A Pharmacokinetic and Safety Study of Trebananib, an Fc-Fusion Peptibody, in Patients With Advanced Solid Tumors and Varying Degrees of Renal Dysfunction

Clearance of trebananib (AMG 386), a 64-kD antiangiogenic peptibody, has been associated with estimated glomerular filtration rate (eGFR). We prospectively evaluated trebananib pharmacokinetics and safety/tolerability in advanced solid tumor patients with varying degrees of renal function. Patients were assigned to normal renal function, mild, moderate, or severe renal dysfunction cohorts based on eGFR, received trebananib 15 mg/kg i.v. weekly, and underwent week 1 and week 5 pharmacokinetic and weekly safety assessments. For 28 patients, trebananib clearance decreased from normal renal function (1.52 mL/hr/kg), to mild (1.20 mL/hr/kg), moderate (0.79 mL/hr/kg), and severe (0.53 mL/hr/kg) renal dysfunction (P ≤ 0.001). Treatment-related adverse events showed no association with clearance. Trebananib clearance was proportional to eGFR and unrelated to pretreatment protein excretion. These data confirm a role for renal clearance of a recombinant peptibody with molecular weight <69 kD and support a longer dosing interval for patients with severe renal dysfunction.

Sublethal concentrations of gemcitabine (2′,2′-difluorodeoxycytidine) alter mitochondrial ultrastructure and function without reducing mitochondrial DNA content in BxPC-3 human pancreatic carcinoma cells

2′,2′-Difluorodeoxycytidine (gemcitabine), a pyrimidine nucleoside analog, is used therapeutically in the treatment of pancreatic, non-small cell lung, and breast cancer. The cytotoxic effect of gemcitabine is thought to be due to masked chain termination after the triphosphorylated anabolite of the drug is incorporated into nascent DNA strands. We tested the hypothesis that sublethal concentrations of gemcitabine inhibit DNA polymerase γ and reduce mitochondrial DNA content in BxPC-3 and MOLT-4 cell lines, and we used 2′,3′-dideoxycytidine, a known inhibitor of DNA polymerase γ as a positive control. The 6-day BxPC-3 cell growth IC50 for gemcitabine and 2′,3′-dideoxycytidine was 0.003 μM (SD ± 0.0005) and 14.5 μM (SD ± 4.7), respectively, and in MOLT-4 cells was 0.002 μM (SD ± 0.001) and 0.86 μM (SD ± 0.23), respectively. These drug concentrations were anti-proliferative but non-cytotocidal. Electron photomicrographic studies showed deranged mitochondrial cristae patterns in BxPC-3 cells treated with either gemcitabine or 2′,3′-dideoxycytidine for 6 days. Mitochondrial oxidative phosphorylation dysfunction was observed as reflected by increased lactate concentration in the media of cells exposed to gemcitabine, but to a much greater extent in cells exposed to 2′,3′-dideoxycytidine. PCR analysis showed that gemcitabine did not reduce mitochondrial DNA content in either BxPC-3 or MOLT-4 cells, but 2′,3′-dideoxycytidine did. The effect of gemcitabine on mitochondrial ultrastructure and function did not concomitantly yield a reduction in mitochondrial DNA content. Therefore, the molecular target(s) by which gemcitabine and 2′,3′-dideoxycytidine produce mitochondrial abnormalities in these cells appear to be different.

Phase II study of oral docetaxel and cyclosporine in canine epithelial cancer

The goal of the current study was to determine the efficacy of oral docetaxel in combination with cyclosporine in the treatment of canine epithelial cancer. Requirements for eligibility were histological confirmation of epithelial neoplasia, measurable disease, no chemotherapy treatment within 2 weeks, and a life expectancy of ≥ 3 months. Fifty-one dogs were enrolled. All dogs received 1.625 mg kg(-1) of docetaxel with 5 mg kg(-1) of cyclosporine (DT/CSA) by gavage. Ten dogs had progressive disease at 2 weeks, one dog died, and one dog was withdrawn from the study. Thirty-nine dogs were given a second dose of DT/CSA, three each receiving a third or fourth dose. Eight dogs had a dose reduction (1.5 mg kg(-1)) and six dogs had treatment delays primarily for gastrointestinal toxicity. The overall response rate was 16.7% (8/48 had a partial response there were no complete responses). The highest response rate was seen in dogs with oral squamous cell carcinoma (50%; 6/12).

An evaluation of the drug interaction potential of pazopanib, an oral vascular endothelial growth factor receptor tyrosine kinase inhibitor, using a modified Cooperstown 5+1 cocktail in patients with advanced solid tumors

Pazopanib, an oral inhibitor of vascular endothelial growth factor receptor, platelet-derived growth factor receptor, and c-kit kinases, inhibits multiple cytochrome P450 (CYP450) enzymes in vitro. This study in patients with advanced cancer evaluated the effect of pazopanib on CYP450 function by comparing the pharmacokinetics of CYP-specific probe drugs in the presence and absence of pazopanib. The probes used included midazolam (CYP3A specific), warfarin (CYP2C9 specific), omeprazole (CYP2C19 specific), caffeine (CYP1A2 specific), and dextromethorphan (CYP2D6 specific). The estimated ratios of the geometric means (90% confidence interval (CI)) for the area under the curve to the last measurable point (AUC(0-t)) for these probe drugs with/without pazopanib were as follows: midazolam, 1.35 (1.18-1.54); omeprazole, 0.81 (0.59-1.12); caffeine, 1.00 (0.77-1.30); and S-warfarin, 0.93 (0.84-1.03). The geometric least-squares (LS) mean ratio of urine dextromethorphan:dextrorphan ranged from 1.33 (0-4-h interval) to 1.64 (4-8-h interval). The data suggest that pazopanib is a weak inhibitor of CYP3A4 and CYP2D6 and has no effect on CYP1A2, CYP2C9, and CYP2C19 in patients with advanced cancer.

