First Enhertu trial in Western patients with gastric cancer

Efficacy and safety results consistent with registrational DESTINY-Gastric01 will support ongoing discussions with global health authorities

Detailed results from the positive Phase II DESTINY-Gastric02 trial showed that Enhertu (trastuzumab deruxtecan), the AstraZeneca and Daiichi Sankyo Company, Limited (Daiichi Sankyo) HER2-directed antibody drug conjugate (ADC), provided a clinically meaningful and durable tumour response in patients with HER2-positive metastatic and/or unresectable gastric or gastroesophageal junction (GEJ) adenocarcinoma previously treated with a trastuzumab-containing regimen. Results were presented during a late-breaking mini-oral presentation at the European Society for Medical Oncology (ESMO) Congress 2021.

Gastric cancer is associated with a poor prognosis, particularly in the advanced stages of the disease, with only 5% to 10% of metastatic patients surviving five years globally.^1,2 Approximately one in five gastric cancers are HER2-positive.^3,4

In the primary analysis of DESTINY-Gastric02, the first trial of Enhertu specifically in Western patients with HER2-positive metastatic gastric cancer or GEJ adenocarcinoma, Enhertu (6.4 mg/kg) demonstrated a confirmed overall response rate (ORR) of 38% as assessed by independent central review (ICR). Three (3.8%) complete responses (CR) and 27 (34.2%) partial responses (PR) were observed in patients treated with Enhertu.

These results were consistent with those from the registrational DESTINY-Gastric01 Phase II trial previously published in The New England Journal of Medicine.

After a median follow-up of 5.7 months, the median duration of response (DoR) of Enhertu was 8.1 months (95% CI 4.1-NE). The median progression-free survival (PFS) was 5.5 months (95% CI 4.2-7.3). An exploratory endpoint of confirmed disease control rate (DCR) of 81% (95% CI; 70.6-89.0) was seen.

Eric Van Cutsem, MD, PhD, University Hospitals Leuven, said: “While the benefit of a HER2-targeted therapy in the first-line metastatic gastric cancer setting has been well-established, the disease will eventually progress. The positive results of DESTINY-Gastric02 show a strong response rate and reinforce the established efficacy and safety profile of Enhertu in patients who are in need of additional therapeutic options.”

Susan Galbraith, Executive Vice President, Oncology R&D, said: “The data from DESTINY-Gastric02 reaffirm the clinical significance of the potential benefit of Enhertu in patients with advanced gastric cancer. Patients often experience disease progression following initial therapies, and then face limited treatment options, so today’s news brings hope to both patients and treating physicians.”

Gilles Gallant, Senior Vice President, Global Head, Oncology Development, Daiichi Sankyo, said: “The encouraging results from DESTINY-Gastric02 are consistent with those previously seen in the pivotal DESTINY-Gastric01 trial. This additional data will support our ongoing discussions with global health authorities as we work toward Enhertu becoming an option for patients with HER2-positive metastatic gastric cancer.”

Summary of Results

ⁱ Enhertu 6.4 mg/kg; median duration of follow-up was 5.7 months.

ⁱⁱ As assessed by independent central review

ⁱⁱⁱ ORR is (CR + PR)

^iv DCR is (CR + PR +SD)

The overall safety profile of Enhertu in DESTINY-Gastric02 was consistent with that seen in DESTINY-Gastric01. The most common Grade 3 or higher drug-related treatment-emergent adverse events seen in DESTINY-Gastric02 were anaemia (7.6%), neutropenia (7.6%), nausea (3.8%) and fatigue (3.8%).

There were six cases (7.6%) of treatment-related interstitial lung disease (ILD) or pneumonitis reported, as determined by an independent adjudication committee. The majority (83%) were low Grade (Grade 1 or Grade 2), with one Grade 5 (ILD or pneumonitis-related death).

Enhertu is approved in Israel, Japan and the US for the treatment of adult patients with locally advanced or metastatic HER2-positive gastric or gastroesophageal junction adenocarcinoma who have received a prior trastuzumab-based regimen based on the results from the DESTINY-Gastric01 trial.

Enhertu is being further assessed in a comprehensive clinical development programme evaluating efficacy and safety across multiple HER2-targetable cancers, including breast, gastric, lung and colorectal cancers.

Several presentations featured during the ESMO Congress 2021 will showcase the strength and depth of Enhertu data across multiple tumour types, including gastric, lung and breast cancers, reinforcing the transformational potential of this medicine in the treatment of HER2-targetable cancers.

Gastric cancer

Gastric (stomach) cancer is the fifth most common cancer worldwide and the fourth highest leading cause of cancer mortality, with a five-year survival rate of 5% to 10% for advanced or metastatic disease.^1,5 There were approximately one million new cases of gastric cancer and 768,000 deaths reported worldwide in 2020.⁶

Incidence rates for gastric cancer are markedly higher in eastern Asia, where approximately half of all cases occur.^1,6,7 Gastric cancer is typically diagnosed in the advanced stage but even when diagnosed in earlier stages of the disease the survival rate remains modest.^8-10

Approximately one in five gastric cancers are HER2-positive.^3,4 HER2 is a tyrosine kinase receptor growth-promoting protein expressed on the surface of many types of tumours including breast, gastric, lung and colorectal cancers.⁴ HER2 overexpression may be associated with a specific HER2 gene alteration known as HER2 amplification.⁴

Recommended first-line treatment for HER2-positive advanced or metastatic gastric cancer is combination chemotherapy plus trastuzumab, an anti-HER2 medicine, which has been shown to improve survival outcomes when added to chemotherapy.⁷ For patients with metastatic gastric cancer that progresses following initial treatment with a trastuzumab-based regimen, treatment options are limited, and in many regions of the world, there are no additional HER2-directed medicines available.^1,8,11

DESTINY-Gastric02

DESTINY-Gastric02 is a global, open-label, single-arm, Phase II trial evaluating the safety and efficacy of Enhertu (6.4mg/kg) in patients with HER2-positive metastatic and/or unresectable gastric or GEJ adenocarcinoma with disease progression on or after a trastuzumab-containing regimen.

