Targeted tumor therapy with a fusion protein of an antiangiogenic human recombinant scFv and yeast cytosine deaminase.

In adults, endothelial cell division occurs only in wound healing, during menstruation, or in diseases such as wet age-related macular degeneration or development of benign or malignant tissues. Angiogenesis is one of the major requirements to supply the fast developing tumor tissue with oxygen and nutrients, and enables it to spread into other tissues far from its origin. We selected the extradomain B (ED-B), a splice variant of fibronectin, which is exclusively expressed in ovaries, uterus, during wound healing, and in tumor tissues, as a target for the development of an innovative antiangiogenic, prodrug-based targeted tumor therapy approach. We designed a fusion protein termed L19CDy-His, consisting of the antibody single chain fragment L19 for targeting ED-B and yeast cytosine deaminase for the conversion of 5-fluorocytosine into cytotoxic 5-fluorouracil. We purified high amounts of the fusion protein from Pichia pastoris that is stable, enzymatically active, and retains 75% of its activity after incubation with human plasma for up to 72 hours. The binding of L19CDy-His to ED-B was confirmed by an enzyme-linked immunosorbent assay and quantified by surface plasmon resonance spectroscopy determining a KD value of 81±7 nM. L19CDy-His successfully decreased cell survival of the murine ED-B-expressing teratocarcinoma cell line F9 upon addition of the prodrug 5-fluorocytosine. Our data demonstrate the suitability of targeting ED-B by L19CDy-His for effective prodrug-based tumor therapy.

Ifosfamide/liposomal daunorubicin is a well tolerated and active first-line chemotherapy regimen in advanced soft tissue sarcoma: results of a phase II study.

BACKGROUND: The anthracycline/ifosfamide combination is the most effective chemotherapy in soft tissue sarcoma. To improve the tolerability and potential efficacy of this combination, the authors combined a moderate dose of continuous infusion ifosfamide with liposomal daunorubicin (L-Dauno). METHODS: In a single-arm, Phase II study, 40 patients with a median age of 57 years (range, 19-78 years) were enrolled. Of these, 35 patients were treated with first-line chemotherapy. The treatment regimen was comprised of ifosfamide at a dose of 5 g/m(2) over 24 hours and L-Dauno at a dose of 100 mg/m(2) every 4 weeks with granulocyte-colony-stimulating factor support. RESULTS: Eleven (31%) of 35 anthracycline/ifosfamide-naive patients achieved a partial/complete response, 6 patients (17%) had stable disease, and 13 patients (37%) had disease progression. Three patients were not evaluable, and there were two intermittent deaths. The median time to disease progression was 6 months, the median overall survival was 14 months, and the median time to treatment failure was 15 months. Toxicity was tolerable. CONCLUSIONS: The combination of Ifosfamide and L-Dauno was found to be a highly active chemotherapy regimen for first-line treatment of soft tissue sarcoma. Therefore, we believe randomized studies with this regimen are warranted.