ENHERTU® (fam-trastuzumab deruxtecan-nxki) demonstrated a median progression-free survival of 13.2 months in HR-positive, HER2-low and HER2-ultralow metastatic breast cancer following one or more lines of endocrine therapy

DESTINY-Breast06 results show AstraZeneca and Daiichi Sankyo’s ENHERTU is the first HER2-directed medicine and ADC to demonstrate clinically meaningful benefit for patients in this setting

Additionally, data from DESTINY-Breast03 and DESTINY-Breast07 trials in HER2-positive metastatic breast cancer reinforce ENHERTU as standard of care in 2nd-line setting and highlight potential in 1st-line setting

WILMINGTON, Del.–(BUSINESS WIRE)–Detailed positive results from the DESTINY-Breast06 Phase III trial showed that ENHERTU^® (fam-trastuzumab deruxtecan-nxki) demonstrated a statistically significant and clinically meaningful improvement in progression-free survival (PFS) compared to standard-of-care chemotherapy in patients with HR-positive, HER2-low (IHC 1+ or 2+/ISH-) metastatic breast cancer and the overall trial population (patients with HR-positive, HER2-low and HER2-ultralow [defined as IHC 0 with membrane staining] expression) following one or more lines of endocrine therapy.

These results will be presented today as a late-breaking oral presentation during the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting (abstract #LBA1000).

ENHERTU is a specifically engineered HER2-directed DXd antibody drug conjugate (ADC) discovered by Daiichi Sankyo and being jointly developed and commercialized by AstraZeneca and Daiichi Sankyo.

In the primary analysis of DESTINY-Breast06, results showed ENHERTU reduced the risk of disease progression or death by 38% by blinded independent central review (BICR) versus chemotherapy in patients with HER2-low expression (hazard ratio [HR] 0.62; 95% confidence interval [CI]: 0.51-0.74; p<0.0001). Median PFS was 13.2 months in the ENHERTU arm compared to 8.1 months for chemotherapy.

PFS results by BICR in the overall trial population were similar and showed ENHERTU achieved a 37% reduction in the risk of disease progression or death compared to chemotherapy, with a median PFS of 13.2 months with ENHERTU versus 8.1 months for chemotherapy (HR 0.63; 95% CI: 0.53-0.75; p<0.0001).

A prespecified exploratory analysis showed the clinically meaningful improvement in PFS was consistent between patients with HER2-low and HER2-ultralow expression. In patients with HER2-ultralow expression, ENHERTU reduced the risk of disease progression or death by 22% compared to chemotherapy with a median PFS of 13.2 months versus 8.3 months, respectively (HR 0.78; 95% CI: 0.50-1.21).

Giuseppe Curigliano, MD, PhD, Professor of Medical Oncology at the University of Milan and Head of the Division of Early Drug Development at the European Institute of Oncology, IRCCS, Italy and principal investigator for the trial, said: “Endocrine therapies are widely used early in the treatment of HR-positive metastatic breast cancer, but following one or more lines of treatment, patients often derive limited efficacy from further endocrine-based therapy. With a median progression-free survival of more than a year, the results from DESTINY-Breast06 show that ENHERTU could become a new standard of care for patients with HER2-low- and HER2-ultralow-expressing tumors following endocrine therapy in the metastatic setting.”

Susan Galbraith, Executive Vice President, Oncology R&D, AstraZeneca, said: “DESTINY-Breast06 represents another potential paradigm shift in how we treat patients across the spectrum of HR-positive metastatic breast cancer. The results reinforce the potential for ENHERTU to improve outcomes earlier in the treatment landscape and in a broader population of patients with HER2-expressing breast cancer who have never before been eligible for a HER2-directed therapy.”

