Bevacizumab plus chemotherapy improves response rates and prolongs PFS when used as first- and second-line therapy for advanced breast cancer. However, bevacizumab has not improved OS in the individual studies currently reported. In Europe, EMA has maintained its indication associated with weekly paclitaxel in first line metastatic breast cancer and more recently with capecitabine based on RIBBON 1 trial's results.

The identification of patient subsets that receive the most clinical benefit would enable more specific treatment administration of bevacizumab and allow patients unlikely to benefit the opportunity to seek other treatment modalities. Unfortunately, despite efforts to identify patient subsets with a differential benefit from bevacizumab, no validated biomarkers have been defined.

The Avastin cohort is a unique opportunity to investigate various biological and imaging parameters which could be related to clinical benefit of the combination of bevacizumab and weekly paclitaxel in first line metastatic breast cancer in a homogeneously treated population in French cancer centers. This trial will gather the expertise of several translational research platforms of different cancer centers from the UNICANCER consortium.

Inclusion Criteria:

• Male or female ≥18 years old.
• Histologically confirmed breast adenocarcinoma, metastatic (measurable or unmeasurable lesion), HER2 negative (on the last tumor tissue analyzed), Patient to receive first-line chemotherapy paclitaxel and bevacizumab in a weekly manner as recommended by the EMEA.
• Hormone receptor status known
• Eastern Cooperative Oncology Group (ECOG) performance status ≤2.
• Life expectancy ≥12 weeks.
• Women of childbearing age (except amenorrhea of at least 24 months) must have a negative pregnancy test serum within 28 days before starting treatment. In the absence of serum test, a urine pregnancy test (within 7 days before the first dose of bevacizumab) is required.
• Informed consent form duly signed and dated by patient

Exclusion Criteria:

• Prior chemotherapy for metastatic disease ;
• Concomitant hormone therapy
• The patient must not have undergone radiation therapy for the treatment of metastatic disease (except cases of analgesic radiotherapy for bone pain due to metastases).
• Pregnant or nursing woman or woman of childbearing age (except amenorrhea for at least 24 months) who does not use an effective nonhormonal contraceptive method (intrauterine device, barrier method associated with the use of a spermicidal gel or surgical castration) for the duration of the study and 6 months after paclitaxel administration and / or bevacizumab.
• Man who does not accept to use effective contraception during the study period and 6 months after paclitaxel administration and / or bevacizumab.
• Known hypersensitivity to paclitaxel and / or to bevacizumab or to any excipients.
• Patient unable to undergo medical test for geographical, social or psychological reasons.
• Patient deprived of liberty or placed under the authority of a tutor

metastatic breast cancer

Unicancer will share de-identified individual data that underlie the results reported. A decision concerning the sharing of other study documents, including protocol and statistical analysis plan will be examined upon request.

The data shared will be limit to that required for independent mandated verification of the published results, the applicant will need authorization from Unicancer for personal access, and data will only be transferred after signing of a data access agreement.

Unicancer will consider access to study data upon written detailed request sent to Unicancer, from 6 months until 5 years after publication of summary data.