Weekly First-Line Abraxane Yields Benefit

March 1, 2007

Weekly first-linetherapy with nab-paclitaxel (Abraxane)was well tolerated and showed strongclinical responses in taxane-refractorylocally advanced or metastatic breast cancer,report researchers from the InternationalOncology Network.

DALLAS–Weekly first-linetherapy with nab-paclitaxel (Abraxane)was well tolerated and showed strongclinical responses in taxane-refractorylocally advanced or metastatic breast cancer,report researchers from the InternationalOncology Network (abstract6073). Lead investigator Barry C.Mirtsching, MD, discussed the phase IIopen-label nonrandomized study.

Patients received nab-paclitaxel at 125mg/m2 on days 1, 8, and 15 of a 28-daycycle. HER2-positive patients wereallowed to receive trastuzumab(Herceptin), and underwent cardiacmonitoring at regular intervals. A medianof 4 cycles of chemotherapy (range 1to 15) were administered, and dose wasreduced in about one-fourth of patients,due to toxicity. At analysis, 67 patientshad been treated, and 35 (1 male) wereevaluable for response; 25 were HER2-negative, 9 were HER2-positive, andHER2 status was unavailable for 1 patient.The primary endpoint was ORR.

Good Efficacy, Safety

The CR/PR was 74.3% (26 patients).An additional 8 patients had stable disease.Median time to objective responsewas 3.5 months. Median TTP was 12.6months, and overall survival at 14months (median OS not reached at analysis)was 71.2%.

The CR/PR was 74.3% (26 patients).An additional 8 patients had stable disease.Median time to objective responsewas 3.5 months. Median TTP was 12.6months, and overall survival at 14months (median OS not reached at analysis)was 71.2%.

Dr. Mirtsching and colleagues reportedthat the most common grade 3 toxicitieswere neutropenia (10.4% of patients);neuropathy (6.0%); fatigue(4.5%); and muscle weakness, joint pain,dyspnea, and thrombosis (all at 3%).Grade 4 toxicities were supraventriculartachycardia and vascular disorder, eachoccurring in 1.5% of evaluable patients.

Though the data are preliminary, theinvestigators concluded that they demonstrate"significant efficacy of weeklyAbraxane in the first-line treatment ofmetastatic breast cancer, and a favorablesafety profile."