Ken Takeshita, Global Head, R&D, Daiichi Sankyo, said: “ENHERTU continues to deliver pioneering results for a HER2-directed medicine across many different types of cancer. These latest results from DESTINY-Breast06 demonstrate clinically meaningful results with ENHERTU even in tumors with very low levels of HER2 expression, suggesting that it may have an important role in treating a wide range of HER2-expressing metastatic breast cancer.”

In patients with HER2-low expression, confirmed objective response rate (ORR) was 56.5% for ENHERTU versus 32.2% with chemotherapy. In the overall trial population, confirmed ORR was 57.3% for ENHERTU versus 31.2% with chemotherapy and in patients with HER2-ultralow expression the confirmed ORR was 61.8% versus 26.3%, respectively. Complete responses were seen in 13 patients from the ENHERTU arm, including nine patients with HER2-low expression. In the HER2-ultralow subgroup, four patients in the ENHERTU arm had complete responses. No complete responses were seen in the chemotherapy arm.

Summary of results: DESTINY-Breast06

Patients in the trial received a median of two prior lines of endocrine therapy in each treatment arm. In the overall trial population, 14.9% of patients (n=65) in the ENHERTU arm and 19.2% of patients (n=82) in the chemotherapy arm had received one prior line of endocrine therapy. No patients in the trial had received prior chemotherapy treatment in the metastatic setting. Median duration of follow-up was 18.2 months. As of the data cut-off of March 18, 2024, a total of 119 patients (14%) remained on treatment, 89 patients receiving ENHERTU and 30 receiving chemotherapy.

The safety profile of ENHERTU was consistent with previous breast cancer clinical trials with no new safety concerns identified. The most common Grade 3 or higher treatment-related treatment-emergent adverse events occurring in 5% or more of patients treated with ENHERTU were neutropenia (20.7%), leukopenia (6.9%) and anemia (5.8%). Interstitial lung disease (ILD)/pneumonitis, adjudicated as drug-related by an independent committee, occurred in 11.3% of patients treated with ENHERTU. The majority of ILD events were low Grade (Grade 1 [n=7; 1.6%]; Grade 2 [n=36; 8.3%]). There were three Grade 3 ILD events (0.7%), no Grade 4 events and three Grade 5 events (0.7%).

Additional ENHERTU data at ASCO

DESTINY-Breast03 updated results

Updated overall survival (OS) results from the DESTINY-Breast03 Phase III trial showed ENHERTU continued to demonstrate a clinically meaningful survival improvement over trastuzumab emtansine (T-DM1) after more than three years of follow up in patients with HER2-positive unresectable and/or metastatic breast cancer previously treated with trastuzumab.

Results showed median OS was 52.6 months in the ENHERTU arm compared to 42.7 months for T-DM1 (HR 0.73; 95% CI: 0.56-0.94).

The safety profile of ENHERTU continues to be generally manageable and no cumulative toxicities were observed with longer follow-up. Results will be presented during the 2024 ASCO Annual Meeting (abstract #1025).

DESTINY-Breast07 results

Interim results from the DESTINY-Breast07 Phase Ib/II trial of ENHERTU alone or in combination with other anticancer therapies as a 1st-line treatment for HER2-positive metastatic breast cancer demonstrated promising clinical activity for ENHERTU as a monotherapy (n=75) and in combination with pertuzumab (n=50). Results were presented as an oral presentation at the 2024 ASCO Annual Meeting (abstract #1009).

Results showed a confirmed ORR of 76.0% with ENHERTU and 84.0% with ENHERTU in combination with pertuzumab. The 12-month PFS rate was 80.8% with ENHERTU monotherapy and 89.4% with ENHERTU and pertuzumab.

The safety of ENHERTU as a monotherapy and in combination with pertuzumab was consistent with the known safety profiles of each therapy. ILD/pneumonitis was reported in seven patients (9.3%) in the ENHERTU monotherapy arm and seven patients (14.0%) in the combination arm. All ILD events were Grade 3 or lower.

