SAN ANTONIO – NabTM-paclitaxel (Abraxane), used in tandem with gemcitabine and epirubicin, is showing good anti-tumor activity and tolerability as neoadjuvant treatment for women with locally advanced breast cancer, according to phase II results released at the 2008 San Antonio Breast Cancer Symposium (SABCS).

Nab-paclitaxel is a novel albumin-bound paclitaxel, an established chemotherapy agent, combined with albumin, a very small naturally-occurring protein.

Denise A. Yardley, MD, Director of Breast Cancer Research at the Sarah Cannon Research Institute in Nashville, Tennessee, and colleagues presented results in 123 women who were treated with a bi-weekly schedule of neoadjuvant nab-paclitaxel (nab-P) with gemcitabine and epirubicin.

The trial included women with locally advanced adenocarcinoma of the breast appropriate for neoadjuvant therapy as defined by the presence of a clinical T1c-T4d and/or NO-3 diagnosis with no evidence of distant metastases; an ECOG defined performance status of 0-2; and normal left ventricular function.

Patients underwent six cycles of neoadjuvant gemcitabine (2000 mg/m2 ) epirubicin (50 mg/m2) and nab-paclitaxel ( 175 mg/m2 ) every 14 days followed by surgery. Post- operative therapy included four cycles of (gemcitabine 2000 mg/m2 and nab-paclitaxel (220 mg/m2 ) given once every four days. Myeloid growth factors were required with all treatment cycles.

Overall, 112 patients were available for a pathological response assessment.

Results showed that 22 (18 percent) patients achieved a confirmed pathological response and 84 (68 percent) patients achieved a partial response. The overall survival at 24 months was estimated to be 88 percent, with an estimated 24-month progression-free survival of 71 percent.

Secreted protein acidic rich in cysteine (SPARC) level 3 immunohistochemical staining was observed in 61 (85 percent) of 82 tumors.

Grade 3 or 4 adverse events that were reported in greater than five percent of patients included neutropenia in 11 percent of patients, thrombocytopenia in six percent, arthralgias in seven percent, fatigue in eight percent, and infection in seven percent. Eleven patients did not undergo breast surgery, three patients had disease progression, seven patients were not evaluable, and one patient declined.

Contrary to reports in the literature, SPARC-positive patients in this trial showed a trend towards improved progression-free survival.

“The neoadjuvant combination tested in this trial is active and better tolerated than other gemcitabine/anthracycline/taxane combinations”, Dr. Yardley noted. Importantly, the pathological complete response rate of 18 percent compares favorably with other comparable neoadjuvant regimens albeit with minimal toxicity.

Finally, she said that these preliminary results, if corroborated in larger, controlled trials, may support a role for nab-paclitaxel as an important addition combination therapy used in the neoadjuvant setting.

Abraxane

Written by Jill Stein
Jill Stein is a Paris-based freelance medical writer.
jillstein03(at)gmail.com