CHICAGO―Low-dose weekly paclitaxel and standard every-other-week paclitaxel dosing offer equivalent postsurgical progression-free survival (PFS) rates among women with higher-risk early-stage breast cancer, report authors of a randomized phase 3 clinical trial presented at the 2013 American Society of Clinical Oncology (ASCO) Annual Meeting.

But because weekly dosing was associated with less toxicity and “should ultimately be associated with lower cost due to less use of granulocyte colony stimulating factor,” ASCO breast cancer spokesperson Andrew D. Seidman, MD, predicted that many clinicians would be moving to weekly dosing in light of the study.

“Our results suggest that either regimen will give a good outcome, but the weekly schedule seems to result in better quality of life for patients, causing less muscle and bone pain, and allergic reactions,” reported lead author G. Thomas Budd, MD, of the Cleveland Clinic in Cleveland, OH, and coauthors .

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The S0221 trial compared the two adjuvant paclitaxel schedules. A total of 2,716 patients diagnosed with node-positive or high-risk node-negative operable breast cancer were randomly assigned to receive either standard-dose (175 mg/m2) treatment administered every 2 weeks for 12 weeks with pegfilgrastim support, or a low-dose weekly regimen (80 mg/m2) for 12 weeks, Dr. Budd reported.

Both dosing schedules were “equally effective in preventing breast cancer progression,” Dr. Budd said (hazard ratio [HR], 1.08; 95% CI: 0.90-1.28; P=0.42). Dr. Budd reported 5-year PFS rates of 82% for weekly paclitaxel and 81% for the standard-dose regimen.

There were a total of six treatment-related deaths: four on standard-dose paclitaxel and two among patients administered the weekly regimen. Grade 3 or 4 toxicities including allergy (standard, 14% vs weekly 6%); musculoskeletal pain (11% vs 3%); neurologic toxicities (17% vs 10%); dermatologic (3% vs 0.1%); and leukopenia, in which the weekly regimen was associated with a higher risk (1% vs 6%), Dr. Budd reported.