"Short Course" of Nonpegylated Liposomal Doxorubicin Plus Paclitaxel and Trastuzumb as Primary Systemic Therapy for Operable and Locally-Advanced Breast Cancer: A Phase II Study (PacLiDox 07).

BACKGROUND

Schedules with anthracyclines and taxanes are one of the best options for primary chemotherapy. The addition of trastuzumab showed an impressive percentage of pathological complete responses in Buzdar trial (66.7%). Recently, nonpegylated liposome-encapsulated doxorubicin (NLD) has been widely used in advanced breast cancer with high response rates (98.1 % in Cortes study). The aims of our study were to assess pathological responses and toxicity of NLD plus paclitaxel (and trastuzumab in patients with HER2 overexpression).

METHODS

Thirty patients entered the study: 9 locally advanced and 21 operable. Median age was 58.5 years (range: 31-73). 23 patients without HER2 overexpression (or FISH not amplified) were treated with NLD 50 mg/m every three weeks for 3 courses and weekly paclitaxel 80 mg/m for 8 courses. 7 patients with HER2 overexpression or FISH amplified were treated with the same schedules plus trastuzumab (Herceptin) 4 mg/kg for the first administration and 2 mg/kg for the following 7 weekly administrations.

RESULTS

Pathological complete response (pCR) was documented in 1 patient (treated with trastuzumab); no residual tumor (infiltrating or "in situ") on breast was documented in other 2 patients. Objective clinical responses were documented in 22 patients (73.3%): 8 complete, 10 partial and 4 "minimal" responses. 7 patients have shown stable and 1 progressive disease. Clinical response in patients with HER2 overexpression treated with trastuzumab was 100% (4 complete and 3 partial responses). Conservative surgery was performed in 8 (38%) and mastectomy in 13 (62%) out of 21 operable patients; however, 7 out of 14 responding patients with operable disease underwent quadrantectomy (50%). Main toxicity was neutropenia: febrile in 2 patients (7%) and gr. 3-4 in 13 (43%). Other grade 3 toxicities were as follows: vomiting in 1 patient, asthenia in 1 patient, joint symptom in 1 patient. 3 patients were withdrawn from the study. No episodes of left ventricular ejection fraction (LVEF) < 50% were recorded (with a median reduction of 8%).

CONCLUSIONS

A "short course" of paclitaxel and NLD is active in terms of clinical response and conservative surgery for patients with potentially operable and locally advanced breast cancer; toxicity was manageable. High activity of the combination with trastuzumab has been confirmed. However, with this "short course" schedule, the result in term of clinical responses didn't turn into complete pathological responses.