Japanese pharmaceutical company Daiichi Sankyo Company Limited (Tokyo:4568) and AstraZeneca Plc (STO:AZN) (LON:AZN), a pharmaceutical and medical products company, reported on Monday positive topline results from the pivotal phase 2 DESTINY-Gastric01 trial of DS-8201, a HER2 directed antibody drug conjugate (ADC), in patients with HER2 positive unresectable or metastatic gastric or gastroesophageal junction cancer that had progressed following two or more treatment regimens, including trastuzumab and chemotherapy.

Reportedly, the trial met its primary endpoint, achieving a statistically significant and clinically meaningful improvement in objective response rate (ORR), as assessed by an independent review committee, in patients treated with DS-8201 versus investigator's choice of chemotherapy (irinotecan or paclitaxel monotherapy).

Also, DS-8201 showed a statistically significant and clinically meaningful improvement in overall survival (OS), a key secondary endpoint. The safety profile observed for DS-8201 in DESTINY-Gastric01 was consistent with previous clinical trials.

These results confirm activity seen in the non-randomised phase 1 study of DS-8201 in patients with HER2 positive advanced gastric cancer published in The Lancet Oncology. Data from DESTINY-Gastric01 will be presented at an upcoming medical meeting.

Also, Daiichi Sankyo will initiate discussions with the Japan Ministry of Health, Labour and Welfare (MHLW) to determine next steps for a regulatory submission based on the results of DESTINY-Gastric01. Both companies also plan to discuss the data with other health authorities.

In March 2019, Daiichi Sankyo and AstraZeneca had entered into a global collaboration to jointly develop and commercialise DS-8201, except in Japan where Daiichi Sankyo maintains exclusive rights. Daiichi Sankyo is solely responsible for the manufacturing and supply.

A regulatory submission to the Japan MHLW for DS-8201 for the treatment of HER2 positive metastatic breast occurred in September 2019 and DS-8201 has previously received SAKIGAKE designation for the treatment of advanced HER2 positive gastric or gastroesophageal junction cancer by Japan's MHLW.