A phase I study of intravenous (IV) milataxel in combination with carboplatin in adult patients with advanced malignant solid tumors

e13525

Background: Milataxel (MXL) is a novel taxane with activity in human xenograft models against tumors resistant to paclitaxel. The primary objective of this study was to determine the MTD when MXL was given intravenously in combination with a fixed dose (AUC=6) of carboplatin (C) every 21 days in subjects with advanced malignant solid tumors. Secondary objectives were to (i) assess the safety and tolerability of the combination (ii) define the pharmacokinetics of MXL and C when given in combination (iii) obtain preliminary information on the antitumor activity of MXL+C. Methods: Key subject eligibility criteria included: adult pts with refractory malignant tumors, ECOG PS <3 and adequate hematologic, hepatic and renal function. PK data was obtained on day 1 for MXL and both free and bound platinum. Results: 11 pts (median age 60; 2 F,9 M) were treated. MXL was dose escalated in three cohorts (15, 20 and 25 mg/m2). Three patients were treated at 15 mg/m2 of MXL without a DLT. At the 25 mg/m2 dose of MXL there were two DLT's out of the 4 pts enrolled at this dose (1 pt - grade 3 febrile neutropenia, grade 4 thrombocytopenia; 1 pt - grade 4 ANC, grade 4 thrombocytopenia). At the 20 mg/m2 dose of MXL there were two DLT's out of the 4 pts enrolled at this dose with both pts having grade 4 ANC. The MTD and the recommended Phase II dose of MXL was 15 mg/m2 plus C (AUC= 6). The median number of cycles administered was 3 (range 1–16). The most frequent grade 3 or 4 treatment emergent adverse events were neutropenia (82%), leukopenia (55%), pancytopenia (27%), asthenia (18%), generalized edema (18%), thrombocytopenia (18%), anemia (18%), confusion (18%), and dyspnea (18%). One pt in the MTD cohort with cholangiocarcinoma had a PR. This patient received 16 cycles of therapy and had a response duration of 378 days and a TTP of 406 days. PK data (n=9) showed the elimination half-life of MXL ranged from 26 to 110 h, and that for free and total platinum were as would be predicted for C monotherapy. Conclusions: The MTD of MXL was 15 mg/m2 IV per three week cycle when combined with carboplatin (AUC= 6). One patient with a cholangiocarcinoma had a sustained PR for 378 days.

No significant financial relationships to disclose.

Aplidin synergizes with cytosine arabinoside: functional relevance of mitochondria in Aplidin-induced cytotoxicity

Aplidin (plitidepsin) is a novel marine-derived antitumor agent presently undergoing phase II clinical trials in hematological malignancies and solid tumors. Lack of bone marrow toxicity has encouraged further development of this drug for treatment of leukemia and lymphoma. Multiple signaling pathways have been shown to be involved in Aplidin-induced apoptosis and cell cycle arrest in G1 and G2 phase. However, the exact mechanism(s) of Aplidin action remains to be elucidated. Here we demonstrate that mitochondria-associated or -localized processes are the potential cellular targets of Aplidin. Whole genome gene-expression profiling (GEP) revealed that fatty acid metabolism, sterol biosynthesis and energy metabolism, including the tricarboxylic acid cycle and ATP synthesis are affected by Aplidin treatment. Moreover, mutant MOLT-4, human leukemia cells lacking functional mitochondria, were found to be resistant to Aplidin. Cytosine arabinoside (araC), which also generates oxidative stress but does not affect the ATP pool, showed synergism with Aplidin in our leukemia and lymphoma models in vitro and in vivo. These studies provide new insights into the mechanism of action of Aplidin. The efficacy of the combination of Aplidin and araC is currently being evaluated in clinical phase I/II program for the treatment of patients with relapsed leukemia and high-grade lymphoma.

Pharmacokinetic (PK) and phase I study of sorafenib (S) for solid tumors and hematologic malignancies in patients with hepatic or renal dysfunction (HD or RD): CALGB 60301

3538

Background: We sought to characterize the PK and determine a tolerable dose of S in patients with HD or RD. Methods: Patients with performance status 0–2 and pathologically proven solid tumors, multiple myeloma, or non-Hodgkin’s lymphoma, for whom standard therapy was exhausted, were assigned to one of 9 cohorts: [1] Bilirubin (B) =ULN and SGOT =ULN and creatinine clearance (CC) =60 ml/min; [2] B > ULN but = 1.5 x ULN and/or SGOT > ULN; [3] CC between 40 and 59 mL/min; [4] B > 1.5 x ULN to = 3 x ULN (any SGOT); [5] CC between 20 and 39 mL/min; [6] B > 3 x ULN to 10 x ULN (any SGOT); [7] CC < 20 mL/min; [8] albumin < 2.5 mg/dL (any B/ SGOT); and [9] hemodialysis. S was administered po as a 400 mg test dose on day 1 with blood sampled before and 1, 2, 3, 4, 6, 24, and 168 hrs afterwards for PK. Total S concentrations were fit to a 2-compartment model and population parameters from previous studies were utilized. On day 8, continuous daily po S started with dose escalation in groups of at least 3 evaluable patients. Dose-limiting toxicity (DLT) by day 29 was defined as: grade 4 neutrophils or platelets; B = 1.5 x baseline in HD and = 2.5 x ULN in RD; CC reduction by > 20 mL/min in RD and >10 mL/min in HD; grade = 3 nausea/vomiting/diarrhea despite optimal supportive care; or any other grade = 3 non-hematologic toxicity. Results: Between 1/05 and 12/06, 146 patients (target 150) were registered but 12 never started therapy. With the exception of cohorts 6 and 7, at least 12 patients per cohort were evaluable. The dose level in each cohort with DLT in less than one third of patients was: [1] 400 mg bid; [2] 400 mg bid; [3] 400 mg bid; [4] 200 mg bid; [5] 200 mg bid; [6] not even 200 mg every third day tolerable; [7] n/a; [8] 200 mg qd; and [9] 200 mg qd. All DLT was non-hematologic: 9 of 12 events in patients with HD were increase in B; other DLT included abdominal pain, rash, fatigue, nausea/vomiting, hand-foot syndrome, congestive heart failure, diarrhea, hemorrhage, and hypertension. PK data are available for 51 patients. Apparent S clearance was: highly variable, median 5.69 (range 1.27 - 19.98) L/hr; not related to age, body weight, or sex; and not different among cohorts. Conclusions: Apparent S clearance does not depend on cohort. We propose the above empiric starting doses by cohort.

No significant financial relationships to disclose.

