Dual HER2 blockade with pertuzumab (P) and trastuzumab (T) in patients with HER2-positive metastatic breast cancer (mBC) relapsing after adjuvant treatment with T: results from a German non-interventional study (NIS) HELENA (NCT01777958)

PURPOSE: NIS HELENA documented outcomes in clinical routine practice of first-line therapy with P plus T and docetaxel (D) of patients with advanced HER2-positive BC and prior (neo)adjuvant T. METHODS: Between 06/2013 through 07/2016, 126 patients (in-label use of P at study start = full analysis set, FAS) in 81 German study sites were included. Intense documentation period was limited to 28 treatment cycles. Maximum follow-up (FU) was 24 months (mos). Safety was assessed in the safety set (SAF = eligible patients with at least one dose of P, n = 132). Median progression-free survival (PFS) was the main parameter of interest. RESULTS: Mean age of FAS patients was 55.1 [30.7–80.2] years, 81.7% (95.2%) were < 65 (75) years of age. 51.6% of the FAS patients were hormone receptor-positive (HR+), 91.3% had distant, 73.0% visceral, and 18.3% non-visceral metastases. Median disease-free interval was 40.2 [6.6–95.9] mos. Effectiveness (FAS): Median PFS was 18.8 [15.1; 24.2] mos. Overall response rate was 64.3% (55.6; 72.1). Median overall survival was 55.9 mos [41.2, not reached]. Safety (SAF): 93.9% of patients had an adverse event (AE), 32.6% a serious AE (SAE). AEs related to P occurred in 53.8% of SAF, SAEs related to P in 13.6%. Diarrhea was the most frequently reported related (S)AE. There were 8 (6.1%) patients with a fatal AE. CONCLUSION: Based on the outcomes from NIS HELENA, results of dual blockade with P+T in patients relapsing after (neo)adjuvant T as reported from the CLEOPATRA study (NCT01777958) can be transferred to routine clinical practice. No new safety signals were detected.