A phase II study of RC48-ADC in HER2-negative patients with locally advanced or metastatic urothelial carcinoma.
Huayan Xu, Xinan Sheng, Xieqiao Yan, Zhihong Chi, Chuanliang Cui, Lu Si, Bixia Tang, Lili Mao, Bin Lian, Xuan Wang, Siming Li, Li Zhou, Xue Bai, Jun Guo
Abstract
e17113 Background: RC48-ADC is a novel humanized anti-HER2 antibody-drug conjugate (ADC). A phase II clinical study showed that RC48-ADC has a good effect on locally advanced or metastatic urothelial carcinoma with HER2-positive expression that failed standard chemotherapy. In the study, some patients with HER2-postive immunohistochemistry (IHC 2+) but negative FISH test still benefit from the treatment of RC48-ADC.The study was to evaluate the activity and safety of RC48-ADC in HER2-negative patients with locally advanced or metastatic urothelial carcinoma. Methods: This study is an open-label, single-center, one-arm, non-randomized phase II trial. Eligibility criteria include: histologically confirmed urothelial carcinoma, HER2-negasitive (IHC 0 or 1+), ECOG PS 0-1, treated with ≥1 prior systemic treatment. The patients received RC48-ADC treatment alone (2mg/kg IV infusion, q2w) until disease progression, unacceptable toxicity, withdrawal, or study termination. The primary objectives were activity (ORR) and safety. Progress-free survival, disease control rate and overall survival will also be assessed. Results: As of February 2020, 8 patients were enrolled in the study. The median age was 65 years old. At baseline, most patients (6/8) had visceral metastasis. 6 (75%) patients had received≥2 lines treatment and 4 (50%) patients had prior immune checkpoint inhibitor (CPI) therapy in second line treatment. The objective response rate was 25% (2/8) and the DCR was 75% (6/8). The ORR was 33.3% (2/6) in patients with visceral metastasis and was 50.0% (2/4) in liver metastasis patients. The ORR was 33.3% (2/6) in patients post to ≥ 2 lines of treatment and 25% (1/4) in patients post to immunotherapy. Common treatment-related AEs were AST increase (62.5%), ALT increase (50.0%), nausea (50.0%), leukopenia (37.5%), fatigue (37.5%), vomiting (37.5%), hypoesthesia (25.0%), alopecia (25.0%), and neutropenia (25.0%). Most of these AE were Grade 1 or 2. The AE of Grade 3 was neutropenia (12.5%). The SAE was CPK increased (12.5%). Conclusions: The study showed that RC48-ADC was safety and the ORR was 25% in HER-negative patients with locally advanced or metastatic urothelial carcinoma. Clinical trial information: NCT04073602.