Two cases of rapid onset Parkinson's syndrome following toxic ingestion of ethylene glycol and methanol

Ethylene glycol and methanol are toxic alcohols commonly found in a variety of commercial products. We report two cases, one associated with ethylene glycol and one with methanol poisoning, which both led to acute hemorrhagic necrosis of the basal ganglia and resulted in acute Parkinson's syndrome. It is unlikely that oxalate crystal deposition is the only mechanism for such basal ganglia necrosis, because similar findings were seen following methanol intoxication. We discuss other possible mechanisms that may contribute towards this unusual neurotoxicity. Both of our patients survived their toxic ingestions, but then developed acute Parkinson's syndrome within 10 days of the ingestion. However, the patient who ingested methanol developed respiratory muscle stiffness/weakness, which responded poorly to anti-Parkinsonian drug therapy. Treatment with carbidopa/levodopa improved cogwheel rigidity and bradykinesia in both patients. We conclude that acute Parkinsonism is one of the lesser-recognized devastating complications of both ethylene glycol and methanol poisoning.

American Board of Clinical Pharmacology fellowship training and certification in clinical pharmacology: educational value and future needs for the discipline

Currently, the training and education of young clinical pharmacologist who represent the future of our discipline rest almost entirely on institutions/organizations with established and productive fellowship training programs. Here, we discuss the role of the American Board of Clinical Pharmacology (ABCP) in accrediting fellowship training programs and certifying individual clinical pharmacologists. We also explore how ABCP certification adds value to both individual trainees and the discipline in the evolving world of clinical therapeutics and research in human pharmacology.

Phase I and pharmacokinetic evaluation of the combination of orally administered docetaxel and cyclosporin A in tumor-bearing cats

Intravenously administered docetaxel (DT) is problematic in cats because of the requirement for premedication to ameliorate acute vehicle-induced hypersensitivity reactions. Previously we have revealed that therapeutic plasma concentrations of DT can be achieved in normal and tumor-bearing dogs when DT is administered PO in combination with oral cyclosporin A (CSA). The purpose of this study was to identify the maximally tolerated dosage and characterize the pharmacokinetic disposition of oral DT combined with CSA in cats with tumors. Eighteen tumor-bearing cats were enrolled in this phase I dose escalation and pharmacokinetic study. DT was administered by gavage with CSA (5 mg/kg) twice over a 3-week period. The starting dose of DT was 1.0 mg/kg. Based on the clinical toxicity profile, with gastrointestinal adverse effects and hematologic toxicity the maximal tolerated dose of oral DT was 1.75 mg/kg in combination with 5 mg/kg CSA. Additional studies are necessary to determine the efficacy of DT/CSA in cats with epithelial tumors.

A phase I study of YM155, a novel survivin suppressant, administered by 168 hour continuous infusion to patients with advanced solid tumors

3014

Background: Survivin is one of the family of inhibitor of apoptosis proteins (IAP) that suppresses apoptosis through inhibition of caspases and procaspases. Survivin is selectively expressed in most solid tumors but not normal tissues. In a PC-3 cell model YM155 inhibited survivin mRNA transcription and survivin protein expression and showed potent (nM) anti-proliferative activity in preclinical models including tumor regressions. Methods: The objectives were to determine the maximum tolerated dose (MTD) of 168 hour continuous infusion of YM155 every 3 weeks, to evaluate toxicity, characterize the pharmacokinetics and observe anti-tumor activity. Standard 3+3 dose escalation scheme was utilized. Additional pts were added to fully characterize toxicities at the MTD. Pharmacokinetic sampling was performed during cycles 1 and 2. Results: 41 pts (M/F: 31/10, median age 61, range 28–78) with performance status of 0–2 were enrolled into 4 dose cohorts [1.8 mg/m2/day (N = 8), 3.6 (6), 6.0 (2) and 4.8 (25)]. Most common tumor types were prostate (9), NHL (5), and colorectal (5). 2/2 pts experienced DLTs at 6.0 (renal tubular necrosis with grade 3 mucositis and increased serum creatinine), thus the MTD was 4.8 mg/m2/day. The most frequent AEs were: pyrexia, arthralgia, nausea, fatigue and diarrhea. The most common grade 3 or 4 drug related AEs were: mucosal inflammation (N = 2, 4.9%) and increased INR (N = 2, 4.9%). At MTD, the median clearance was 47 L/hr with a median steady state concentration of 7.5 ng/mL and a median terminal half-life of 22 hours. Two pts with chemotherapy refractory intermediate grade NHL had marked reduction of lymph nodes including one that was durable (PR reviewed independently). This pt went onto BMT and was in remission at the time of this submission. Two HRPC pts exhibited PSA response (> 50% reduction). Conclusions: YM 155, the first survivin inhibitor, was well tolerated, had a MTD of 4.8 mg/m2/day × 7 days and exhibited provocative anti-tumor activity in 4 pts that warrant broad phase II evaluation.

No significant financial relationships to disclose.

First-in-human phase-I pharmacokinetic trial of NS-9, a liposomal poly(I):poly(C), in patients with liver metastases from various primary cancers

13016

Background: NS-9 is a complex of poly-inosinate [poly(I)] and poly-cytidylate [poly(C)] in a cationic liposome and is active in vitro and in vivo. Objectives: to determine the tolerability, safety, and maximal tolerated dose (MTD), and pharmacokinetics of NS-9 by 1 hr IV infusion, given daily x5 q 28 days. Methods: A phase I dose escalation study was undertaken in patients with liver metastases from solid tumors. Eligible patients were adults with ECOG PS 0–1 and no recent chemotherapy (≥ 4 wks prior). Dose cohorts studied were 0.1, 0.15, 0.2, 0.3 and 0.4mg/m2. Results: 18 patients were enrolled (13M:5F) median age 58 (range 21 to 77 yrs). Tumor types included neuroendocrine (8), and ocular melanoma (1), gastric (1), GE junction (1), esophageal (2), and colorectal (5) carcinomas. Two of three patients treated at the first dose level (0.4 mg/m2) had grade 3/4 reversible lipase elevation with or without acute pancreatitis, a dose limiting toxicity (DLT). De-escalation to doses ranging from 0.1 to 0.2 mg/m2/day was with no DLT. At 0.3 mg/m2 two of three patients treated had a DLT (neutropenia and thrombocytopenia). The MTD was determined at 0.2 mg/m2. Common toxicities included pyrexia, chills, nausea, fatigue, abdominal pain, myalgia, anorexia, sweating, neutropenia, thrombocytopenia, and elevated glucose, amylase, and LFTs. Pharmacokinetics showed rapid elimination (T1/2 ranged from 2.4 to 5.0 hours) without accumulation after multiple doses. 1 patient (esophageal Ca) had a PR in the target lesions in the liver. Conclusions: The MTD is 0.2 mg/m2/day with a hint of antitumor activity. NS-9 should be pursued in phase-II studies.

No significant financial relationships to disclose.

