Final results from PERUSE, a global study of pertuzumab (P), trastuzumab (H) and investigator’s chosen taxane as first-line therapy for HER2-positive locally recurrent/metastatic breast cancer (LR/mBC)

Background P + H + docetaxel (DOC) is the standard first-line therapy for HER2-positive LR/mBC, based on results from the phase 3 CLEOPATRA trial. The single-arm PERUSE study (NCT01572038) assessed the safety and efficacy of P + H with investigator-selected taxane in this setting. We present final safety and efficacy results.

Methods Patients (pts) with inoperable HER2-positive LR/mBC and no prior systemic therapy for LR/mBC (except endocrine therapy [ET]) received DOC, paclitaxel (PAC) or nab-PAC with H + P until disease progression or unacceptable toxicity. Primary endpoint was safety. Progression-free survival (PFS) and overall survival (OS) were secondary endpoints. Subgroup analyses according to taxane and hormone receptor (HR) status were prespecified.

Results 1436 pts were treated. At data cut-off (26 Aug 2019), median follow-up was 69 mo (range 0-87). The safety profile and efficacy results were consistent with CLEOPATRA. Grade ≥3 adverse events (AEs) occurred in 61% of pts (10% neutropenia, 8% diarrhoea) and were considered related to P in 20%, H in 17% and taxane in 36%. Median PFS was ~21 mo, irrespective of HR status. 295 pts (21%) received maintenance ET. 679 pts (47%) received post-study anticancer therapy (monoclonal antibodies in 34%: 25% H, 19% T-DM1, 7% P).

Conclusions Final results from PERUSE are consistent with CLEOPATRA, support first-line P + H + taxane therapy for HER2-positive LR/mBC and suggest PAC as a valid alternative to DOC as backbone chemotherapy.