The primary endpoint of DESTINY-Gastric02 is objective response rate (ORR), confirmed by Independent Central Review (ICR). Secondary endpoints include progression-free survival (PFS) confirmed by ICR, investigator assessed PFS, investigator assessed ORR, overall survival (OS) and duration of response (DoR).

DESTINY-Gastric02 enrolled 79 patients at multiple sites in North America and Europe. For more information about the trial, visit ClinicalTrials.gov.

Enhertu

Enhertu is a HER2-directed ADC. Designed using Daiichi Sankyo’s proprietary DXd ADC technology, Enhertu is the lead ADC in the oncology portfolio of Daiichi Sankyo and the most advanced programme in AstraZeneca’s ADC scientific platform. Enhertu consists of a HER2 monoclonal antibody attached to a topoisomerase I inhibitor payload, an exatecan derivative, via a stable tetrapeptide-based cleavable linker.

Enhertu (5.4mg/kg) is approved in Canada, the EU, Israel, Japan, the UK and the US for the treatment of adult patients with unresectable or metastatic HER2-positive breast cancer who have received two or more prior anti-HER2-based regimens in the metastatic setting based on the results from the DESTINY-Breast01 trial.

Enhertu (6.4mg/kg) is also approved in Israel, Japan and the US for the treatment of adult patients with locally advanced or metastatic HER2-positive gastric or gastroesophageal junction adenocarcinoma who have received a prior trastuzumab-based regimen based on the results from the DESTINY-Gastric01 trial.

Enhertu development programme

A comprehensive development programme is underway globally, evaluating the efficacy and safety of Enhertu monotherapy across multiple HER2-targetable cancers, including breast, gastric, lung and colorectal cancers. Trials in combination with other anticancer treatments, such as immunotherapy, are also underway.

Enhertu was highlighted in the Clinical Cancer Advances 2021 report as one of two significant advancements in the “ASCO Clinical Advance of the Year: Molecular Profiling Driving Progress in GI Cancers,” based on data from both the DESTINY-CRC01 and DESTINY-Gastric01 trials, as well as one of the targeted therapy advances of the year in non-small cell lung cancer (NSCLC), based on the interim results of the HER2-mutated cohort of the DESTINY-Lung01 trial.

In May 2020, Enhertu also received Breakthrough Therapy Designation for the treatment of patients with metastatic NSCLC whose tumours have a HER2-mutation and with disease progression on or after platinum-based therapy.

Daiichi Sankyo collaboration

Daiichi Sankyo and AstraZeneca entered into a global collaboration to jointly develop and commercialise Enhertu (a HER2-directed ADC) in March 2019, and datopotamab deruxtecan (DS-1062; a TROP2-directed ADC) in July 2020, except in Japan where Daiichi Sankyo maintains exclusive rights. Daiichi Sankyo is responsible for manufacturing and supply of Enhertu and datopotamab deruxtecan.

AstraZeneca in gastrointestinal cancers

AstraZeneca has a broad development programme for the treatment of gastrointestinal (GI) cancers across several medicines spanning a variety of tumour types and stages of disease. In 2020, GI cancers collectively represented over five million new cancer cases leading to more than 3.5 million deaths.¹² Within this programme, the Company is committed to improving outcomes in gastric, liver, oesophageal, pancreatic, and colorectal cancers.

The Company aims to understand the potential of Enhertu in the two most common GI cancers, colorectal and gastric cancers. Imfinzi (durvalumab) is being assessed as both monotherapy and in combinations including with tremelimumab across the two main types of liver cancer, hepatocellular carcinoma and biliary tract cancer, and in oesophageal and gastric cancers.

Lynparza (olaparib) is a first-in-class PARP inhibitor with a broad and advanced clinical trial programme across multiple GI tumour types including pancreatic and colorectal cancers. Lynparza is development and commercialised in collaboration with MSD (Merck & Co., Inc. inside the US and Canada).

AstraZeneca in oncology

AstraZeneca is leading a revolution in oncology with the ambition to provide cures for cancer in every form, following the science to understand cancer and all its complexities to discover, develop and deliver life-changing medicines to patients.

The Company’s focus is on some of the most challenging cancers. It is through persistent innovation that AstraZeneca has built one of the most diverse portfolios and pipelines in the industry, with the potential to catalyse changes in the practice of medicine and transform the patient experience.

AstraZeneca has the vision to redefine cancer care and, one day, eliminate cancer as a cause of death.

AstraZeneca

AstraZeneca (LSE/STO/Nasdaq: AZN) is a global, science-led biopharmaceutical company that focuses on the discovery, development, and commercialisation of prescription medicines in Oncology, Rare Diseases, and BioPharmaceuticals, including Cardiovascular, Renal & Metabolism, and Respiratory & Immunology. Based in Cambridge, UK, AstraZeneca operates in over 100 countries and its innovative medicines are used by millions of patients worldwide. Please visit astrazeneca.com and follow the Company on Twitter @AstraZeneca.

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References

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https://www.cancerresearchuk.org/health-professional/cancer-statistics/statistics-by-cancer-type/stomach-cancer/survival. Accessed: September 2021.

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Accessed September 2021.