Phase I study of erlotinib (E) for solid tumors in patients with hepatic or renal dysfunction (HD or RD): CALGB 60101

3026

Background: We sought to determine a tolerable dose and characterize the pharmacokinetics (PK) of E in patients with HD or RD. Methods: Patients with biopsy-proven solid tumors that commonly express EGFR, refractory to or without available standard therapy, performance status 0–2, and without biliary or renal obstruction were assigned to one of 3 cohorts (C): C1, AST ≥ 3 × ULN but no RD; C2, direct bilirubin 1–7 mg/dl but no RD; C3, creatinine 1.6–5.0 mg/dl but no HD. After slow accrual of 3 patients, an amended C1 for albumin < 2.5 g/dl accrued 3 additional patients. E was administered po daily in groups of at least 3 evaluable patients in escalating doses of 50, 75, 100, 150 mg starting with 50 mg in HD and 75 mg in RD. Patients had to take E for at least 4 weeks to be considered evaluable for toxicity unless dose-limiting toxicity (DLT) occurred sooner. DLT was defined as: grade 4 neutrophils or platelets; bilirubin ≥ 1.5 × baseline in C1/2 and ≥ 2.5 × ULN in C3; creatinine ≥ 2 × ULN in C1/2 and ≥ 2.5 × baseline in C3; grade ≥ 3 nausea,vomiting,diarrhea despite optimal supportive care; or any other grade ≥ 3 non-hematologic toxicity. Blood samples were obtained before and 1, 2, 3, 4, 6, 24 hrs after the first dose. Plasma E concentrations were measured by HPLC. A 2-compartment PK model was used to estimate total clearance of E. Results: Between 12/01 and 5/05, 55 patients were accrued but 1 never started therapy: male/female, 34/20; white/black, 46/8; median age 56 (range, 39–78); PS 0/1/2, 12/25/17. The distribution of treated/evaluable patients was: 6/5 in C1, 30/16 (attrition due to progressive disease) in C2, and 18/18 in C3. DLT consisted of both total and direct bilirubin ≥ 1.5 × baseline in 3 patients: C1, 1 of 5 at 50 mg; C2, 2 of 6 at 100 mg. In C2, 1 of 7 patients had grade 4 diarrhea/dehydration and grade 3 hypotension at 75 mg. No DLT was encountered in C3 with 12 patients at 150 mg. Clearance (mean ± SD) was cohort-dependent: 1.51 ± 0.64 (C1), 2.36 ± 1.17 (C2), 4.34 ± 2.53 (C3) l/hr; 2-sided exact Kruskal-Wallis p < 0.0006. Conclusions: Patients with RD tolerate 150 mg and appear to have normal clearance of E. Patients with HD should be treated at a reduced dose (i.e. 75 mg) consistent with their reduced clearance.

[Table: see text]

Ex vivo zidovudine (AZT) treatment of CD34+ bone marrow progenitors causes decreased steady state mitochondrial DNA (mtDNA) and increased lactate production

Haematopoietic suppression is one of the dose-limiting side effects of chronic zidovudine (AZT) therapy. We tested the hypothesis that AZT would reduce mitochondrial DNA (mtDNA) content in haematopoietic progenitors causing impaired haematopoiesis and mitochondrial dysfunction. We studied the effects of AZT 0-50 microM in vitro, on normal human CD34+ haematopoietic progenitor cells cultured ex vivo for up to 12 days. The mean AZT IC50 for granulocyte (phenotype CD15+/CD14-) and erythroid (phenotype glycophorin+/CD45-) cell proliferation was 2.5 microM (SD+/-0.7) and 0.023 microM (SD+/-0.005), respectively. In myeloid-rich cell cultures, the mean lactate content of the media, compared to untreated controls, increased by 86% (SD+/-23) at 10 microM AZT and in erythroid-rich cultures it increased by 134% (SD+/-24) in the presence of 0.5 microM AZT. In myeloid-rich cultures the AZT IC50 for the reduction in the mitochondrial/nuclear DNA content ratio was 5.6 microM, whereas in erythroid rich cultures this AZT IC50 was < 0.0005 microM. AZT produced concentration-dependent inhibition of CD34+ progenitor proliferation into both myeloid and erythroid lineages; erythropoiesis was more sensitive than myelopoiesis. Concurrently, AZT reduced steady state mtDNA content, while increasing lactate production. These findings support the hypothesis that mtDNA is one of the intracellular targets involved in the pathogenesis of AZT-associated bone marrow progenitor cell toxicity.

Taxanes synergize with the bispecific antibody MDXH447 to enhance antibody-dependent cell-mediated cytotoxicity

The interaction between antibody based therapy and cytotoxic chemotherapy is complex. To explore these interactions we investigated, in vitro, the effects of IC20 growth inhibitory concentrations of taxanes on bispecific antibody-mediated tumor cell cytotoxicity. MDXH447 is a bispecific antibody with specificity for the high affinity IgG receptor (CD64) and the type I epidermal growth factor receptor type (EGF-R). A431 cells, an epidermoid carcinoma cell line that over expresses EGF-R, were exposed to a range of IC20 growth inhibitory concentrations of paclitaxel or docetaxel. Interferon gamma activated monocytes were armed with MDXH447 and a standard chromium release antibody-dependent cell-mediated cytotoxicity (ADCC) assay was performed. Using the Chou and Talalay median effect analysis, we found that MDXH447-mediated ADCC was enhanced when A431 target cells were pretreated with paclitaxel or docetaxel. Median effect analysis of these interactions supported a synergistic interaction (CI < 1). Pretreatment of A431 cells with taxanes did not increase EGF-R expression compared to untreated controls. A431 epidermoid carcinoma cells pretreated with IC20 growth inhibitory concentrations of taxanes enhanced interferon gamma activated monocyte mediated ADCC killing through MDXH447.

Phase I study of twice-weekly gemcitabine and concomitant external-beam radiotherapy in patients with adenocarcinoma of the pancreas

PURPOSE

To determine the maximum tolerated dose and dose-limiting toxicity associated with twice-weekly gemcitabine and concomitant external-beam radiotherapy in patients with adenocarcinoma of the pancreas.

METHODS AND MATERIALS

Twenty-one patients with biopsy-proven adenocarcinoma of the pancreas were treated with external-beam radiotherapy to a dose of 50.4 Gy in 28 fractions, concurrent with gemcitabine, infused over 30 min before irradiation on a Monday and Thursday schedule. The dose of gemcitabine was escalated in 5 cohorts of 3--6 patients each. Initial gemcitabine dose was 10 mg/m(2), with dose escalation until dose-limiting toxicity was observed.

