ENHERTU (fam-trastuzumab deruxtecan-nxki) Significantly Improved Tumor Response Rate and Overall Survival in HER2-positive Metastatic Gastric Cancer in Phase II DESTINY-Gastric01 Trial

Detailed results from the positive registrational, randomized controlled Phase II DESTINY-Gastric01 trial showed AstraZeneca and Daiichi Sankyo Company, Limited’s (Daiichi Sankyo) ENHERTU® (fam-trastuzumab deruxtecan-nxki) demonstrated a statistically significant and clinically meaningful improvement in objective response rate (ORR) and overall survival (OS), a key secondary endpoint, versus chemotherapy.

The trial evaluated patients with HER2-positive unresectable or metastatic gastric or gastroesophageal junction adenocarcinoma that had progressed following two or more treatment regimens including trastuzumab and chemotherapy.

Gastric cancer is the third leading cause of cancer mortality with a five-year survival rate of 5% for metastatic disease. Approximately one in five gastric cancers are considered HER2 positive.

The confirmed ORR, assessed by independent central review, was 42.9% with ENHERTU monotherapy (6.4mg/kg) compared to 12.5% with investigator’s choice of chemotherapy (paclitaxel or irinotecan). Ten complete responses (CRs) and 41 partial responses (PRs) were seen in patients treated with ENHERTU versus no CRs and seven PRs seen in patients treated with chemotherapy.

Patients treated with ENHERTU had a 41% reduction in the risk of death versus patients treated with chemotherapy (based on a hazard ratio [HR] of 0.59; 95% confidence interval [CI] 0.39-0.88; p=0.0097) at a pre-specified interim analysis. The median OS was 12.5 months versus 8.4 months with chemotherapy. The estimated OS rate at one year in the ENHERTU arm was 52.1% and 28.9% with the chemotherapy arm.

Kohei Shitara, Chief of Department of Gastrointestinal Oncology, National Cancer Center Hospital East, Chiba, Japan and principal investigator in the Phase II DESTINY-Gastric01 trial, said: “Once patients with HER2-positive metastatic gastric cancer progress following initial treatment with an anti-HER2 regimen, there are limited treatment options and no approved HER2-targeted therapies. Based upon the compelling results of the DESTINY-Gastric01 trial, ENHERTU has the potential to become a new standard of care for these patients.”

José Baselga, Executive Vice President, R&D Oncology, said: “In DESTINY-Gastric01, the response rate was more than three times higher with ENHERTU versus chemotherapy. Additionally, more than half of patients treated with ENHERTU were alive at one year compared to less than a third with chemotherapy. In addition to the impressive results we saw in HER2-positive metastatic breast cancer in DESTINY-Breast01, these results in gastric cancer may help further define the role of ENHERTU in transforming patient outcomes across multiple HER2-targetable cancers.”

Antoine Yver Executive Vice President and Global Head, Oncology Research and Development, Daiichi Sankyo, said: “ENHERTU is the first HER2-directed therapy to show an improvement in overall survival for patients with previously treated HER2-positive metastatic gastric cancer. These data are encouraging and meaningful since patients with advanced gastric cancer have limited therapeutic options once they progress and face markedly high mortality rates. We are working with regulatory authorities to bring ENHERTU to patients with metastatic gastric cancer as quickly as possible.”

ENHERTUshowed a confirmed disease control rate (DCR) of 85.7% versus 62.5% and a median confirmed duration of response (DoR) of 11.3 months versus 3.9 months with chemotherapy.

Summary of results:i

The safety and tolerability profile of ENHERTU in DESTINY-Gastric01 was consistent with that observed in Phase I gastric cancer trial and previously reported ENHERTUtrials.The most common Grade 3 or higher treatment-emergent adverse events were decreased neutrophil count (51.2%), anemia (37.6%), decreased white blood cell count (20.8%) and decreased appetite (16.8%). There were 12 cases (9.6%) of confirmed treatment-related interstitial lung disease (ILD) and pneumonitis as determined by an independent review. The majority were Grade 1 or 2 with two Grade 3, one Grade 4, and no ILD-related deaths (Grade 5).

The results were presented during the 2020 American Society of Clinical Oncology (ASCO20) Virtual Scientific Program and simultaneously published online in the New England Journal of Medicine.

