Multicentric, observational, transversal study to describe the clinical profile of patients with metastatic breast cancer (MBC) treated with first-line bevacizumab (TRANSBREAST): Preliminary results.

Abstract

1143 Background: Following the approval of bevacizumab for the treatment of MBC, this study was devised to identify the profile of patients (pt) treated under real conditions of use, their relationship with the regime used and the MBC subtypes by their genetic signature and tolerability of treatment. Methods: Multicentric observational transversal study in 40 centers. We present the results from the first 108 pts who received at least one dose of bevacizumab. Results: Of the women treated, 98.1% were Caucasian, with a mean age of 50.7 years (30-82) and ECOG 0-1 in 88%. In terms of prior history, 3.7% suffered from cardiopathies, 11.1% vascular disorders and 4.8% had kidney pathology. Neoadjuvant or adjuvant chemotherapy (CT) was given to 88% of them. The predominant histology was infiltrating ductal (82%) and histological grade 3 (49%). Positive results for hormone receptors were found in 68.5%, of which 65% were luminal A and 3.5% luminal B; 3.5% were HER2 positive, while 28% were triple negative. The disease-free interval for patients who received adjuvant or neoadjuvant CT was greater than 12 months in 86.3%. The most frequent metastatic locations were liver (38%), bone (59%), and lung (29%). The drugs most commonly used with bevacizumab were taxanes (87%). Of the 71 pt evaluated so far, 59.2% have shown a response (95% CI: 47-71%), 8.5% complete, and 22% stable disease, with 81.7% (95% CI: 73-91) obtaining a benefit from the treatment, without differences being found between subtypes. The main grade 1-2 toxicities were arterial hypertension (17%) and bleeding (18.5%). One case of grade 3-4 toxicity (proteinuria) was detected although only 30% of patients had a urine analysis. Conclusions: Bevacizumab combined with chemotherapy is well-tolerated, safe, and effective as first-line treatment of MBC, with a clinical benefit being obtained in 81.7% of patients. The results are consistent with the data from the three phase III studies in 1L and MO19391 from the clinical practice. No significant financial relationships to disclose.