(Breast Cancer) DS-8201a at ESMO 2016

• October 28, 2016
• Reading time: 1 minute

At ESMO 2016, Dr. Kenji Tamura of the National Cancer Center Hospital Japan presented results demonstrating that DS-8201a — an anti-HER2 antibody-drug conjugate — showed efficacy in breast cancer and gastric cancer. DS-8201a is a compound that links an anti-HER2 antibody with DXd, a topoisomerase inhibitor. In animal models, it demonstrated activity even in tumors resistant to T-DM1 (ado-trastuzumab emtansine).

The drug has progressed to human clinical trials targeting breast cancer, gastric cancer, and gastroesophageal junction adenocarcinoma patients in a Phase 1 study administered every three weeks. Phase 1 consisted of toxicity testing with gradual dose escalation, enrolling Japanese and American patients, with subgroups including low-HER2 patients and solid tumor patients other than breast or gastric cancer. At the time of this presentation, Phase 1 data from 22 of 23 enrolled patients (median age 66 years) was reported: 16 breast cancer patients (73%), 5 gastric cancer patients (23%), and 1 GEJ adenocarcinoma patient (5%).

Dose levels tested: 0.8, 1.6, 3.2, 6.4, and 8.0 mg/kg. Three patients received 8.0 mg/kg, of whom two subsequently had their dose reduced.

Safety results: No Grade 4 adverse events or life-threatening events were observed. Seven Grade 3 adverse events occurred: hypocalcemia, anemia, lymphopenia, and cholangitis. All participants completed subsequent treatment cycles without discontinuation due to adverse events.

Efficacy results: Among 20 evaluable patients (12 previously treated with T-DM1, 5 with low HER2 expression), 7 achieved partial response (PR), with a disease control rate (DCR) of 90%. Among prior T-DM1 recipients, the response rate was 18% and DCR was 64%. With continued DS-8201a treatment, the response rate was 42% and DCR was 92%. All PR patients received doses of 5.4 mg/kg or higher.

An expansion cohort at 6.4 mg/kg every three weeks is currently ongoing.

Tags: #BreastCancer #GastricCancer

• Clinical trial drug

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