RESULTS

The maximum tolerated dose of gemcitabine was 50 mg/m(2), when given in a twice-weekly schedule with radiation. Dose-limiting toxicity was seen in 2 patients at 60 mg/m(2), and consisted of severe upper gastrointestinal bleeding approximately 1 month after completion of treatment. Six patients had radiographic evidence of response to treatment, and 5 of these underwent complete surgical resection. Three patients who underwent complete resection had been deemed to have unresectable tumors before enrollment on trial. Four patients are alive, including 2 without evidence of disease more than 1 year after resection.

CONCLUSION

The combination of external-beam radiation and twice-weekly gemcitabine at a dose of 50 mg/m(2) is well tolerated and shows promising activity for the treatment of pancreatic cancer. Our data suggest a higher maximum tolerated dose and different dose-limiting toxicity than previously reported. Further investigation of this regimen is warranted.

Asymptomatic QTc prolongation associated with quetiapine fumarate overdose in a patient being treated with risperidone

We report a patient who ingested a 2000-mg overdose of quetiapine fumarate (Seroquel). Her maintenance medications also included risperidone, venlafaxine, topiramate, and clonazepam. On presentation, she was drowsy, but had no other significant CNS signs and no cardiac symptoms or abnormal physical signs. Approximately 2 h after the quetiapine ingestion, an electrocardiogram (ECG) showed normal sinus rhythm at 95 beats/min with a corrected QT (QTc) interval of 537 ms (upper limit of normal = 440 ms). Plasma quetiapine concentration at that time was 1800 ng/ml. Continuous ECG monitoring for the subsequent 18 h did not reveal any episode of ventricular tachycardia. A 12-lead ECG 18 h post-overdose was normal with a QTc interval of 401 ms and the corresponding plasma quetiapine concentration was 160 ng/ml. She made an uneventful medical recovery from the toxic ingestion. This case suggests that when patients overdose on quetiapine while taking therapeutic doses of risperidone, such overdoses, even if not massive, can cause considerable QTc interval prolongation. We recommend that quetiapine overdose patients undergo continuous ECG monitoring for 12-18 h post-ingestion.

Pharmacokinetic-pharmacodynamic relationships of the bispecific antibody MDX-H210 when administered in combination with interferon gamma: a multiple-dose phase-I study in patients with advanced cancer which overexpresses HER-2/neu

INTRODUCTION

MDX-H210 is a Fab'xFab' bispecific antibody (BsAb) constructed chemically by crosslinking Fab' mAb 520C9 (anti-HER-2/neu) and Fab' mAbH22 (anti-CD64).

STUDY DESIGN AND OBJECTIVES

This was a dose escalation study of intravenous MDX-H210 (1-70 mg/m(2)), preceded 24 h beforehand by subcutaneous IFNgamma (50 microg/m(2) to up-regulate FcgammaRI) administered three times a week for 3 weeks. We investigated the pharmacokinetic-pharmacodynamic relationships between MDX-H210 C(max) and AUC and (i) MDX-H210 binding to peripheral blood monocytes and neutrophils, (ii) the peak plasma G-CSF, IL-6, IL-8 and TNFalpha concentrations, and (iii) the observed clinical toxicity.

RESULTS

23 patients (19F:4M; median age 51.5; range 25-72 y) with advanced HER-2/neu positive cancers (19 breast, three prostate and one lung) were studied. Plasma MDX-H210 concentrations over time, circulating numbers of monocytes and neutrophils, percent saturation of monocyte and neutrophil FcgammaRI, and plasma concentrations over time of G-CSF, IL-6, IL-8 and TNFalpha were measured and clinical toxicity monitored. The E(max) pharmacodynamic model best fitted the relationship of MDX-H210 C(max) and the maximum percent saturation of both monocytes (E(max)=74.6; EC(50)=0.9 microg/ml) and neutrophils (E(max)=66.2; EC(50)=2.3 microg/ml) on the first day of treatment. On the last day of treatment, day 19, these parameters were E(max)=57.0% and EC(50)=0.46 microg/ml for monocytes and E(max)=61.9% and EC(50)=0.26 microg/ml for neutrophils. No positive relationship was defined between the log MDX-H210 C(max) and the log peak plasma IL-6, G-CSF, TNF or IL-8 concentrations on day 1. On day 19 these plasma cytokine concentrations were undetectable post MDX-H210 therapy. There was no consistent relationship between MDX-H210 C(max) and the observed clinical toxicities.

CONCLUSIONS

These data suggest that MDX-H210 C(max) and AUC could be related by the E(max) model to maximum percent FcgammaRI saturation on circulating monocytes and neutrophils in the patients studied. After day 1, the post MDX-H210 therapy cytokine response attenuated over time, consistent with desensitization. We did not find a relationship between log MDX-H210 C(max) and peak plasma cytokine concentrations or clinical toxicities.

Bispecific antibody-targeted phagocytosis of HER-2/neu expressing tumor cells by myeloid cells activated in vivo

Studies from our laboratory and others have established that both mononuclear phagocytes and neutrophils mediate very efficient cytotoxicity when targeted through Fc receptors using a suitable monoclonal or bispecific antibody (BsAb). Cross-linking an Fc receptor for IgG (FcgammaR) triggers multiple anti-tumor activities including superoxide generation, cytokine and enzyme release, phagocytosis and antibody-dependent cellular cytotoxicity (ADCC). In this report, using unfractionated leukocytes and two color flow cytometric analysis, we describe the phagocytic capacity of peripheral blood polymorphonuclear cells (PMN) and monocytes isolated from patients enrolled in a phase I clinical trial of MDX-H210 given in combination with IFNgamma. MDX-H210 is a BsAb targeting the myeloid trigger molecule FcgammaRI and the HER-2/neu proto-oncogene product overexpressed on a variety of adenocarcinomas. In this trial, cohorts of patients received escalating doses of MDX-H210 3 times per week for 3 weeks. Interferon-gamma (IFNgamma) was given 24 h prior to each BsAb infusion. Our results demonstrate that monocytes from these patients were inherently capable of phagocytosing the HER-2/neu positive SK-BR-3 cell line and that addition of MDX-H210 into the assay significantly enhanced the number of targets phagocytosed. Two days after administration of an immunologically active dose of MDX-H210 (10 mg/m2), monocytes from these patients were able to phagocytose greater amounts of target cell material, indicating that these cells remained armed with functionally sufficient BsAb for at least 48 h. PMN from these patients very efficiently mediated phagocytosis through FcgammaRI after being treated with IFNgamma, but not before. We conclude that phagocytosis is not only an efficient mechanism of myeloid cell-mediated cytotoxicity, but may also be a mechanism by which antigens from phagocytosed cells can enter a professional antigen presenting cell for processing and presentation.

