BRCA1 and breast cancer: However, a phase II study evaluating olaparib 400 mg twice a day as a single agent for patients with advanced breast cancer (n = 26, 81% TNBC) did not report any confirmed responses in BRCA1/2 mutation neither positive (n = 10) nor negative (n = 16) subjects, even though the target lesions were reduced in size by >30% in 5 out of 10 (50%) patients with BRCA1 or BRCA2 mutations, but were not confirmed objective responders because of absence of confirmation at the next visit (three patients) or progression of nontarget or new lesions at the same visit (two patients) [108].