UPDATE 1-Sanofi breast cancer drug gets FDA fast-track nod

* Phase 2 median survival 12.2 months for treatment arm

* Phase 3 trial on schedule

LOS ANGELES Dec 11 (Reuters) - French drugmaker Sanofi-Aventis SA (SASY.PA) said on Friday U.S. regulators will review its BSI-201 experimental breast cancer drug on an accelerated basis and that a pivotal trial of (the?) drug is on schedule.

The fast-track designation from the U.S. Food and Drug Administration means the agency will accept initial late-stage data instead of waiting for entire Phase III clinical trial results.

Experimental drugs seeking approval from the agency are granted this designation when they are intended for treatment of a serious or life-threatening disease and demonstrate the potential to address unmet needs for such a condition.

BSI-201 is being studied in women with "triple negative" metastatic breast cancer, meaning their tumors do not respond to typical hormonal therapies or drugs that target a protein called HER-2.

Sanofi said an ongoing Phase 2 trial of the drug has found that women who received BSI-201 had a median survival of 12.2 months, compared with 7.7 months for the chemotherapy-only group. The company said the results are not final.

"Median survival has not yet been reached in the BSI-201 arm, therefore the data cut-off period for the Phase 2 trial from September to November," Sanofi said in a statement.

The drug is designed to work by blocking a cell repair enzyme known as PARP.

The company said study investigators have enrolled 214 of the target number of 420 patients in the Phase 3 trial.

(Reporting by Deena Beasley; Editing by Richard Chang)