Dr Pothuri on Preliminary Data With Trastuzumab Pamirtecan in HER2-Expressing Endometrial Cancer

“Having an objective response rate of close to 50% is clearly tremendous, with a duration of response of 9.9 months. Seeing these durable responses that last is really important.”

Bhavana Pothuri, MD, professor in the Department of Obstetrics and Gynecology at NYU Grossman School of Medicine, professor in the Department of Medicine at NYU Grossman School of Medicine, director of Gynecologic Oncology Research, medical director of the Clinical Trials Office at Perlmutter Cancer Center, and director of Gynecologic Oncology Clinical Trials at NYU Langone Health, discussed early efficacy and safety findings from a global phase 2 study (NCT05150691) evaluating trastuzumab pamirtecan (DB-1303/BNT323) in patients with previously treated HER2-expressing advanced or metastatic endometrial cancer.

Trastuzumab pamirtecan is a novel HER2-directed antibody-drug conjugate (ADC) designed to deliver a potent cytotoxic payload directly to HER2-expressing tumor cells. In this heavily pretreated population, the agent demonstrated a compelling signal of clinical activity, with an objective response rate approaching 50%. This level of response is notable given the limited treatment options currently available for patients whose disease has progressed on prior therapies.

In addition to the depth of response, durability was also emphasized as a key outcome. The median duration of response was 9.9 months, suggesting that a meaningful proportion of patients experienced sustained clinical benefit. These findings highlight the potential of trastuzumab pamirtecan to provide not only tumor shrinkage but also prolonged disease control, Pothuri explained.

As with other agents in the ADC class, safety remains an important consideration. Overall, the treatment was described as well tolerated; however, Pothuri underscored the need for careful monitoring of interstitial lung disease (ILD). Early identification and proactive management of ILD are critical to minimizing the risk of more severe, higher-grade complications.

Taken together, these data support trastuzumab pamirtecan as a promising emerging option for patients with HER2-expressing endometrial cancer in the post-treatment setting. The combination of a high response rate and durable benefit is encouraging, although continued follow-up and further study will be essential to better characterize long-term outcomes and optimize safety management strategies.