AstraZeneca, Daiichi Sankyo’s Enhertu Meets Primary Endpoint of Progression-Free Survival

AstraZeneca and Daiichi Sankyo announced positive topline results from the DESTINYBreast02 (NCT03523585) phase 3 trial of trastuzumab deruxtecan (Enhertu) compared with the physician’s choice of treatment for individuals with HER2 positive unresectable and/or metastatic breast cancer who were previously treated with trastuzumab emtansine.

The trial met the primary endpoint of demonstrating a statistically significant and clinically meaningful improvement in progression free survival (PFS) and the key secondary endpoint of improved overall survival.

Other secondary endpoints include objective response rate based on blinded independent central review (BICR) and investigator assessment, duration of response based on BICR, PFS based on investigators assessment, and safety.

“The topline results from DESTINY-Breast02 confirm the robust [PFS] seen in previous trials of [trastuzumab deruxtecan] and enrich our clinical understanding of the benefit this therapy may offer patients with HER2 positive metastatic breast cancer,” Ken Takeshita, MD, global head of R&D at Daiichi Sankyo, said in a statement. “As this is the confirmatory trial for our current breast cancer indication in Europe and several other countries, we look forward to sharing these findings with regulatory authorities to add to the body of data for [trastuzumab deruxtecan] for the treatment of HER2 positive metastatic breast cancer.”

Trastuzumab deruxtecan is a specifically designed HER2-directed antibody drug conjugate being developed and commercialized by AstraZeneca and Daiichi Sankyo.

The DESTINY-Breast02 is a global, open-label, phase 3, randomized trial that evaluated the efficacy and safety of trastuzumab deruxtecan at the 5.4 mg/kg dosage with treatment of either lapatinib and capecitabine or trastuzumab and capecitabine.

Investigators evaluated a similar population as the single-arm DESTINY-BREAST01 (NCT03248492) phase 2 trial, which is the basis for initial approvals in advanced HER2 positive metastatic breast cancer, where the patients receive the treatment as a later line of therapy. Patients were randomized 2 to 1 and received either trastuzumab deruxtecan or the physician’s choice of treatment.

The trial included approximately 600 individuals at multiple sites in Asia, Europe, North America, Oceania, and South America.

The safety profile of trastuzumab deruxtecan was consistent with previous phase 3 clinical trials with no new safety signals identified.

The interstitial lung disease (ILD) rates and severity were generally consistent with those observed in other metastatic breast cancer trials of the drug. There was a low rate of grade 5 ILD observed and determined by an independent adjudication committee.

“The DESTINY-Breast02 trial results in this patient population with advanced disease confirm the efficacy and safety profile seen in DESTINY-Breast01 and are consistent with the results seen across our broader clinical program in HER2 positive metastatic breast cancer,” Susan Galbraith, MBBChir, PhD, executive vice president of Oncology R&D at AstraZeneca, said in the statement. “These data further strengthen our confidence in [trastuzumab deruxtecan] and reinforce its potential to transform patient outcomes across multiple treatment settings.”

The results will be presented at an upcoming medical meeting.

Reference

Enhertu significantly delayed disease progression in DESTINY-Breast02 phase 3 trial versus physician’s choice of treatment in patients with HER2 positive metastatic breast cancer. News release. Businesswire. August 15, 2022. Accessed August 15, 2022. https://www.businesswire.com/news/home/20220814005011/en