Phase I pilot trial of the bispecific antibody MDXH210 (anti-Fc gamma RI X anti-HER-2/neu) in patients whose prostate cancer overexpresses HER-2/neu

The goal of this study was to evaluate, in patients with prostate cancer, the toxicity profile and biologic activity of the bispecific antibody MDXH210, which has specificity for the non-ligand-binding site of the high-affinity immunoglobulin G receptor (Fc gamma RI) and the extracellular domain of the HER-2/neu proto-oncogene product. Patients with prostate cancer that expressed HER-2/neu were entered into a phase I dose-escalation trial of MDXH210. Patients received an intravenous infusion MDXH210 during a period of 2 h three times per week for 2 weeks and were monitored for toxicity. Pharmacokinetic and pharmacodynamic parameters were measured and included the biologic end points of monocyte-bound MDXH210, cytokine production, and clinical response. Seven patients were treated with MDXH210 doses ranging from 1 to 8 mg/m2. In general, MDXH210 was well tolerated, with only mild infusion-related malaise, fever, chills, and myalgias. No dose-limiting toxic effects were observed. Biologic effects included induction of low plasma concentrations of tumor necrosis factor-alpha and interleukin-6 observed immediately after MDXH210 infusion and 70% saturation of circulating monocyte-associated Fc gamma RI with MDXH210 at a dose level of 4 to 8 mg/m2. Five of six patients had stable prostate-specific antigen levels during the course of 40 days or more. Circulating plasma HER-2/neu levels decreased by 80% at days 12 and 29 (p = 0.03 and 0.06, respectively, by the Wilcoxon signed rank test). MDXH210 can be given safely to patients with HER-2/neu-positive prostate cancer in doses of at least 8 mg/m2. At the doses studied, biologic activity was demonstrated and characterized by binding of MDXH210 to circulating monocytes, release of monocyte-derived cytokines, a decrease in circulating HER-2/neu, and short-term stabilization of prostate-specific antigen levels.

Visualization of intravenously administered contrast material in the CSF on fluid-attenuated inversion-recovery MR images: an in vitro and animal-model investigation

BACKGROUND AND PURPOSE

The FLAIR (fluid-attenuated inversion-recovery) pulse sequence has been shown to be sensitive to abnormalities of the subarachnoid space. Our clinical experience led us to investigate whether intravenously injected contrast material can affect the appearance of the subarachnoid space on FLAIR MR images.

METHODS

After noting unexplained high signal in the subarachnoid space on FLAIR images in a patient, we studied two dogs with sequential FLAIR MR imaging after i.v. administration of contrast material. A third dog was studied with a 6-hour delayed FLAIR sequence after triple-dose (0.3 mmol/kg) i.v. contrast administration. CSF was obtained from two animals for measurement of gadolinium concentration. A phantom was developed to determine the lowest concentration at which the effects of gadolinium were evident on FLAIR images in vitro.

RESULTS

In all three animals, the appearance of the CSF in the ventricles or subarachnoid space was modified after administration of i.v. contrast. This was most evident on delayed images. The CSF samples showed a gadolinium concentration of 0.007 mmol/L in the dog who received the 0.1 mmol/kg dose and 0.02 mmol/L in the dog who received a triple dose. In our in vitro phantom experiments, gadolinium effects were evident on FLAIR images at a concentration four times lower than those on T1-weighted images.

CONCLUSION

I.v. contrast material can cross into the CSF in sufficient concentration to alter the appearance of the subarachnoid space on FLAIR images in normal dogs. Although we encountered two patients with CNS disease in whom enhancement of the CSF was seen on postcontrast FLAIR images, additional investigation is needed in humans to determine whether enhancement may occur at triple dose in healthy subjects.

Noradrenergic modulation of cognitive flexibility in problem solving

Stress causes impaired performance on tests of creativity. Drugs that block beta-adrenergic receptors improve test performance in patients with test anxiety. Furthermore, catecholamine precursors (L-DOPA) reduce the flexibility of semantic networks. Our study investigated the effect of noradrenergic system modulation on cognitive flexibility in problem solving. Eighteen normal subjects undertook three problem solving tasks (number series, shape manipulation and anagrams) 45 min after propranolol, placebo and ephedrine. On the task that appeared to rely most heavily on cognitive flexibility (anagrams), subjects who were most able to solve these problems demonstrated significantly shorter solution times (logarithmic scores) after propranolol than after ephedrine. This suggested that the noradrenergic system exerts a modulatory effect on cognitive flexibility in problem solving.

Escalating multiple-dose safety and tolerance study of oral WR 6026 in HIV-infected subjects: AIDS clinical trials group 173

WR 6026 is an 8-aminoquinoline with activity against Pneumocystis carinii in vitro and in an animal model of P. carinii pneumonia that has predicted the clinical utility of related compounds. This study was conducted to assess the safety and tolerance of WR 6026 given once daily for 21 days to HIV-infected subjects with CD4 counts <500 cells/microl. This double-blind, placebo-controlled study employed WR 6026 doses starting at 30 mg once daily and increasing to 60, 90, 120, or 150 mg once daily. Weekly visits for clinical and laboratory monitoring were conducted. Forty-nine study subjects, including 25 subjects with CD4 counts <200 cells/microl and 12 subjects with CD4 counts <100 cells/microl, entered the study. The maximum tolerated dose was 120 mg/day. Dose-limiting methemoglobinemia (>20%) was seen in 3 of 6 study subjects who received 150 mg/day for > or =19 days. Methemoglobin level was correlated with peak plasma WR 6026 concentrations. Three other study subjects developed skin rashes that may have been drug-related, and two developed asymptomatic serum triglyceride levels >1000 mg/dl. We conclude that WR 6026 is well tolerated at doses up to 120 mg/day for 21 days in HIV-infected volunteers including those with CD4 counts <200 cells/microl. Methemoglobinemia appears to be the primary dose-limiting toxicity.