ENHERTU was recently granted Breakthrough Therapy Designation in the US for the treatment of patients with HER2-positive unresectable or metastatic gastric or gastroesophageal junction adenocarcinoma who have received two or more prior regimens including trastuzumab based on data from the DESTINY-Gastric01 trial and Orphan Drug Designation (ODD) for patients with gastric cancer, including gastroesophageal junction cancer.ENHERTU (5.4 mg/kg) is approved in the U.S. for the treatment of adult patients with unresectable or metastatic HER2 positive breast cancer who received two or more prior anti-HER2-based regimens based on the DESTINY-Breast01 trial. ENHERTU has not been approved in the United States for HER2-positive unresectable or metastatic gastric or gastroesophageal junction adenocarcinoma.

FDA-Approved Indication for ENHERTU

ENHERTU is a HER2-directed antibody and topoisomerase inhibitor conjugate indicated 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.

This indication is approved under accelerated approval based on tumor response rate and duration of response. Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial.

IMPORTANT SAFETY INFORMATION

Contraindications

None.

WARNINGS AND PRECAUTIONS

Interstitial Lung Disease / Pneumonitis

Severe, life-threatening, or fatal interstitial lung disease (ILD), including pneumonitis, can occur in patients treated with ENHERTU. In clinical studies, of the 234 patients with unresectable or metastatic HER2-positive breast cancer treated with ENHERTU, ILD occurred in 9% of patients. Fatal outcomes due to ILD and/or pneumonitis occurred in 2.6% of patients treated with ENHERTU. Median time to first onset was 4.1 months (range: 1.2 to 8.3).

Advise patients to immediately report cough, dyspnea, fever, and/or any new or worsening respiratory symptoms. Monitor patients for signs and symptoms of ILD. Promptly investigate evidence of ILD. Evaluate patients with suspected ILD by radiographic imaging. Consider consultation with a pulmonologist. For asymptomatic ILD/pneumonitis (Grade 1), interrupt ENHERTU until resolved to Grade 0, then if resolved in ≤28 days from date of onset, maintain dose. If resolved in >28 days from date of onset, reduce dose one level. Consider corticosteroid treatment as soon as ILD/pneumonitis is suspected (e.g., ≥0.5 mg/kg prednisolone or equivalent). For symptomatic ILD/pneumonitis (Grade 2 or greater), permanently discontinue ENHERTU. Promptly initiate corticosteroid treatment as soon as ILD/pneumonitis is suspected (e.g., ≥1 mg/kg prednisolone or equivalent). Upon improvement, follow by gradual taper (e.g., 4 weeks).

Neutropenia

Severe neutropenia, including febrile neutropenia, can occur in patients treated with ENHERTU. Of the 234 patients with unresectable or metastatic HER2-positive breast cancer who received ENHERTU, a decrease in neutrophil count was reported in 30% of patients and 16% had Grade 3 or 4 events. Median time to first onset was 1.4 months (range: 0.3 to 18.2). Febrile neutropenia was reported in 1.7% of patients.

Monitor complete blood counts prior to initiation of ENHERTU and prior to each dose, and as clinically indicated. Based on the severity of neutropenia, ENHERTU may require dose interruption or reduction. For Grade 3 neutropenia (Absolute Neutrophil Count [ANC] <1.0 to 0.5 x 109/L) interrupt ENHERTU until resolved to Grade 2 or less, then maintain dose. For Grade 4 neutropenia (ANC <0.5 x 109/L) interrupt ENHERTU until resolved to Grade 2 or less. Reduce dose by one level. For febrile neutropenia (ANC <1.0 x 109/L and temperature >38.3ºC or a sustained temperature of ≥38ºC for more than 1 hour), interrupt ENHERTU until resolved. Reduce dose by one level.

Left Ventricular Dysfunction

Patients treated with ENHERTU may be at increased risk of developing left ventricular dysfunction. Left ventricular ejection fraction (LVEF) decrease has been observed with anti-HER2 therapies, including ENHERTU. In the 234 patients with unresectable or metastatic HER2-positive breast cancer who received ENHERTU, two cases (0.9%) of asymptomatic LVEF decrease were reported. Treatment with ENHERTU has not been studied in patients with a history of clinically significant cardiac disease or LVEF <50% prior to initiation of treatment.

Assess LVEF prior to initiation of ENHERTU and at regular intervals during treatment as clinically indicated. Manage LVEF decrease through treatment interruption. Permanently discontinue ENHERTU if LVEF of <40% or absolute decrease from baseline of >20% is confirmed. When LVEF is >45% and absolute decrease from baseline is 10-20%, continue treatment with ENHERTU. When LVEF is 40-45% and absolute decrease from baseline is <10%, continue treatment with ENHERTU and repeat LVEF assessment within 3 weeks. When LVEF is 40-45% and absolute decrease from baseline is 10-20%, interrupt ENHERTU and repeat LVEF assessment within 3 weeks. If LVEF has not recovered to within 10% from baseline, permanently discontinue ENHERTU. If LVEF recovers to within 10% from baseline, resume treatment with ENHERTU at the same dose. When LVEF is <40% or absolute decrease from baseline is >20%, interrupt ENHERTU and repeat LVEF assessment within 3 weeks. If LVEF of <40% or absolute decrease from baseline of >20% is confirmed, permanently discontinue ENHERTU. Permanently discontinue ENHERTU in patients with symptomatic congestive heart failure.

