Open AccessAntitumor Activity and Safety of Trastuzumab Deruxtecan in Patients With HER2-Low–Expressing Advanced Breast Cancer: Results From a Phase Ib Study
Author(s) -
Shanu Modi,
Haeseong Park,
Rashmi Krishna Murthy,
Hiroji Iwata,
Kenji Tamura,
Junji Tsurutani,
Alvaro Moreno-Aspitia,
Toshihiko Doi,
Yasuaki Sagara,
Charles H. Redfern,
Ian E. Krop,
Caleb Lee,
Yoshihiko Fujisaki,
Masahiro Sugihara,
Lin Zhang,
Javad Shahidi,
Shunji Takahashi
Publication year - 2020
Publication title -
journal of clinical oncology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.482
H-Index - 548
eISSN - 1527-7755
pISSN - 0732-183X
DOI - 10.1200/jco.19.02318
Subject(s) - medicine , adverse effect , trastuzumab , breast cancer , gastroenterology , anemia , refractory (planetary science) , phases of clinical research , toxicity , neutropenia , cancer , oncology , astrobiology , physics
PURPOSE Trastuzumab deruxtecan (T-DXd, formerly DS-8201a) is a novel human epidermal growth factor receptor 2 (HER2)-targeted antibody drug conjugate (ADC) with a topoisomerase I inhibitor payload. A dose escalation and expansion phase I study evaluated the safety and activity of T-DXd in patients with advanced HER2-expressing/mutated solid tumors. Here, results for T-DXd at the recommended doses for expansion (RDE) in patients with HER2-low (immunohistochemistry [IHC] 1+ or IHC 2+/in situ hybridization−) breast cancer (ClinicalTrials.gov identifier: NCT02564900 ) are reported.PATIENTS AND METHODS Eligible patients had advanced/metastatic HER2-low–expressing breast cancer refractory to standard therapies. The RDE of 5.4 or 6.4 mg/kg T-DXd were administered intravenously once every 3 weeks until withdrawal of consent, unacceptable toxicity, or progressive disease. Antitumor activity and safety were assessed.RESULTS Between August 2016 and August 2018, 54 patients were enrolled and received ≥ 1 dose of T-DXd at the RDE. Patients were extensively pretreated (median, 7.5 prior therapies). The confirmed objective response rate by independent central review was 20/54 (37.0%; 95% CI, 24.3% to 51.3%) with median duration of response of 10.4 months (95% CI, 8.8 month to not evaluable). Most patients (53/54; 98.1%) experienced ≥ 1 treatment-emergent adverse event (TEAE; grade ≥ 3; 34/54; 63.0%). Common (≥ 5%) grade ≥ 3 TEAEs included decreases in neutrophil, platelet, and WBC counts; anemia; hypokalemia; AST increase; decreased appetite; and diarrhea. Three patients treated at 6.4 mg/kg suffered fatal events associated with T-DXd–induced interstitial lung disease (ILD)/pneumonitis as determined by an independent adjudication committee.CONCLUSION The novel HER2-targeted ADC, T-DXd, demonstrated promising preliminary antitumor activity in patients with HER2-low breast cancer. Most toxicities were GI or hematologic in nature. ILD is an important identified risk and should be monitored closely and proactively managed.