects induced by rV-CEA vaccination. Patients were randomly assigned to one of two groups, depending upon the technique of vaccine administration. All 20 patients received two doses of 10(7) or 10(8) pfu of rV-CEA at a 4-week interval. Toxicity was limited to modest local inflammation at the inoculation site as well as low-grade fever and increased fatigue, each affecting fewer than 20% of the patients. No evidence of CEA-specific lymphoproliferation, interleukin 2 release, delayed-type hypersensitivity, or antibody response was observed. Thus, the efficacy comparison between the two administration techniques was based upon the induction of immune responses to the vaccinia virus vector. Both techniques induced vaccinia-specific lymphoproliferation, interleukin 2 release, and antibody responses of comparable magnitude and frequency as well as protected 80% of patients against pustule formation following vaccinia scarification. Thus, there is no compelling reason to recommend one administration technique over the other based upon toxicity or efficacy. We have selected s.c. jet injection for subsequent trials of rV-CEA based on the ability to accommodate larger injection volumes, enhanced standardization between clinicians, and avoidance of needles that could transmit the vaccine or blood-borne pathogens to health care workers. We recommend use of 10(8) pfu doses for subsequent trials of recombinant vaccinia virus vaccines based upon the favorable toxicity profile and more consistent local pustule formation indicative of an adequate inoculation of live virus. No objective clinical responses to the rV-CEA vaccine were observed among this population of patients with widely metastatic adenocarcinoma.

A pilot study of the anti-CD20 monoclonal antibody rituximab in patients with refractory immune thrombocytopenia.

We conducted a prospective pilot phase I/II clinical trial to evaluate the toxicity and response rate of the chimeric anti-CD20 monoclonal antibody, rituximab (Rituxan; Genentech, Inc, South San Francisco, CA, and IDEC Pharmaceutical Corporation, San Diego, CA), in the treatment of patients with immune thrombocytopenic purpura. Patients with a clinical diagnosis of idiopathic thrombocytopenic purpura who had failed corticosteroid therapy and whose platelet count was less than 75,000/microL were eligible for the study. Rituximab was administered in a dose-escalation fashion using doses ranging from 50 to 375 mg/m2 weekly for 4 weeks. Thirteen patients have been enrolled on the trial to date and 12 have completed the full course of treatment. No unusual toxicity was noted in this patient population. None of the three patients at the lowest dose level achieved a clinical response. Three of nine patients (30%) who have received rituximab at doses close or equal to the full dose have shown an objective clinical response (two complete responses, one partial response). The study is currently ongoing, and conclusions regarding the overall response rate, clinical parameters that influence response, surrogate markers of response, and the underlying mechanism of response remain to be addressed. The current study should provide answers to a number of important questions regarding the role of rituximab in the treatment of this and other autoimmune disorders.

Phase I trial of iodine-131-chimeric B72.3 (human IgG4) in metastatic colorectal cancer.

Twelve patients with metastatic colorectal cancer participated in a Phase I trial of 131I-labeled chimeric B72.3 (human IgG4). Consecutive groups of patients received 18 mCi/m2, 27 mCi/m2 and 36 mCi/m2. No acute side effects related to antibody administration were noted. Bone marrow suppression was the only side effect; it was dose-dependent and correlated with whole-body radiation dose estimates. The lowest dose level produced no marrow suppression, whereas 27 mCi/m2 resulted in Grade 1 and 2 marrow suppression in two of three patients. The maximum tolerated dose was 36 mCi/m2 with all six patients at this dose level having at least Grade 1 and two patients with Grade 3 and 4 marrow suppression. Eight of 12 patients had radioimmune imaging of tumor sites at 5-22 days. Seven patients had an antibody response to initial infusion. On retreatment, whole-body kinetics and imaging were altered for patients with a high anti-ch-B72.3 response. Thus, chimeric B72.3 (IgG4) has limited utility as a means of delivering multiple therapeutic doses of 131I in the majority of patients; alternative strategies including second generation anti-TAG-72 monoclonal antibodies, other radioisotopes and other chimeric human isotypes will need to be pursued.

Correlation of toxicity with treatment parameters for 131I-CC49 radioimmunotherapy in three phase II clinical trials.

