merck  co inc mrk and astrazeneca plc azn said tuesday that their supplemental new drug application snda for its breast cancer treatment lynparza has been accepted and granted priority review by the us food and drug administration lynparzas snda is for the adjuvant treatment of patients with brcamutated human epidermal growth factor receptor 2negative highrisk early breast cancer who have already been treated with chemotherapy the snda was based on results from a phase 3 trial that showed lynparza demonstrated a statistically significant and clinically meaningful improvement in invasive diseasefree survival reducing the risk of invasive breast cancer recurrence second cancers or death by 42 versus placebo mercks stock slipped 02 in premarket trading but outperformed the 12 drop in futures ym00 for the dow jones industrial average djia ahead of the open