Embryo-Fetal Toxicity

ENHERTU can cause fetal harm when administered to a pregnant woman. Advise patients of the potential risks to a fetus. Verify the pregnancy status of females of reproductive potential prior to the initiation of ENHERTU. Advise females of reproductive potential to use effective contraception during treatment and for at least 7 months following the last dose of ENHERTU. Advise male patients with female partners of reproductive potential to use effective contraception during treatment with ENHERTU and for at least 4 months after the last dose of ENHERTU.

Adverse Reactions

The safety of ENHERTU was evaluated in a pooled analysis of 234 patients with unresectable or metastatic HER2-positive breast cancer who received at least one dose of ENHERTU 5.4 mg/kg in DESTINY-Breast01 and Study DS8201-A-J101. ENHERTU was administered by intravenous infusion once every three weeks. The median duration of treatment was 7 months (range: 0.7 to 31).

Serious adverse reactions occurred in 20% of patients receiving ENHERTU. Serious adverse reactions in >1% of patients who received ENHERTU were interstitial lung disease, pneumonia, vomiting, nausea, cellulitis, hypokalemia, and intestinal obstruction. Fatalities due to adverse reactions occurred in 4.3% of patients including interstitial lung disease (2.6%), and the following events occurred in one patient each (0.4%): acute hepatic failure/acute kidney injury, general physical health deterioration, pneumonia, and hemorrhagic shock.

ENHERTU was permanently discontinued in 9% of patients, of which ILD accounted for 6%. Dose interruptions due to adverse reactions occurred in 33% of patients treated with ENHERTU. The most frequent adverse reactions (>2%) associated with dose interruption were neutropenia, anemia, thrombocytopenia, leukopenia, upper respiratory tract infection, fatigue, nausea, and ILD. Dose reductions occurred in 18% of patients treated with ENHERTU. The most frequent adverse reactions (>2%) associated with dose reduction were fatigue, nausea, and neutropenia.

The most common adverse reactions (frequency ≥20%) were nausea (79%), fatigue (59%), vomiting (47%), alopecia (46%), constipation (35%), decreased appetite (32%), anemia (31%), neutropenia (29%), diarrhea (29%), leukopenia (22%), cough (20%), and thrombocytopenia (20%).

Use in Specific Populations

• Pregnancy: ENHERTU can cause fetal harm when administered to a pregnant woman. Advise patients of the potential risks to a fetus. There are clinical considerations if ENHERTU is used in pregnant women, or if a patient becomes pregnant within 7 months following the last dose of ENHERTU.
• Lactation: There are no data regarding the presence of ENHERTU in human milk, the effects on the breastfed child, or the effects on milk production. Because of the potential for serious adverse reactions in a breastfed child, advise women not to breastfeed during treatment with ENHERTU and for 7 months after the last dose.
• Females and Males of Reproductive Potential: Pregnancy testing: Verify pregnancy status of females of reproductive potential prior to initiation of ENHERTU. Contraception: Females: ENHERTU can cause fetal harm when administered to a pregnant woman. Advise females of reproductive potential to use effective contraception during treatment with ENHERTU and for at least 7 months following the last dose. Males: Advise male patients with female partners of reproductive potential to use effective contraception during treatment with ENHERTU and for at least 4 months following the last dose. Infertility: ENHERTU may impair male reproductive function and fertility.
• Pediatric Use: Safety and effectiveness of ENHERTU have not been established in pediatric patients.
• Geriatric Use: Of the 234 patients with HER2-positive breast cancer treated with ENHERTU 5.4 mg/kg, 26% were ≥65 years and 5% were ≥75 years. No overall differences in efficacy were observed between patients ≥65 years of age compared to younger patients. There was a higher incidence of Grade 3-4 adverse reactions observed in patients aged ≥65 years (53%) as compared to younger patients (42%).
• Hepatic Impairment: In patients with moderate hepatic impairment, due to potentially increased exposure, closely monitor for increased toxicities related to the topoisomerase inhibitor.

To report SUSPECTED ADVERSE REACTIONS, contact Daiichi Sankyo, Inc. at 1-877-437-7763 or FDA at 1-800-FDA-1088 or fda.gov/medwatch.