These are the first data presented for ENHERTU as a 1st-line treatment in HER2-positive metastatic breast cancer. Analyses from the ongoing DESTINY-Breast09 Phase III trial will provide further insights regarding the efficacy and safety of ENHERTU in this HER2-positive patient population.

Important Safety Information

Indications

ENHERTU is a HER2-directed antibody and topoisomerase inhibitor conjugate indicated for the treatment of adult patients with:

• Unresectable or metastatic HER2-positive (IHC 3+ or ISH positive) breast cancer who have received a prior anti-HER2-based regimen either:
  • In the metastatic setting, or
  • In the neoadjuvant or adjuvant setting and have developed disease recurrence during or within six months of completing therapy

• Unresectable or metastatic HER2-low (IHC 1+ or IHC 2+/ISH-) breast cancer, as determined by an FDA-approved test, who have received a prior chemotherapy in the metastatic setting or developed disease recurrence during or within 6 months of completing adjuvant chemotherapy

• Unresectable or metastatic non-small cell lung cancer (NSCLC) whose tumors have activating HER2 (ERBB2) mutations, as detected by an FDA-approved test, and who have received a prior systemic therapy

  This indication is approved under accelerated approval based on objective 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.

• Locally advanced or metastatic HER2-positive (IHC 3+ or IHC 2+/ISH positive) gastric or gastroesophageal junction (GEJ) adenocarcinoma who have received a prior trastuzumab-based regimen

• Unresectable or metastatic HER2-positive (IHC3+) solid tumors who have received prior systemic treatment and have no satisfactory alternative treatment options

  This indication is approved under accelerated approval based on objective 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.

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. A higher incidence of Grade 1 and 2 ILD/pneumonitis has been observed in patients with moderate renal impairment. 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/day prednisolone or equivalent). For symptomatic ILD/pneumonitis (Grade 2 or greater), permanently discontinue ENHERTU. Promptly initiate systemic corticosteroid treatment as soon as ILD/pneumonitis is suspected (e.g., ≥1 mg/kg/day prednisolone or equivalent) and continue for at least 14 days followed by gradual taper for at least 4 weeks.

HER2-Positive or HER2-Low Metastatic Breast Cancer, HER2-Mutant NSCLC, and Solid Tumors (Including IHC 3+) (5.4 mg/kg)

In patients with metastatic breast cancer, HER2-mutant NSCLC, and other solid tumors treated with ENHERTU 5.4 mg/kg, ILD occurred in 12% of patients. Median time to first onset was 5.5 months (range: 0.9 to 31.5). Fatal outcomes due to ILD and/or pneumonitis occurred in 1.0% of patients treated with ENHERTU.

HER2-Positive Locally Advanced or Metastatic Gastric Cancer (6.4 mg/kg)

In patients with locally advanced or metastatic HER2-positive gastric or GEJ adenocarcinoma treated with ENHERTU 6.4 mg/kg, ILD occurred in 10% of patients. Median time to first onset was 2.8 months (range: 1.2 to 21).

Neutropenia

Severe neutropenia, including febrile neutropenia, can occur in patients treated with ENHERTU. Monitor complete blood counts prior to initiation of ENHERTU and prior to each dose, and as clinically indicated. 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, then reduce dose by one level. For febrile neutropenia (ANC <1.0 x 10⁹/L and temperature >38.3º C or a sustained temperature of ≥38º C for more than 1 hour), interrupt ENHERTU until resolved, then reduce dose by one level.

HER2-Positive or HER2-Low Metastatic Breast Cancer, HER2-Mutant NSCLC, and Solid Tumors (Including IHC 3+) (5.4 mg/kg)

In patients with metastatic breast cancer, HER2-mutant NSCLC, and other solid tumors treated with ENHERTU 5.4 mg/kg, a decrease in neutrophil count was reported in 63% of patients. Seventeen percent had Grade 3 or 4 decreased neutrophil count. Median time to first onset of decreased neutrophil count was 22 days (range: 2 to 939). Febrile neutropenia was reported in 1% of patients.

