Protein-Bound Paclitaxel Promising as First-Line Treatment in Non-Small-Cell Lung Cancer

Abraxis BioScience Inc presented data at the American Society of Clinical Oncology (ASCO) annual meeting from multiple phase II studies with paclitaxel albumin-bound particles for injectable suspension (Abraxane) as first-line treatment for late-stage non-small-cell lung cancer (NSCLC). In a series of dose-ranging and efficacy studies, albumin-bound paclitaxel as first-line treatment showed improved antitumor benefits over the solvent-based taxane treatment. These data form the basis for a phase III registration trial, which is expected to begin in the second half of 2006.

"These data in NSCLC are consistent with the clinical trial experience with Abraxane in the breast cancer setting, where Abraxane demonstrated greater antitumor activity than Taxol [standard paclitaxel]," said Michael Hawkins, MD, chief medical officer of Abraxis BioScience. "We look forward to advancing Abraxane into larger pivotal trials to develop more active treatment regimens for critically ill cancer patients."

"These early studies show efficacy results that seem to be better than typically seen with solvent-based taxane therapy in advanced lung cancer treatment", said Mark A. Socinski, MD, associate professor of medicine, Lineberger Comprehensive Cancer Center, University of North Carolina School of Medicine. "This is potentially hopeful news for patients with advanced non-small-cell lung cancer, a setting in which we see limited treatment options."

Combined With Carboplatin

In one of three ongoing phase II studies presented, chemotherapy-naive patients (n = 56) with stage III/IV NSCLC received weekly albumin-bound paclitaxel (100 mg/m

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) and carboplatin (area under the curve [AUC] 6). Half of the patients had either a complete or partial response, and an additional 36% had stable disease for at least 12 weeks, resulting in a disease control rate of 86%; median time to disease progression was 28 weeks. By comparison, previous clinical trial experience with solvent-based paclitaxel given weekly and standard carboplatin demonstrated a 32% response rate in a similar patient population. The grade 3/4 adverse events observed with albumin-bound paclitaxel were neutropenia, thrombocytopenia, and anemia.

Dose-Escalation Trial

Other data presented from another trial included a phase I/II study of albumin-bound paclitaxel as a first-line single-agent treatment for patients (n = 40) with advanced NSCLC. In the first phase of the dose-escalating trial, a weekly maximum tolerated dose of 125 mg/m

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was established. In the treatment phase of the trial, 30% of patients had an objective response, and median survival was 10.9 months. Hematologic toxicity was minimal, and the most common grade 3 toxicities were fatigue and sensory neuropathy.

Every-3-Week Regimen

A third phase II study involved dose escalation exploring the use of albumin-bound paclitaxel and carboplatin given every 3 weeks in patients (n = 100) with advanced NSCLC as first-line therapy. This trial demonstrated a 29% response rate across all doses and a 46% disease control rate for 16 weeks or longer. The most common grade 3/4 toxicities were neutropenia, anemia, and thrombocytopenia, although no clear relationship between the dose of albumin-bound paclitaxel and severe myelosuppression was established. The occurrence of sensory neuropathy was dose-dependent, and no grade 4 sensory neuropathy was observed.