The interim analysis of the phase IIIb LUCY trial demonstrated the clinical effectiveness
of olaparib in patients with germline BRCA-mutated (gBRCAm), human epidermal growth
factor receptor 2 (HER2)-negative metastatic breast cancer (mBC), with median progression-free
survival (PFS) of 8.11 months, which was similar to that in the olaparib arm of the
phase III OlympiAD trial (7.03 months). This prespecified analysis provides final
overall survival (OS) and safety data.The open-label, single-arm LUCY trial of olaparib
(300 mg, twice daily) enrolled adults with gBRCAm or somatic BRCA-mutated (sBRCAm),
HER2-negative mBC. Patients had previously received a taxane or anthracycline for
neoadjuvant/adjuvant or metastatic disease and up to two lines of chemotherapy for
mBC.Of 563 patients screened, 256 (gBRCAm, n = 253; sBRCAm, n = 3) were enrolled.
In the gBRCAm cohort, median investigator-assessed PFS (primary endpoint) was 8.18
months and median OS was 24.94 months. Olaparib was clinically effective in all prespecified
subgroups: hormone receptor status, previous chemotherapy for mBC, previous platinum-based
chemotherapy (including by line of therapy), and previous cyclin-dependent kinase
4/6 inhibitor use. The most frequent treatment-emergent adverse events (TEAEs) were
nausea (55.3%) and anemia (39.2%). Few patients (6.3%) discontinued olaparib owing
to a TEAE. No deaths associated with AEs occurred during the study treatment or 30-day
follow-up.The LUCY patient population reflects a real-world population in line with
the licensed indication of olaparib in mBC. These findings support the clinical effectiveness
and safety of olaparib in patients with gBRCAm, HER2-negative mBC.Clinical trials
registration number: NCT03286842.
