Antitumor activity reported for ABI-007 in patients resistant to taxane.

2003 JUL 3 - (NewsRx.com & NewsRx.net) -- At the recent American Society of Clinical Oncology (ASCO) meeting, American Pharmaceutical Partners, Inc., (APPX) said investigators reported on the early findings in a phase II metastatic breast cancer trial of ABI-007, a novel Cremophor-free protein engineered nanoparticle paclitaxel, and results of intra-arterial ABI-007 in phase II trial in head and neck cancer patients as well as patients with cancers of the pelvis

Patients were eligible to enter the phase II metastatic breast cancer trial if they had shown ongoing growth of their tumor even after receiving either Taxol and/or Taxotere therapy. In this refractory or resistant population, ABI-007 was administered weekly, at a dose of 100 mg/m[superscript]2 over 30 minutes, without steroid pretreatment, and was found to be well tolerated with positive evidence of antitumor activity, despite prior progression of tumor growth in these patients after prior taxane therapy.

Following weekly ABI-007 administration, a reduction of tumor size by at least 50% was confirmed in 18% (5/28) of the patients evaluated to date with duration of response ranging from 6 months to over 10 months despite their demonstrated resistance to current taxane therapy. Furthermore, 21% (6/28) of these patients to date currently remain progression-free for over 8 months, with two currently progression-free for over 10 months, and all six patients remain ongoing in the study receiving weekly dosing of ABI-007.

With regard to safety, the investigators noted that at the dose of 100 mg/m[superscript]2 weekly, ABI-007 was well tolerated with no patients showing grade 3 or 4 neuropathy; only 4% of patients showing evidence of grade 4 neutropenia (without growth factor support); and no patients displaying any evidence of allergic reactions at any grade despite the fact that no steroid premedication was given. The most common adverse events reported were mild in nature and included those typical of taxane therapy including alopecia, nausea, and fatigue.

"The findings of both prolonged duration of response with ABI-007 in this refractory breast cancer patient population, as well as the extremely low incidence of toxicity of this novel nanoparticle paclitaxel is impressive," stated Joanne Blum, MD, director, Hereditary Cancer Risk Program and Research Site Leader, Baylor-Sammons Cancer Center, U.S. Oncology, Dallas, TX, and Principal Investigator of the phase II trial.

The Protosphere Nanoparticle technology integrates biocompatible proteins with drugs to create the nanoparticle form of the drug having a size of about 100-200 nanometers (approximately 1/100th the size of a single red blood cell). This novel Protosphere Nanoparticle technology, developed by American Bioscience, Inc., (ABI), has been tested for administration of drugs by intravenous, intra-arterial, inhalational, oral and topical use. These protein-engineered nanoparticles avoid the use of toxic solvents and emulsifiers commonly utilized for administration of insoluble drugs e.g., paclitaxel and docetaxel, the active ingredients in Taxol and Taxotere respectively. ABI-007 is the nanoparticle form of the drug paclitaxel, engineered ...