Preclinical pharmacokinetics, pharmacodynamics, and activity of a humanized anti-CD40 antibody (SGN-40) in rodents and non-human primates.

1. Cell-surface expression of CD40 in B-cell malignancies and multiple solid tumors has raised interest in its potential use as a target for antibody-based cancer therapy. SGN-40, a humanized monoclonal anti-CD40 antibody, mediates antibody-dependent cytotoxicity and inhibits B-cell tumor growth in vitro, properties of interest for the treatment of cancers, and is currently in Phase I clinical trials for B-cell malignancies. In this study, we determined in vivo activity and pharmacokinetics properties of SGN-40. 2. Effect of SGN-40 in xenograft model of CD40-expressing B-cell lymphoma in severe-combined immune deficiency mice and its in vivo pharmacokinetics properties in normal mice, rats and cynomolgus monkeys were studied. 3. Treatment with SGN-40 significantly increased the survival of mice xenografted with human B-cell lymphoma cell line. SGN-40 exhibited nearly 100% bioavailability in mice and it cleared faster when given at a low dose. In monkeys, clearance of SGN-40 was also much faster at low dose, suggesting nonlinear pharmacokinetics in these species. In rats, however, SGN-40 clearance at all tested doses was similar, suggesting that pharmacokinetics were linear in this dose range in rats. Administration of SGN-40 to monkeys also produced marked, dose-dependent, and persistent depletion of peripheral CD20(+) B lymphocytes. 4. Data presented in this report suggest that SGN-40 is active in in vivo, and based upon interspecies scaling, SGN-40 clearance in humans is predicted to be similar to observed SGN-40 clearance in monkeys. These data suggest that SGN-40 has appropriate pharmacokinetic properties that support its clinical use.

Phase 1 study of erlotinib HCl alone and combined with temozolomide in patients with stable or recurrent malignant glioma.

The purpose of this study was to define the maximum tolerated dose of erlotinib and characterize its pharmaco-kinetics and safety profile, alone and with temozolomide, with and without enzyme-inducing antiepileptic drugs (EIAEDs), in patients with malignant gliomas. Patients with stable or progressive malignant primary glioma received erlotinib alone or combined with temozolomide in this dose-escalation study. In each treatment group, patients were stratified by coadministration of EIAEDs. Erlotinib was started at 100 mg orally once daily as a 28-day treatment cycle, with dose escalation by 50 mg/day up to 500 mg/day. Temozolomide was administered at 150 mg/m2 for five consecutive days every 28 days, with dose escalation up to 200 mg/m2 at the second cycle. Eightythree patients were evaluated. Rash, fatigue, and diarrhea were the most common adverse events and were generally mild to moderate. The recommended phase 2 dose of erlotinib is 200 mg/day for patients with glioblastoma multiforme who are not receiving an EIAED, 450 mg/day for those receiving temozolomide plus erlotinib with an EIAED, and at least 500 mg/day for those receiving erlotinib alone with an EIAED. Of the 57 patients evaluable for response, eight had a partial response (PR). Six of the 57 patients had a progression-free survival of longer than six months, including four patients with a PR. Coadministration of EIAEDs reduced exposure to erlotinib as compared with administration of erlotinib alone (33%-71% reduction). There was a modest pharmacokinetic interaction between erlotinib and temozolomide. The favorable tolerability profile and evidence of antitumor activity indicate that further investigation of erlotinib is warranted.

Phase I/II trial evaluating the anti-vascular endothelial growth factor monoclonal antibody bevacizumab in combination with the HER-1/epidermal growth factor receptor tyrosine kinase inhibitor erlotinib for patients with recurrent non-small-cell lung cancer.

PURPOSE: Bevacizumab (Avastin; Genentech, South San Francisco, CA) is a recombinant, humanized anti-vascular endothelial growth factor monoclonal antibody. Erlotinib HCl (Tarceva, OSI-774; OSI Pharmaceuticals, New York, NY) is a potent, reversible, highly selective and orally available HER-1/epidermal growth factor receptor tyrosine kinase inhibitor. Preclinical data in various xenograft models produced greater growth inhibition than with either agent alone. Additionally, both agents have demonstrated benefit in patients with previously treated non-small-cell lung cancer (NSCLC). PATIENTS AND METHODS: A phase I/II study in two centers examined erlotinib and bevacizumab (A+T) in patients with nonsquamous stage IIIB/IV NSCLC with > or = one prior chemotherapy. In phase I, erlotinib 150 mg/day orally plus bevacizumab 15 mg/kg intravenously every 21 days was established as the phase II dose, although no dose-limiting toxicities were observed. Phase II assessed the efficacy and tolerability of A+T at this dose. Pharmacokinetic parameters were evaluated. ResultsForty patients were enrolled and treated in this study (34 patients at phase II dose); the median age was 59 years (range, 36 to 72 years), 21 were female, 30 had adenocarcinoma histology, nine were never-smokers, and 22 had > or = two prior regimens (three patients had > or = four prior regimens). The most common adverse events were mild to moderate rash, diarrhea, and proteinuria. Preliminary data showed no pharmacokinetic interaction between A + T. Eight patients (20.0%; 95% CI, 7.6% to 32.4%) had partial responses and 26 (65.0%; 95% CI, 50.2% to 79.8%) had stable disease as their best response. The median overall survival for the 34 patients treated at the phase II dose was 12.6 months, with progression-free survival of 6.2 months. CONCLUSION: Encouraging antitumor activity and safety of A + T support further development of this combination for patients with advanced NSCLC and other solid tumors.