HER2-Positive Locally Advanced or Metastatic Gastric Cancer (6.4 mg/kg)

In patients with locally advanced or metastatic HER2-positive gastric or GEJ adenocarcinoma treated with ENHERTU 6.4 mg/kg, a decrease in neutrophil count was reported in 72% of patients. Fifty-one percent had Grade 3 or 4 decreased neutrophil count. Median time to first onset of decreased neutrophil count was 16 days (range: 4 to 187). Febrile neutropenia was reported in 4.8% of patients.

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. Assess LVEF prior to initiation of ENHERTU and at regular intervals during treatment as clinically indicated. Manage LVEF decrease through treatment interruption. 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. 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.

HER2-Positive or HER2-Low Metastatic Breast Cancer, HER2-Mutant NSCLC, and Solid Tumors (Including IHC 3+) (5.4 mg/kg)

In patients with metastatic breast cancer, HER2-mutant NSCLC, and other solid tumors treated with ENHERTU 5.4 mg/kg, LVEF decrease was reported in 3.8% of patients, of which 0.6% were Grade 3.

HER2-Positive Locally Advanced or Metastatic Gastric Cancer (6.4 mg/kg)

In patients with locally advanced or metastatic HER2-positive gastric or GEJ adenocarcinoma treated with ENHERTU 6.4 mg/kg, no clinical adverse events of heart failure were reported; however, on echocardiography, 8% were found to have asymptomatic Grade 2 decrease in LVEF.

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 7 months after the last dose of ENHERTU. Advise male patients with female partners of reproductive potential to use effective contraception during treatment with ENHERTU and for 4 months after the last dose of ENHERTU.

Additional Dose Modifications

Thrombocytopenia

For Grade 3 thrombocytopenia (platelets <50 to 25 x 10⁹/L) interrupt ENHERTU until resolved to Grade 1 or less, then maintain dose. For Grade 4 thrombocytopenia (platelets <25 x 10⁹/L) interrupt ENHERTU until resolved to Grade 1 or less, then reduce dose by one level.

Adverse Reactions

HER2-Positive and HER2-Low Metastatic Breast Cancer, HER2-Mutant NSCLC, and Solid Tumors (Including IHC 3+) (5.4 mg/kg)

The pooled safety population reflects exposure to ENHERTU 5.4 mg/kg intravenously every 3 weeks in 1799 patients in Study DS8201-A-J101 (NCT02564900), DESTINY-Breast01, DESTINY-Breast02, DESTINY-Breast03, DESTINY-Breast04, DESTINY-Lung01, DESTINY-Lung02, DESTINY-CRC02, and DESTINY-PanTumor02. Among these patients, 65% were exposed for >6 months and 38% were exposed for >1 year. In this pooled safety population, the most common (≥20%) adverse reactions, including laboratory abnormalities, were nausea (73%), decreased white blood cell count (70%), decreased hemoglobin (66%), decreased neutrophil count (63%), decreased lymphocyte count (58%), fatigue (56%), decreased platelet count (48%), increased aspartate aminotransferase (47%), increased alanine aminotransferase (43%), vomiting (40%), increased blood alkaline phosphatase (38%), alopecia (34%), constipation (33%), decreased appetite (32%), decreased blood potassium (31%), diarrhea (29%), musculoskeletal pain (24%), and abdominal pain (20%).

HER2-Positive Metastatic Breast Cancer

DESTINY-Breast03

The safety of ENHERTU was evaluated in 257 patients with unresectable or metastatic HER2-positive breast cancer who received at least one dose of ENHERTU 5.4 mg/kg intravenously once every three weeks in DESTINY-Breast03. The median duration of treatment was 14 months (range: 0.7 to 30).

