Daiichi Sankyo Announces Two Lancet Oncology Publications of Phase 1 Dose Expansion Results of [Fam-] Trastuzumab Deruxtecan in HER2 Positive Metastatic Breast and Gastric Cancer
- 20.7 months median duration of response achieved in patients with HER2 positive metastatic breast cancer previously treated with T-DM1
- 7.0 months median duration of response achieved in patients with HER2 positive metastatic gastric cancer previously treated with trastuzumab
BASKING RIDGE, New Jersey and MUNICH, April 29, 2019 /PRNewswire/ -- Daiichi Sankyo Company, Limited (hereafter, Daiichi Sankyo) and AstraZeneca today announced the publication of two manuscripts in The Lancet Oncology reporting long-term phase 1 safety and efficacy results of [fam-] trastuzumab deruxtecan (DS-8201). The investigational HER2 targeting antibody drug conjugate (ADC) was evaluated in heavily pretreated patients with HER2 positive metastatic breast cancer and gastric cancer.
HER2 Positive Breast Cancer Results
The first manuscript reports efficacy results for 115 patients who received at least one dose of [fam-] trastuzumab deruxtecan, of which 111 were evaluable for confirmed response. These patients with HER2 positive metastatic breast cancer previously treated with ado-trastuzumab emtansine (T-DM1) received [fam-] trastuzumab deruxtecan at a recommended expansion dose of 5.4 or 6.4 mg/kg in the dose escalation or dose expansion parts of the phase 1 study. Patients enrolled in this part of the study had a median of seven prior anticancer regimens, including T-DM1 and trastuzumab, and in 86 percent of cases, pertuzumab.
A confirmed objective response rate of 59.5 percent [95 percent CI: 49.7-68.7] and a disease control rate of 93.7 percent [95 percent CI: 87.4-97.4] was observed with [fam-] trastuzumab deruxtecan. Median duration of response was 20.7 months (range 0.0-21.8), median progression-free survival was 22.1 months (range 0.8-27.9), and median overall survival has not yet been reached in the study. Fifty-five (48 percent) patients remain on treatment with [fam-] trastuzumab deruxtecan, as of data cut-off on August 10, 2018.
"For patients with HER2 positive metastatic breast cancer that progresses after trastuzumab, pertuzumab, and T-DM1, optimal treatment is not clearly defined and choices may be limited," said Kenji Tamura, MD, PhD, Department of Breast and Medical Oncology National Cancer Center Hospital, Tokyo, Japan, and lead author on the study. "These results demonstrate preliminary clinically meaningful response rates with an impressive duration of response, supporting further development and suggesting a potential role for [fam-] trastuzumab deruxtecan as a HER2 targeted therapy option in this setting."