FDA Grants Fast Track Designation to DB-1303 for Advanced HER2-Expressing Endometrial Cancer

The FDA has a granted fast track designation (FTD) to DB-1303 for the treatment of patients with advanced, recurrent, or metastatic endometrial carcinoma with HER2 overexpression, who have progressed on or after receiving standard systemic treatment.¹

There is a significant unmet need for treatments to address failure on previous platinum-based chemotherapy administered with or without immunotherapy in patients with advanced, recurrent, or metastatic endometrial carcinoma with HER2 overexpression, according to Duality Biologics, the developer of DB-1303.

DB-1303 is a novel antibody-drug conjugate comprised of anti-HER2 monoclonal antibody, enzymatically cleavable peptide-linker, and a proprietary topoisomerase I inhibitor, P1003. The safety, tolerability, and efficacy of the agent in being investigated in the phase 1/2a clinical trial (NCT05150691).

A total of 360 patients will be included in the multicenter, open-label, non-randomized trial of DB-1303. To enroll, patients must have pathologically documented HER2-positive or HER2-overexpressin advanced/unresectable, recurrent, or metastatic malignant solid tumors, at least 1 measurable lesion, an ECOG performance status of 01 or 1, adequate organ function, and a life expectancy of at least 3 months.²

Those with a history of symptomatic congestive heart failure or serious cardiac arrhythmia, myocardial infarction, or unstable angina within 6 months of day 1 of treatment are ineligible for the study. Patients are also excluded from the study if they have a history of significant lung disease or active infection or disease that may decrease the effectiveness of DB-1303. Patients cannot be hypersensitive for to any drub substance used in the study.

During the phase 1 portion of the study, investigators will assess dose-limiting toxicities, treatment-emergent adverse events (TRAEs), and serious AEs to determine the maximum-tolerated dose and the recommended phase 2 dose of DB-1303. During the phase 2a portion, investigators will assess the percentage of TRAEs, the percentage of serious AEs, and the objective response rate associated with DB-1303. The secondary end points of the study include pharmacokinetics, disease control rate, duration of response, time to response, time on therapy, and the percentage of change in target lesion from baseline to the final scan.

Study locations in the United States, Australia, and China are actively recruiting patients with HER2-expressing endometrial cancer, as well as those with breast cancer, gastric cancer, biliary tract cancer, and other advanced solid tumors that are HER2-low or HER2-positive.

"The FDA's decision to grant FTD underscores the potential for DB-1303 to address the unmet medical need and potentially serve as a new therapeutic option for patients with advanced, recurrent or metastatic endometrial carcinoma, said John Zhu, chief executive officer, DualityBio, in a press release. "We are committed to advance this investigational drug to help those patients who are suffering from cancers. We will work closely with clinical investigators and health authorities to unlock the full potential of DB-1303 in patients with malignant tumors."

_REFERENCES:

_{1. DualityBio announces DB-1303 granted fast track designation by the US food and drug administration (FDA) for the treatment of advanced, recurrent or metastatic endometrial carcinoma with HER2 overexpression. News release. January 20, 2023. Accessed January 20, 2023. https://prn.to/3R1NkIc}

_{2. A study of DB-1303 in advanced/metastatic solid tumors. ClinicalTrials.gov. Updated January 10, 2023. Accessed January 20, 2023. https://clinicaltrials.gov/ct2/show/NCT05150691}