TY - JOUR A1 - Minckwitz, Gunter von A1 - Harder, Sebastian A1 - Hövelmann, Sascha A1 - Jäger, Elke A1 - Batran, Salah-Eddin al- A1 - Loibl, Sibylle A1 - Atmaca, Akin A1 - Cimpoiasu, Christian A1 - Neumann, Antje A1 - Abera, Aklil A1 - Knuth, Alexander A1 - Kaufmann, Manfred A1 - Jäger, Dirk A1 - Maurer, Alexander B. A1 - Wels, Winfried T1 - Phase I clinical study of the recombinant antibody toxin scFv(FRP5)-ETA specific for the ErbB2/HER2 receptor in patients with advanced solid malignomas T2 - Breast cancer research N2 - Introduction: ScFv(FRP5)-ETA is a recombinant antibody toxin with binding specificity for ErbB2 (HER2). It consists of an N-terminal single-chain antibody fragment (scFv), genetically linked to truncated Pseudomonas exotoxin A (ETA). Potent antitumoral activity of scFv(FRP5)-ETA against ErbB2-overexpressing tumor cells was previously demonstrated in vitro and in animal models. Here we report the first systemic application of scFv(FRP5)-ETA in human cancer patients. Methods: We have performed a phase I dose-finding study, with the objective to assess the maximum tolerated dose and the dose-limiting toxicity of intravenously injected scFv(FRP5)-ETA. Eighteen patients suffering from ErbB2-expressing metastatic breast cancers, prostate cancers, head and neck cancer, non small cell lung cancer, or transitional cell carcinoma were treated. Dose levels of 2, 4, 10, 12.5, and 20 μg/kg scFv(FRP5)-ETA were administered as five daily infusions each for two consecutive weeks. Results: No hematologic, renal, and/or cardiovascular toxicities were noted in any of the patients treated. However, transient elevation of liver enzymes was observed, and considered dose limiting, in one of six patients at the maximum tolerated dose of 12.5 μg/kg, and in two of three patients at 20 μg/kg. Fifteen minutes after injection, peak concentrations of more than 100 ng/ml scFv(FRP5)-ETA were obtained at a dose of 10 μg/kg, indicating that predicted therapeutic levels of the recombinant protein can be applied without inducing toxic side effects. Induction of antibodies against scFv(FRP5)-ETA was observed 8 days after initiation of therapy in 13 patients investigated, but only in five of these patients could neutralizing activity be detected. Two patients showed stable disease and in three patients clinical signs of activity in terms of signs and symptoms were observed (all treated at doses ≥ 10 μg/kg). Disease progression occurred in 11 of the patients. Conclusion: Our results demonstrate that systemic therapy with scFv(FRP5)-ETA can be safely administered up to a maximum tolerated dose of 12.5 μg/kg in patients with ErbB2-expressing tumors, justifying further clinical development. Y1 - 2005 UR - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/4330 UR - https://nbn-resolving.org/urn:nbn:de:hebis:30-11563 SN - 1465-542X SN - 1465-5411 N1 - © 2005 von Minckwitz et al, licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/ 2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is cited: http://breast-cancer-research.com/content/7/5/R617 s.a. Correction http://publikationen.ub.uni-frankfurt.de/volltexte/2007/4452/ VL - 7 IS - 5 SP - R617 EP - R626 PB - BioMed Central CY - London ER -