Please see accompanying full Prescribing Information, including Boxed WARNING, and Medication Guide.

NOTES TO EDITORS

Gastric Cancer

Gastric (stomach) cancer is the fifth most common cancer worldwide and the third leading cause of cancer mortality with a five-year survival rate of 5% for metastatic disease; there were approximately one million new cases reported in 2018 and 783,000 deaths. In the US, it is estimated that 27,600 new cases of gastric cancer will be diagnosed in 2020 and more than 11,000 people will die from the disease.

Approximately one in five gastric cancers are HER2 positive. HER2 is a tyrosine kinase receptor growth-promoting protein expressed on the surface of many types of tumors including gastric, breast and lung cancers. Gastric cancer is usually diagnosed in the advanced stage, but even when diagnosed in earlier stages of the disease the survival rate remains modest. Recommended 1st-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. For gastric cancer that progresses on 1st-line treatment, there are no other approved HER2-targeted medicines.

DESTINY-Gastric01

DESTINY-Gastric01 is a registrational Phase II, open-label, randomized, multi-center trial testing the safety and efficacy of ENHERTU versus investigator’s choice chemotherapy in a primary cohort of 188 patients from Japan and South Korea with HER2-expressing, advanced gastric cancer or gastroesophageal junction adenocarcinoma (defined as IHC3+ or IHC2+/ISH+) who have progressed on two or more prior treatment regimens including fluoropyrimidine (5-FU) and platinum chemotherapy and trastuzumab. Patients were randomized 2:1 to receive ENHERTUor investigator’s choice of chemotherapy (paclitaxel or irinotecan monotherapy). Patients were treated with ENHERTU 6.4mg/kg once every three weeks or chemotherapy. The primary endpoint of the trial is ORR, as assessed by independent central review. ORR, or tumor response rate, represents the percentage of patients whose disease decreased and/or disappears. OS was a key secondary endpoint to be statistically evaluated hierarchically at a prespecified interim analysis if the primary endpoint was statistically significant. Other secondary endpoints include PFS, DoR, DCR and confirmed ORR assessed in those responses confirmed by a follow-up scan of at least 4 weeks after initial independent central review.

ENHERTU

ENHERTU (fam-trastuzumab deruxtecan-nxki in the US only) is a HER2-directed ADC and is the lead ADC in the oncology portfolio of Daiichi Sankyo and the most advanced program in AstraZeneca’s ADC scientific platform. ADCs are targeted cancer medicines that deliver cytotoxic chemotherapy (“payload”) to cancer cells via a linker attached to a monoclonal antibody that binds to a specific target expressed on cancer cells.

ENHERTUClinical Development

A comprehensive development program is underway globally with six registrational trials evaluating the efficacy and safety of ENHERTU monotherapy across multiple HER2-driven cancers including breast, gastric and lung cancers. Trials in combination with other anticancer treatments, such as immunotherapy, are also underway.

Collaboration between AstraZeneca and Daiichi Sankyo

In March 2019, AstraZeneca and Daiichi Sankyo entered into a global collaboration to jointly develop and commercialize ENHERTUworldwide, except in Japan where Daiichi Sankyo maintains exclusive rights. Daiichi Sankyo is solely responsible for manufacturing and supply.

About AstraZeneca in Oncology

AstraZeneca has a deep-rooted heritage in Oncology and offers a quickly-growing portfolio of new medicines that has the potential to transform patients’ lives and the Company’s future. With at least six new medicines to be launched between 2014 and 2020, and a broad pipeline of small molecules and biologics in development, we are committed to advance Oncology as a key growth driver for AstraZeneca focused on lung, ovarian, breast and blood cancers. In addition to our core capabilities, we actively pursue innovative partnerships and investments that accelerate the delivery of our strategy, as illustrated by our investment in Acerta Pharma in hematology.

By harnessing the power of four scientific platforms – Immuno-Oncology, Tumor Drivers and Resistance, DNA Damage Response and Antibody Drug Conjugates – and by championing the development of personalized combinations, AstraZeneca has the vision to redefine cancer treatment and one day eliminate cancer as a cause of death.

About AstraZeneca

AstraZeneca is a global, science-led biopharmaceutical company that focuses on the discovery, development and commercialization of prescription medicines, primarily for the treatment of diseases in three main therapy areas - Oncology, Cardiovascular, Renal & Metabolism and Respiratory and Immunology. The Company also is selectively active in the areas of autoimmunity, neuroscience and infection. AstraZeneca operates in over 100 countries and its innovative medicines are used by millions of patients worldwide. For more information, please visit www.astrazeneca-us.com and follow us on Twitter @AstraZenecaUS.

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