Induction of cytochrome P4503A by taxol in primary cultures of human hepatocytes

In primary cultures of human hepatocytes, paclitaxel (Taxol), at pharmacological concentrations, was demonstrated to induce immunoreactive cytochrome P4503A (CYP3A). The magnitude of the inductive response of the hepatocytes to Taxol varied in five separate cultures. In general, exposure to increasing concentrations of Taxol (0.2 to 10 microM) resulted in increases in immunoreactive CYP3A. In four of the cultures, treatment of hepatocytes with the lowest concentration of Taxol tested (0.2 microM) resulted in approximately two-fold increases in CYP3A. In the other culture, however, a six-fold increase in CYP3A was observed at 0.2 microM. Taxol was almost as effective as rifampicin in inducing CYP3A in two of the cultures, but less effective than rifampicin in two other cultures. CYP3A4 mRNA was increased by Taxol. Increases in CYP3A4 mRNA correlated with increases in the levels of immunoreactive CYP3A. These results demonstrate that Taxol is a potent inducer of CYP3A in human hepatocytes. The clinical significance of these findings is discussed.

The role of polymorphonuclear neutrophils (PMNs) in clearance of granulocyte colony-stimulating factor (G-CSF) in vivo and in vitro

Previous studies have suggested that in vivo granulocyte colony-stimulating factor (G-CSF) pharmacokinetics may change over time. We studied three patients treated with high-dose chemotherapy followed by autologous bone marrow transplantation (ABMT) for metastatic breast cancer after intravenous administration of recombinant human (rh) G-CSF (5 or 16 microg/kg/day). We investigated plasma G-CSF concentrations and absolute neutrophil counts (ANCs/pL) in these patients on three separate days. G-CSF plasma clearance increased with time post-ABMT with no change in the apparent volume of distribution (Vd) of G-CSF. Regression analysis of G-CSF plasma clearance and ANCs revealed a linear relationship, with r2 = 0.85 (p = 0.00025). We further investigated this phenomenon in vitro by estimating pharmacokinetic parameters for rhG-CSF using a model in which polymorphonuclear neutrophils (PMNs) were incubated with rhG-CSF. We found that, at low G-CSF concentrations in vitro, there was an increase in G-CSF clearance with increasing ANCs, but at higher G-CSF concentrations this relationship did not hold. We suggest that this finding resulted from aggregation and polymerization of G-CSF at high concentrations when kept at 37 degrees C for 24-48 hours in vitro. Using fluorescence staining techniques, our data suggest there are changes over time in the amount of G-CSF bound to PMNs. These changes may reflect reexpression or recycling of the G-CSF receptor, and could explain the continuing clearance of G-CSF by PMNs in vitro. The strong positive correlation between G-CSF plasma clearance and ANCs in vivo is compatible with the hypothesis that neutrophils mediate one of the major pathways for rhG-CSF clearance.

Olsalazine and 6-mercaptopurine-related bone marrow suppression: a possible drug-drug interaction

A patient with refractory Crohn's disease had two separate episodes of bone marrow suppression while receiving 50 to 75 mg 6-mercaptopurine a day and 1000 to 1750 mg olsalazine a day. This adverse reaction necessitated dose reduction of 6-mercaptopurine on the first occasion and withdrawal of 6-mercaptopurine and olsalazine on the second occasion. The patient's red blood cell thiopurine methyltransferase (TPMT) activity was 1.2 U per milliliter red blood cells (low normal range) and her TPMT genotype was wild-type sequence for all known alleles of TPMT that result in low TPMT enzyme activity. In vitro enzyme kinetic studies confirmed the hypothesis that olsalazine and olsalazine-O-sulfate are potent noncompetitive inhibitors of recombinant human TPMT. We suggest that the patient's relatively low baseline level of TPMT activity was inhibited by olsalazine and olsalazine-O-sulfate, leading to decreased clearance of 6-mercaptopurine and its accumulation. This ultimately increased intracellular 6-thiopurine nucleotide levels to toxic concentrations, which caused bone marrow suppression.

Delayed sequelae after acute overdoses or poisonings: cranial neuropathy related to ethylene glycol ingestion

A 31-year-old woman came to the hospital with breathlessness, confusion, and a refractory anion gap metabolic acidosis; acute renal failure subsequently developed. Her blood ethylene glycol concentration was 390 mg/L, and she was treated with an intravenous ethanol infusion and hemodialysis. During the tenth and eleventh day after admission bilateral seventh cranial nerve paralysis developed, as well as bilateral dysfunction of cranial nerves II, V, VIII, IX, X and XII. Magnetic resonance imaging of her head showed gadolinium enhancement of the fifth cranial nerve bilaterally and a communicating hydrocephalus. Over the subsequent 11 months she recovered full function of her cranial nerves V, VII, IX, X, and XII, and she had subjective clinical improvement to baseline function in cranial nerves II and VIII. This case serves to introduce a discussion of agents that cause delayed complications after their acute toxic ingestion.

A study of the effects of sumatriptan on myocardial perfusion in healthy female migraineurs using 13NH3 positron emission tomography

Sumatriptan, a 5-HT1D receptor agonist, is believed to alleviate migraine attacks by extracerebral vasoconstriction. Chest pain associated with myocardial ischemia may occur after sumatriptan administration. We investigated the effect of a single 6-mg subcutaneous dose of sumatriptan on myocardial perfusion (MP) as measured by 13NH3 positron emission tomography (PET) in a randomized, double-blind, placebo-controlled, crossover trial at the Clinical PET Centre, Guy's and St. Thomas' Hospitals, London. Nineteen volunteer female migraineurs, age range 33 to 62 years, at low risk for ischemic heart disease were included. All bad undergone previous treatment with oral or intravenous sumatriptan. Patients were recruited by advertisement and referral from local neurology specialists. Each volunteer underwent two scanning sessions. On each occasion, a baseline dynamic 13NH3 PET scan was acquired followed by a 13NH3 PET scan 10 minutes after subcutaneous injection of placebo or 6 mg of sumatriptan. Regional MP was measured in five myocardial regions using the Patlak system of image analysis. The mean % change from baseline (+/-SD) in global MP after placebo was +9.5% +/- 18.0 and after sumatriptan was +6.6% +/- 18.8 (repeated measures ANOVA for treatment effect p = 0.56). There were no significant differences in MP changes from baseline observed in any of the five myocardial regions (treatment p = 0.32 to 0.84). These data suggest that in healthy female migraineurs, a single 6-mg subcutaneous dose of sumatriptan does not cause a significant change in regional or global myocardial perfusion.

