The following article features coverage from the American Society of Clinical Oncology 2020 meeting. Click here to read more of Cancer Therapy Advisor‘s conference coverage.

Trastuzumab deruxtecan (T-DXd), an antibody-drug conjugate, demonstrated positive results as a treatment for HER2-positive advanced gastric cancer or gastroesophageal junction (GEJ) adenocarcinoma in patients whose disease progressed despite 2 or more prior lines of therapy. These findings were presented during the ASCO 2020 Virtual Scientific Program.

An open-label multicenter, randomized phase 2 trial (DESTINY-Gastric01; ClinicalTrials.gov Identifier: NCT03329690) found that T-DXd treatment was associated with a better objective response rate (ORR) and prolonged overall survival (OS) compared with standard chemotherapy with either irinotecan or paclitaxel.

The study, led by Kohei Shitara, MD, from the National Cancer Center Hospital East in Japan, included 187 patients. Of those, 125 were treated with T-DXd and 62 received either irinotecan or paclitaxel at their physicians’ discretion. Study patients had a median of 2 prior lines of therapy and 44.4% had 3 lines of therapy or more, the investigators reported.

As of a data cutoff on November 8, 2019, 22.4% of patients in the T-DXd group and 4.8% of those in the comparison group remained on treatment. The unconfirmed ORR — the study’s primary end point — was 51.3% in the T-DXd arm compared with 14.3% in the standard-chemotherapy arm (P <.0001). The confirmed ORR was 42.9% and 12.5%, respectively (P <.0001).


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Median OS was 12.5 months in the T-DXd arm compared with 8.4 months in the standard-chemotherapy group. T-DXd treatment was significantly associated with a 41% decreased risk of death (95% CI, 0.39-0.88; P =.0097). The 12-month OS was 52% in the T-DXd arm vs 28.9% in the comparison group.

Compared with patients who received either irinotecan or paclitaxel, those in the T-DXd group had longer median progression-free survival (5.6 vs 3.5 months) and 53% decreased risk of progression (95% CI, 0.31-0.71; P =.0003). The T-DXd group also had a longer median duration of response (11.3 vs 3.9 months).

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“T-DXd demonstrated statistically significant and clinically meaningful improvements in ORR and OS compared with standard chemotherapy (paclitaxel or irinotecan) in patients with HER2+ advanced gastric of GEJ adenocarcinoma,” the authors wrote.

Grade 3 or high adverse events occurred more frequently in the T-DXd arm than in the comparison arm (85.6% vs 56.5%). The most common adverse events were decreased neutrophil count (51.2% vs 24.2%, respectively), anemia (37.6% vs 22.6%), and decreased white blood cell count (20.8% vs 11.3%).

Disclosures: Daiichi Sankyo Co., Ltd, provided research funding. For a complete list of disclosures please refer to the original study.

Read more of Cancer Therapy Advisor‘s coverage of the ASCO 2020 meeting by visiting the conference page.

Reference

Shitatra K, Bang YJ, Iwasa S, et al. Trastuzumab deruxtecan (T-DXd; DS-8201) in patients with HER2-positive advanced gastric or gastroesophageal junction (GEJ) adenocarcinoma: A randomized, phase II, multicenter, open-label study (DESTINY-Gastric01). Presented at: ASCO20 Virtual Scientific Program. J Clin Oncol. 2020;38(suppl):abstr 4513.