Phase I trial of irinotecan, infusional 5-fluorouracil, and leucovorin (FOLFIRI) with erlotinib (OSI-774): early termination due to increased toxicities.

PURPOSE: This phase I study was conducted to establish the dose-limiting toxicities and maximum-tolerated dose of erlotinib, an oral epidermal growth factor receptor tyrosine kinase inhibitor, in combination with FOLFIRI, a standard regimen of irinotecan, leucovorin, and infusional 5-fluorouracil (5-FU) in patients with advanced colorectal cancer. EXPERIMENTAL DESIGN: The trial used a dose-escalation design beginning with 100 mg/day erlotinib continuously and dose-reduced FOLFIRI (150 mg/m2 i.v. day 1 irinotecan, 200 mg/m2 i.v. leucovorin, 320 mg/m2 i.v. bolus days 1 to 2 5-FU, and 480 mg/m2 i.v. 5-FU infusion over 22 hours, days 1 to 2) administered in 6-week cycles (three FOLFIRI treatments). Plasma sampling was performed for irinotecan, erlotinib, and 5-FU for pharmacokinetic analysis during cycle 1. RESULTS: The study was halted after six patients at the lowest dose level due to unexpectedly severe toxicities, including disfiguring grade 2 rash (three patients), grade 3 diarrhea (three patients), and grade > or = 3 neutropenia (three patients). All patients required some dose interruption or reduction of either erlotinib or FOLFIRI, and only one patient completed two 6-week cycles of therapy. Five patients had stable disease after one cycle, and one patient had a partial response. No plasma pharmacokinetic interaction was observed that could explain the observed increased toxicity. CONCLUSIONS: FOLFIRI combined with erlotinib causes excessive toxicity at reduced doses. These findings contrast with available data regarding the optimal safety profile of trials combining small molecule epidermal growth factor receptor inhibitors with other conventional chemotherapy and highlight the need to perform safety-oriented studies of such combinations.

Tissue distribution, stability, and pharmacokinetics of Apo2 ligand/tumor necrosis factor-related apoptosis-inducing ligand in human colon carcinoma COLO205 tumor-bearing nude mice.

Apo2L/TRAIL [Apo2 ligand/tumor necrosis factor (TNF)-related apoptosis-inducing ligand], a member of the TNF cytokine superfamily, induces cell death by apoptosis in a number of human cancer cells and is a potential agent for cancer therapy. We have characterized the in vitro stability of Apo2L/TRAIL in human serum and the tissue distribution and metabolism of Apo2L/TRAIL in a xenograft model of human colon carcinoma (COLO205). Apo2L/TRAIL was stable after incubation in human serum, with no significant high molecular weight complexes or degradation products observed. After i.v. administration of 125I-Apo2L/TRAIL to mice, a small percentage of the radiolabeled drug was seen as high molecular weight complex or as low molecular weight degradation products in plasma. However, the most abundant radioactive species corresponded to the intact Apo2L/TRAIL monomer, indicative of the relative stability of this recombinant protein in blood. Distribution of 125I-Apo2L/TRAIL to organs and solid xenograft tumors was limited. Intact 125I-Apo2L/TRAIL was detectable in the solid tumor at all time points and was the only tissue in which radioactivity transiently increased over time. Kidney contained the highest levels of radioactivity. Radioactive signal reached a tissue-to-blood ratio of 18 in the kidney cortex region when 125I-Apo2L/TRAIL was given in the presence of excess unlabeled ligand. In contrast to blood, extensive 125I-Apo2L/TRAIL degradation was observed in the kidney and, to a lesser degree, in the solid tumor and other organs, including liver, spleen, and lung. Our studies demonstrated that Apo2L/TRAIL is stable in the circulation, localizes to human solid xenograft tumors, and is primarily eliminated through the kidney.

Targeting death receptors in cancer with Apo2L/TRAIL.

Unlike conventional cancer therapeutics, death receptor ligands trigger tumor cell apoptosis independently of the p53 tumor suppressor gene, which frequently is inactivated in cancer. The death receptor ligand Apo2 ligand/tumor necrosis factor-related apoptosis-inducing ligand (Apo2L/TRAIL) offers promising therapeutic potential based on its ability to induce apoptosis in various cancer cell lines with little toxicity toward normal cells. Moreover, Apo2L/TRAIL displays single-agent activity and cooperates with chemotherapy or radiotherapy in a variety of tumor xenograft mouse models. Thus, Apo2L/TRAIL might be effective against tumors that have acquired resistance to conventional therapy, and could augment the efficacy of current treatment in a wide spectrum of cancers.