Daiichi Sankyo and Merck have announced that their investigational drug Raludotatug Deruxtecan (R-DXd) has received Breakthrough Therapy Designation (BTD) from the US Food and Drug Administration (FDA). The designation is for the treatment of platinum-resistant epithelial ovarian, primary peritoneal, or fallopian tube cancers expressing the protein CDH6, in patients previously treated with Bevacizumab.

This is the first BTD granted for Raludotatug Deruxtecan, the second for the Daiichi Sankyo-Merck partnership and the 15th across Daiichi Sankyo’s oncology portfolio, marking a significant milestone in the companies’ joint efforts to develop innovative cancer therapies.

Raludotatug Deruxtecan is a potential first-in-class Antibody-Drug Conjugate (ADC) that targets CDH6—a protein overexpressed in around 65 percent of ovarian cancers. Developed using Daiichi Sankyo’s proprietary DXd technology, the ADC is designed to selectively deliver chemotherapy directly to cancer cells, improving efficacy while limiting damage to healthy tissue.

The FDA’s decision to grant BTD was based on promising data from an ongoing Phase-I trial and the REJOICE-Ovarian01 Phase-II/III trial, both of which have demonstrated early signs of clinical benefit in patients with limited treatment options. Results from subgroup analyses have been presented at multiple international oncology conferences, including ESMO and the Society for Gynecologic Oncology Annual Meeting.

“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 outcomes. The receipt of BTD 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.

REJOICE-Ovarian01 is a global, multi-centre Phase-II/III trial evaluating Raludotatug Deruxtecan in patients with platinum-resistant high-grade ovarian, primary peritoneal or fallopian tube cancers. The trial is enrolling approximately 710 patients worldwide and compares R-DXd with physician’s choice of standard chemotherapy. Key endpoints include Objective Response Rate (ORR) and Progression-Free Survival (PFS).

“The FDA’s Breakthrough Designation is a reflection of our commitment to advance 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.