Merck And Daiichi Sankyo Launch Phase 3 Trial Of B7-H3 Targeting ADC For Metastatic Castration-Resistant Prostate Cancer (mCRPC)

Daiichi Sankyo and Merck have announced that the first patient has been dosed in the global Phase 3 IDeate-Prostate01 clinical trial, which is evaluating the investigational drug ifinatamab deruxtecan (I-DXd) against docetaxel in patients with metastatic castration-resistant prostate cancer (mCRPC). The trial focuses on patients whose disease has progressed following treatment with androgen receptor pathway inhibitors, aiming to assess the potential of I-DXd to become a new therapeutic option.

“Despite the emergence of new therapies, the current treatment landscape for patients with metastatic castration-resistant prostate cancer is challenging, and there is a need for new treatments. Following the promising results seen in our earlier phase trial, IDeate-Prostate01 has been initiated to evaluate whether ifinatamab deruxtecan may replace standard taxane-based chemotherapy as a potential treatment strategy in patients with metastatic castration-resistant prostate cancer with disease progression during or after treatment with androgen receptor pathway inhibitors,” said Mark Rutstein, MD, Head, Therapeutic Area Oncology Development, Daiichi Sankyo. 

Ifinatamab deruxtecan is a B7-H3–targeting antibody drug conjugate (ADC) developed by Daiichi Sankyo, and co-developed with Merck. B7-H3 is highly expressed in prostate tumors, making it a promising target for innovative treatment approaches. I-DXd leverages Daiichi Sankyo’s DXd ADC technology to selectively deliver chemotherapy directly to cancer cells, potentially offering a more effective and targeted treatment for mCRPC.

“IDeate-Prostate01 marks the initiation of the third pivotal trial in the ifinatamab deruxtecan development program and reinforces our commitment to addressing critical unmet needs for patients. Our continued progress in the exploration of this potential first-in-class B7-H3 antibody drug conjugate in collaboration with Daiichi Sankyo, speaks to our pursuit of novel science in the hopes of making a difference for patients in need of new options,” said Marjorie Green, MD, Senior Vice President and Head of Oncology, Global Clinical Development, Merck Research Laboratories. 

The need for new therapies is urgent, as metastatic prostate cancer has a markedly poor prognosis. While early-stage prostate cancer has a five-year survival rate above 90%, that figure drops to just 31% for advanced cases. Despite current treatments, many mCRPC patients fail to receive subsequent therapies due to toxicity, resistance, or limited options. This trial represents a pivotal step in exploring targeted, better-tolerated alternatives that may improve survival outcomes.