Serious adverse reactions occurred in 19% of patients receiving ENHERTU. Serious adverse reactions in >1% of patients who received ENHERTU were vomiting, interstitial lung disease, pneumonia, pyrexia, and urinary tract infection. Fatalities due to adverse reactions occurred in 0.8% of patients including COVID-19 and sudden death (one patient each).

ENHERTU was permanently discontinued in 14% of patients, of which ILD/pneumonitis accounted for 8%. Dose interruptions due to adverse reactions occurred in 44% of patients treated with ENHERTU. The most frequent adverse reactions (>2%) associated with dose interruption were neutropenia, leukopenia, anemia, thrombocytopenia, pneumonia, nausea, fatigue, and ILD/pneumonitis. Dose reductions occurred in 21% of patients treated with ENHERTU. The most frequent adverse reactions (>2%) associated with dose reduction were nausea, neutropenia, and fatigue.

The most common (≥20%) adverse reactions, including laboratory abnormalities, were nausea (76%), decreased white blood cell count (74%), decreased neutrophil count (70%), increased aspartate aminotransferase (67%), decreased hemoglobin (64%), decreased lymphocyte count (55%), increased alanine aminotransferase (53%), decreased platelet count (52%), fatigue (49%), vomiting (49%), increased blood alkaline phosphatase (49%), alopecia (37%), decreased blood potassium (35%), constipation (34%), musculoskeletal pain (31%), diarrhea (29%), decreased appetite (29%), headache (22%), respiratory infection (22%), abdominal pain (21%), increased blood bilirubin (20%), and stomatitis (20%).

HER2-Low Metastatic Breast Cancer

DESTINY-Breast04

The safety of ENHERTU was evaluated in 371 patients with unresectable or metastatic HER2-low (IHC 1+ or IHC 2+/ISH-) breast cancer who received ENHERTU 5.4 mg/kg intravenously once every 3 weeks in DESTINY-Breast04. The median duration of treatment was 8 months (range: 0.2 to 33) for patients who received ENHERTU.

Serious adverse reactions occurred in 28% of patients receiving ENHERTU. Serious adverse reactions in >1% of patients who received ENHERTU were ILD/pneumonitis, pneumonia, dyspnea, musculoskeletal pain, sepsis, anemia, febrile neutropenia, hypercalcemia, nausea, pyrexia, and vomiting. Fatalities due to adverse reactions occurred in 4% of patients including ILD/pneumonitis (3 patients); sepsis (2 patients); and ischemic colitis, disseminated intravascular coagulation, dyspnea, febrile neutropenia, general physical health deterioration, pleural effusion, and respiratory failure (1 patient each).

ENHERTU was permanently discontinued in 16% of patients, of which ILD/pneumonitis accounted for 8%. Dose interruptions due to adverse reactions occurred in 39% of patients treated with ENHERTU. The most frequent adverse reactions (>2%) associated with dose interruption were neutropenia, fatigue, anemia, leukopenia, COVID-19, ILD/pneumonitis, increased transaminases, and hyperbilirubinemia. Dose reductions occurred in 23% of patients treated with ENHERTU. The most frequent adverse reactions (>2%) associated with dose reduction were fatigue, nausea, thrombocytopenia, and neutropenia.

The most common (≥20%) adverse reactions, including laboratory abnormalities, were nausea (76%), decreased white blood cell count (70%), decreased hemoglobin (64%), decreased neutrophil count (64%), decreased lymphocyte count (55%), fatigue (54%), decreased platelet count (44%), alopecia (40%), vomiting (40%), increased aspartate aminotransferase (38%), increased alanine aminotransferase (36%), constipation (34%), increased blood alkaline phosphatase (34%), decreased appetite (32%), musculoskeletal pain (32%), diarrhea (27%), and decreased blood potassium (25%).

Contacts

Media Inquiries
Brendan McEvoy +1 302 885 2677

Jillian Gonzales +1 302 885 2677

US Media Mailbox: [email protected]

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