Effect of Taxol on cytochrome P450 3A and acetaminophen toxicity in cultured rat hepatocytes: comparison to dexamethasone

The purpose of this study was to determine if Taxol induced CYP3A in primary cultures of rat hepatocytes and, if so, whether induction of CYP3A would increase acetaminophen toxicity. Taxol caused a concentration-dependent increase in the amount of immunoreactive CYP3A and in the steady-state levels of CYP3A1/DEX but not CYP3A2 mRNA. Similar concentration-dependent increases in toxicity as measured by a decrease in protein synthesis were observed after exposure of cells to acetaminophen for 7 hr whether cells were pretreated with Taxol or dexamethasone. Increased release of lactate dehydrogenase occured after 24 hr exposure to acetaminophen, with no further decreases in protein synthesis than those observed at 7 hr. Increases in acetaminophen toxicity correlated with increased covalent binding of acetaminophen to cellular proteins. Triacetyloleandomycin, a selective inhibitor of CYP3A, completely protected the cells against acetaminophen toxicity in both Taxol- and dexamethasone-pretreated cells and prevented the increase in covalent binding of acetaminophen to cellular proteins. These results demonstrate that Taxol, like dexamethasone, induces CYP3A and that increases in this P450 are responsible for increased acetaminophen toxicity.

A study of 5 day fractionated ifosfamide pharmacokinetics in consecutive treatment cycles

1. Ifosfamide demonstrates increased clearance with time when administered daily for 5 days. The objectives of this study were to define whether the increased ifosfamide clearance was sustained between treatment cycles and whether it was reproducible in consecutive treatment cycles. 2. Seven patients with inoperable cancer received 1.5 g m-2 ifosfamide infused intravenously over 0.5 h, each day for 5 days, for two consecutive cycles. Urine and appropriately timed blood samples were collected for up to 24 h post ifosfamide infusion on day 1 and day 5. Plasma ifosfamide concentrations were assayed by gas liquid chromatography and pharmacokinetic parameters were imputed using non-compartmental analysis. 3. The difference in the mean (n = 7) total ifosfamide plasma clearance between day 5 and day 1 of Cycle I was an increase of 56.8 ml min-1 (99.8% CIs + 22.6-->+ 91.4). The difference in the mean (n = 7) total ifosfamide plasma clearance between day 1 of Cycle II and day 5 was a decrease of 61.9 ml min-1 (99.8% CIs -111.2 -->-12.6). The magnitude of the mean increase in total ifosfamide plasma clearance in Cycle II and Cycle I was similar because the difference between these means (0.9 ml min-1, 99.8% CIs -63.7-->+65.3) was not statistically significant. There was no change in the apparent volume of distribution of ifosfamide between the two study days in either of Cycle I or II, or between cycles. 4. The difference in the mean (n = 7) ifosfamide renal clearance between day 5 and day 1 of Cycle I was minus 0.4 ml min-1 (99.8% CIs -8.5-->+8.6); the means +/- s.d. wee 6.3 +/- 2.6 ml min-1 and 6.7 +/- 3.2 ml min-1 respectively. The difference in the mean (n = 4) ifosfamide renal clearance between day 5 and day 1 of Cycle II was -0.2 ml min-1 (99.8% CIs -5.7-->+5.2); the means +/- s.d. were 7.8 +/- 6.1 ml min-1 and 8.0 +/- 6.2 ml min-1 respectively. 5. These data suggest that the increase in total ifosfamide plasma clearance with time in a 5 day fractionated regimen was due to an increase in ifosfamide metabolism which was not sustained over the 21 days between cycles, but was reproducible and of a similar magnitude in the two consecutive treatment cycles studied.

Clinical trials of bispecific antibody MDX-210 in women with advanced breast or ovarian cancer that overexpresses HER-2/neu

MDX-210 is a bispecific antibody (BsAb) that recognizes Fc gamma R1 on monocytes and macrophages and the cell surface product of the HER-2/neu oncogene, which is overexpressed on some breast and ovarian cancers. Clinical trials have demonstrated that treatment with MDX-210 is well tolerated and that MDX-210 is both immunologically and clinically active. Optimization of the dose and schedule of MDX-210 and development of combination treatments with cytokines that modulate immune effector cells will greatly enhance the efficacy of this novel BsAb construct for treatment of tumours that overexpress HER-2/neu. We envision that MDX-210 will be effective for treating patients with tumors that overexpress HER-2/neu, especially in the minimal disease setting.

Phase Ia/Ib trial of bispecific antibody MDX-210 in patients with advanced breast or ovarian cancer that overexpresses the proto-oncogene HER-2/neu

PURPOSE

MDX-210 is a bispecific antibody that binds simultaneously to type I Fc receptors for immunoglobulin G (IgG) (Fc gamma RI) and to the HER-2/neu oncogene protein product. MDX-210 effectively directs Fc gamma RI-positive effector cells such as monocytes and macrophages to phagocytose or kill tumor cells that overexpress HER-2/neu. The goals of this phase Ia/Ib trial were to determine the maximum-tolerated dose (MTD) and/or the optimal biologic dose (OBD) of MDX-210.

PATIENTS AND METHODS

Patients with advanced breast or ovarian cancer that overexpressed HER-2/neu were eligible for treatment. Cohorts of three patients received a single intravenous (IV) infusion of MDX-210 at increasing dose levels from 0.35 to 10.0 mg/m2.

RESULTS

Treatment was well tolerated, with most patients experiencing transient grade 1 to 2 fevers, malaise, and hypotension only. Two patients experienced transient grade 3 hypotension at 10.0 mg/m2. Transient monocytopenia and lymphopenia developed at 1 to 2 hours, but no other hematologic changes were observed. Doses of MDX-210 > or = 3.5 mg/m2 saturated > or = 80% of monocyte Fc gamma RI and produced peak plasma concentrations > or = 1 microgram/mL, which is greater than the concentration for optimal monocyte/macrophage activation in vitro. Elevated plasma levels of the monocyte products tumor necrosis factor alpha (TNF alpha), interleukin-6 (IL-6), granulocyte colony-stimulating factor (G-CSF), and neopterin were observed with maximal levels at doses > or = 7.0 mg/m2. Localization of MDX-210 in tumor tissue was demonstrated in two patients. One partial and one mixed tumor response were observed among 10 assessable patients.

CONCLUSION

MDX-210 is immunologically active at well-tolerated doses. The MTD and OBD is 7 to 10 mg/m2.