T-DM1 improved outcomes in pts with HER2+ MBC, but few data concerning its use in routine clinical practice are available.
We retrospectively enrolled 194 HER2+ (IHC 3+ or 2+ amplified) MBC pts treated with T-DM1 in real-world practice in 20 Italian oncologic centers.
Baseline pts and tumors characteristics are listed in Tab 1. Median (m) follow up was 9.8 months (mo) (range,2-37), m T-DM1 treatment duration was 5 mo (range, 1-30). Among 183 evaluable pts, 5.4% had a complete response and 35% a partial response, for an Overall Response Rate of 40% (95%CI, 33-47). A stable disease (SD) was recorded in 26.8% pts, with a clinical benefit (CB: response or SD lasting ≥ 6 mo) of 55% (95%CI, 47-62). No significant differences in responses have emerged according to disease sites. M Progression Free Survival (PFS) was 6 mo (95%CI, 5-7), m Overall Survival (OS) was 35 mo (95%CI, 11-59). Pts who have previously carried out ≤3 lines for MBC had improved PFS (p = 0.006). At multivariate analysis, factors related to PFS benefit were lower ECOG performance status (PS) (p
In this real-world setting of heterogeneous HER2+ MBC pts, efficacy of T-DM1 was comparable with that reported in phase II-III studies, without new safety issues.
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All authors have declared no conflicts of interest.