Efficacy and safety of eribulin mesylate vs. docetaxel or paclitaxel, combined with trastuzumab and pertuzumab, as first-line treatment for HER2-positive locally advanced or metastatic breast cancer: updated subgroup analyses of JBCRG-M06/EMERALD.

PURPOSE: We performed updated subgroup analyses of the EMERALD study to investigate efficacy, safety, and quality of life (QoL) in patients treated with eribulin (E) vs. either docetaxel (DTX) or paclitaxel (PTX).

METHODS

Patients with HER2+ locally advanced/metastatic breast cancer (LABC/MBC) were randomized to receive E or taxane (T) (physician's choice of DTX or PTX; declared in advance at registration) in 21-day cycles, each combined with trastuzumab + pertuzumab. Survival outcomes, treatment patterns, antitumor efficacy, safety, and QoL were examined.

RESULTS

The intention-to-treat (and safety) populations comprised 224 (224) patients who received E, 186 (184) who received DTX, and 36 (34) who received PTX. Baseline characteristics were balanced. Progression-free survival (E vs. DTX: 14.0 vs. 13.1 months; hazard ratio [HR], 0.94 [95% CI, 0.74-1.21]; E vs. PTX: 14.1 vs. 10.8 months; HR, 1.00 [95% CI, 0.58-1.73]) and overall survival (E vs. DTX: not reached [NR] vs. NR; E vs. PTX: 75.5 months vs. NR) were similar among the subgroups. Although the incidences of adverse events (AEs) were generally similar, peripheral sensory neuropathy was more frequent with PTX and less frequent with DTX, compared with E. Neutropenia tended to be more frequent with E. Median time to QoL deterioration was longer with E vs. DTX (7.8 vs. 4.7 months) and E vs. PTX (6.1 vs. 3.9 months).

CONCLUSIONS

This trial revealed comparable efficacy of E vs. either DTX or PTX, when combined with dual HER2 blockade as first-line treatment for HER2+ LABC/MBC. AEs were generally similar between the E and T subgroups. QoL was maintained for longer in the E subgroups vs. T subgroups.

TRIAL REGISTRATION: ClinicalTrials.gov (NCT03264547; registered: 28 June 2017); University Hospital Medical Information Network (UMIN000027938; registered: 26 June 2017).