Daiichi Sankyo introduces Enhertu - breast cancer drug in US

Tokyo and Basking Ridge, NJ – Daiichi Sankyo announced that ENHERTU® (fam-trastuzumab deruxtecan-nxki), a HER2 directed antibody-drug conjugate, is now available by prescription in the U.S.

ENHERTU was granted accelerated approval by the U.S. Food and Drug Administration (FDA) on December 20, 2019, 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.

“Many patients with this aggressive form of metastatic breast cancer continue to face tumor progression despite being treated with two or more HER2 directed treatment regimens,” said Ken Keller, President and CEO, Daiichi Sankyo, Inc. “We are proud that ENHERTU is now available in the U.S. nearly four months ahead of our original goal. Physicians now have a new specifically engineered HER2 directed antibody drug conjugate with demonstrated durable efficacy that may change the way these patients are treated.”

In the single-arm, phase 2 DESTINY-Breast01 trial that included 184 female patients with HER2 positive metastatic breast cancer, ENHERTU (5.4 mg/kg) achieved a confirmed objective response rate of 60.3% (n=111; 95% CI: 52.9-67.4), including a 4.3% complete response rate (n=8) and a 56.0% partial response rate (n=103).[1] The median duration of response was 14.8 months (n=111; 95% CI: 13.8-16.9).

ENHERTU is approved with a Boxed WARNING for Interstitial Lung Disease (ILD)/pneumonitis and Embryo-Fetal Toxicity. The safety of ENHERTU has been 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 the DESTINY-Breast01 trial and a phase 1 trial. ILD occurred in 9% of patients. Fatal outcomes due to ILD and/or pneumonitis occurred in six patients (2.6%) – two deaths already reported from the phase 1 trial and four deaths already reported in the phase 2 DESTINY-Breast01 trial.

Patients and physicians should be aware of ILD/pneumonitis and patients should be actively monitored for potential signs and symptoms. If ILD/pneumonitis is identified, it should be managed as per the FDA approved Prescribing Information. Management may require dose modification or treatment discontinuation and steroid treatment. ENHERTU can cause fetal harm when administered to a pregnant woman. The most common adverse reactions (frequency ≥20%) were nausea, fatigue, vomiting, alopecia, constipation, decreased appetite, anemia, neutropenia, diarrhea, leukopenia, cough and thrombocytopenia.