Daiichi Sankyo & Merck’s Raludotatug Deruxtecan (R-DXd) Receives FDA Breakthrough Therapy Designation For Platinum-Resistant Ovarian Cancer

Raludotatug deruxtecan (R-DXd), an investigational CDH6-directed antibody-drug conjugate (ADC) from Daiichi Sankyo and Merck (MSD outside the U.S. and Canada), has received Breakthrough Therapy Designation (BTD) from the U.S. Food and Drug Administration (FDA) for the treatment of adult patients with platinum-resistant epithelial ovarian, primary peritoneal, or fallopian tube cancers expressing CDH6, who have previously been treated with bevacizumab.

“Patients have limited treatment options once ovarian cancer becomes resistant to platinum-based chemotherapy, highlighting the urgent need for new medicines that can improve patient outcome. The receipt of Breakthrough Therapy Designation represents an important step forward in our efforts to advance raludotatug deruxtecan as a novel medicine for patients with CDH6 expressing platinum-resistant ovarian, primary peritoneal, or fallopian tube cancers previously treated with bevacizumab,” said Ken Takeshita, MD, Global Head, R&D, Daiichi Sankyo. 

R-DXd is a potential first-in-class therapy designed using Daiichi Sankyo’s proprietary DXd ADC technology platform. The FDA’s Breakthrough Therapy program is intended to expedite the development and review of therapies that target serious conditions with high unmet medical need and that have demonstrated encouraging preliminary clinical results showing meaningful advantages over existing therapies.

“The FDA’s Breakthrough Designation is a reflection of our commitment to advancing research for patients impacted by women’s cancers. Raludotatug deruxtecan has the potential to one day become an important option for the treatment of patients with CDH6-expressing platinum-resistant ovarian, primary peritoneal, or fallopian tube cancers previously treated with bevacizumab, and we are excited to share data from REJOICE-Ovarian01 with the scientific community at an upcoming medical meeting and to continue working closely with the FDA,” said Eliav Barr, MD, Senior Vice President, Head of Global Clinical Development and Chief Medical Officer, Merck Research Laboratories. 

The designation was supported by findings from an early-phase clinical study and the ongoing REJOICE-Ovarian01 phase 2/3 trial. Subgroup analyses from the phase 1 study have been highlighted at leading oncology congresses, including ESMO 2023, SGO 2024, and ESMO Gynaecological Cancers Congress 2025. This is the first Breakthrough Therapy Designation for R-DXd and the second achieved through the Daiichi Sankyo–Merck ADC collaboration, underscoring the partners’ progress in advancing novel ADCs in oncology.