Analyses were performed on 40 patients with TAG-72 expressing metastatic cancer who were entered into three phase II clinical trials. The dose selected was the maximum tolerated dose in phase I studies. Patients all had unresectable metastatic colon or prostate cancer and had recovered from prior therapies. Patients in trials #1 and #2 received 75 mCi/m2 131I-CC49 antibody whereas those in trial #3 received a total of 75 mCi/m2 with equal amounts of 131I-CC49 and 131I-COL-1. The three trials have resulted in a reproducible degree of reversible marrow suppression; 72.5% of patients experienced moderate or severe toxicity. Comparisons were made between demographic, clinical and pharmacokinetical variables and the grade of WBC toxicity, platelet toxicity and the sum of the two as total toxicity. Whole body radiation dose had a statistically significant relationship with platelet toxicity (r = 0.38, p = 0.015) and total toxicity (r = 0.34, p = 0.035). The bone marrow radiation dose is significantly related to all toxicity indicators with correlation coefficients with WBC and platelet toxicities of 0.47 (p = 0.002) and 0.34 (p = 0.033), respectively. Plasma half-life had the strongest correlation with WBC toxicity and combined toxicities. Multivariate models were developed to help describe the simultaneous effect of these variables on toxicity. The results show that the MTD dose was safely given to patients who varied in age, disease burden and degree of marrow compromise. This supports the contention that a fixed dose of radiolabeled antibody per body mass or m2 can be given to a diverse group of non-lymphoma patients with a predictable toxicity range.

A pilot trial of Vitaxin, a humanized anti-vitronectin receptor (anti alpha v beta 3) antibody in patients with metastatic cancer.

The angiogenic response of a progressing malignancy is characterized by a shift in the balance of stimulatory and inhibiting factors of angiogenesis. Recognition of the regulated steps in tumor angiogenesis provides unique targets for developing anti-tumor therapy. Vitaxin is a humanized monoclonal antibody, which has specificity for the integrin alpha v beta 3 (vitronectin receptor). This antibody can impair the vascular response of endothelial cell growth factors in vitro and inhibit tumor cell mediated angiogenesis in pre-clinical animal models. Patients with metastatic cancer who failed standard therapy received intravenous doses of 10, 50 or 200 mg in cohorts of three patients. The unlabeled dose of Vitaxin was infused on days 0 and 21 of a treatment cycle. All patients received a pre-therapy imaging dose of 1 mg of Tc-99m Vitaxin with gamma camera imaging studies. There was no significant toxicity noted in these three dose levels. There were no objective anti-tumor responses. Three patients received two cycles of therapy and had stable disease at day 85 when taken off study. Radioimaging of tumor vasculature was unsuccessful although one patient with alpha v beta 3 positive melanoma had imaging of tumor sites. There was no immune response to Vitaxin in any patient. Patients receiving 10 mg doses of Vitaxin had poor plasma recovery of injected doses and brief circulation in plasma. Doses of 50 and 200 mg had plasma recovery that better approximated the predicted levels in plasma and circulation half-lives of approximately 7 days. This data suggests that an every three-week schedule of Vitaxin at doses of 200 mg (2.5-3.5 mg/kg) can maintain circulating levels of antibody with little or no toxicity. Future studies will be challenged to define anti-tumor activity in malignancy or appropriate surrogates of anti-tumor effect and explore escalating doses and alternate schedules of administration.

Combined modality therapy of A431 human epidermoid cancer using anti-EGFr antibody C225 and radiation.

BACKGROUND: Monoclonal antibodies (mAb) to epidermal growth factor receptor (EGFr) inhibit tumor cell proliferation and enhance cytotoxicity of chemotherapeutic agents. The purpose of this study was to investigate the interaction of the anti-EGFr antibody C225 combined with radiotherapy (RT) on EGFr expressing A431 human epidermoid cancer cells. METHODS: Cell proliferation, apoptosis, EGFr expression and phosphorylation, and clonogenic survival were assayed in vitro. A431 tumor growth inhibition and immunohistochemistry analysis of EGFr expression and apoptosis were assessed in vivo. RESULTS: C225 plus RT produced greater inhibition of A431 cell proliferation than C225 or RT alone which was corroborated by enhanced apoptosis. Similar clonogenic survival occurred following the addition of C225 to RT, although colonies were smaller in the presence of C225. C225 produced inhibition of EGF-induced phosphorylation of EGFr without concurrent down-regulation of surface receptor, which was not altered by RT. Combined treatment of mice bearing tumors demonstrated enhancement of complete regressions, reduction in time to tumor size doubling, and prolongation of survival. Significant apoptosis occurred in xenograft tumors treated with C225 with or without RT. CONCLUSIONS: These data demonstrate an interaction between C225 and RT. C225-mediated apoptosis and inhibition of EGFr phosphorylation may be critical in the interaction. Studies to define the precise influence of combined modality treatment on the EGFr signal transduction cascade need to be pursued. The combination of growth factor receptor antibodies and RT has potential application in clinical oncology.

Advances in monoclonal antibody therapy of cancer.

Tumor-associated antigens can be seen as unique targets for the delivery of anti-cancer therapy. Monoclonal antibodies directed at such antigens are increasingly being seen as important biologic reagents that will complement the group of existing cytotoxic drugs. This report briefly overviews recent advances in the field of monoclonal antibody therapy of cancer and provides insight regarding the promises and limitations of this novel therapeutic approach.