Abstract 236P
Background
Trastuzumab deruxtecan (TDXd) demonstrated unprecedented efficacy in patients (pts) with HER2+ metastatic breast cancer after at least a prior anti-HER2 regimen. However, few data are available about its efficacy in routine clinical practice. In this multicenter retrospective study we evaluated effectiveness and safety of TDXd in a real-world (rw) population.
Methods
Clinical and pathological information about pts with HER2+ mBC who received TDXd were collected from 11 italian hospitals. Activity and toxicity were evaluated following RECIST 1.1 and CTCAE v5 criteria. The survival outcomes evaluation included PFS, milestone-PFS and OS.
Results
One hundred forty-three patients were enrolled. Median age was 66 (range 33-84) and 4 men were included. Estrogen receptor (HR) was positive in 108 (75%) pts and negative in 35 (25%). TDXd was administered as first, second, third or subsequent line in 4 (3%), 16 (11%), 42 (29%), and 81 (57%) pts respectively. Among 123 pts with measurable disease, the ORR was 68% and the disease control rate was 91% (9 CRs, 74 PRs, and 30 SD). Nine (7%) pts had primary resistance to TDXd. With a median follow-up of 12 months (range: 1-31), the mPFS was 16 months. PFS was 84%, 59%, and 39% at 6, 12, and 18 months, respectively. A favorable trend in PFS was reported in pts receiving TDXd as I/II line vs further lines, though the difference did not reach statistical significance (17 vs 15 months, 76% vs 56%; p=0.098). OS was 90.8% at 6 months, 74% at 12, and 59% at 18 months, respectively. Median OS was 20 months. 89% of pts who received TDXd as I/II line were alive at 12 months vs 73% of subsequent lines (p=0.39). Any-grade toxicity was registered in 84 patients (59%). The most common toxicities reported were nausea (33%), neutropenia (21%), and asthenia (21%). Liver toxicity and diarrhea were uncommon (5%, and 1% respectively). Severe toxicities were registered in 18% of pts and the most frequent were neutropenia, nausea/vomiting, and interstitial lung disease observed in 15, 2 and 3 pts, respectively. Adverse events led to dose reduction in 37 pts (26%).
Conclusions
The efficacy and safety of TDXd were confirmed in an unselected real-world population. These results are consistent with the registrative trials and no new safety concerns were reported.
Legal entity responsible for the study
Andrea Botticelli.
Funding
Has not received any funding.
Disclosure
A. Botticelli: Financial Interests, Personal, Advisory Board: Roche, Novartis, MSD, Lilly, Pfizer, Amgen, BMS, Gilead; Financial Interests, Personal, Invited Speaker: Sofos. S. Pisegna: Financial Interests, Personal, Invited Speaker: Eli Lilly, Novartis, Pfizer, Roche, AstraZeneca. S. Scagnoli: Financial Interests, Personal, Invited Speaker: Novartis, Lilly, MSD, Pfizer, BMS. M. De Laurentiis: Financial Interests, Personal, Speaker’s Bureau: Roche, Celgene, MSD; Financial Interests, Personal, Advisory Board: AstraZeneca, Amgen, Eisai, Exact Science, Gilead, Novartis, Pfizer, Pierre Fabre, Roche; Financial Interests, Personal, Invited Speaker: Daiichi Sankyo, Eli Lilly, Seagen. R. Caputo: Financial Interests, Personal, Invited Speaker: Roche, Eli Lilly, MSD, Gilead, Daiichi; Financial Interests, Personal, Advisory Board: Novartis, Pierre-Fabre. M. Palleschi: Financial Interests, Personal, Advisory Board: Novartis, Lilly. A. Orlandi: Financial Interests, Personal, Invited Speaker: Amgen, Pfizer, Daiichi Sankyo; Financial Interests, Personal, Advisory Board: Lilly, Novartis, Gilead. M. Giampaglia: Financial Interests, Personal, Invited Speaker: Novartis, Eli Lilly. M.A. Fabbri: Financial Interests, Personal, Invited Speaker: Eli Lilly, Novartis, Pfizer; Financial Interests, Personal, Advisory Board: Roche, Gilead. G. D'Auria: Financial Interests, Personal, Advisory Board: Eisai, Amgen, Pfizer, Lilly, Novartis. P. Vici: Financial Interests, Personal, Advisory Board: Novartis, Pfizer; Financial Interests, Personal, Invited Speaker: Eli Lilly, Eisai. P. Marchetti: Financial Interests, Personal, Advisory Role: BMS, Roche, Genentech, MSD, Novartis, Amgen, Merck, Pierre Fabre, Incyte. A. Fabi: Financial Interests, Personal, Advisory Board: Roche, Novartis, Pfizer, Gilead, Sophos, Seagen, AstraZeneca, Lilly, Pierre Fabre, Exact Science. All other authors have declared no conflicts of interest.