Case Report: HER2-Low Bladder Cancer With Liver Metastases Shows Deep Remission on ADC Plus Immunotherapy

A 73-year-old man with HER2-low metastatic urothelial carcinoma and multiple liver metastases achieved a near-complete resolution of his liver lesions after treatment with the HER2-targeted antibody-drug conjugate disitamab vedotin combined with the anti-PD-1 antibody toripalimab, according to a case report published in BMC Urology on 27 October 2026. The report, authored by Zhi-gang Chen, Ke-wei Tang and colleagues, is explicitly described by its authors as hypothesis-generating, since it involves a single patient and cannot establish which agent drove the response.

The patient first presented with painless gross hematuria lasting three days. Imaging and biopsy confirmed high-grade invasive urothelial carcinoma of the bladder with carcinoma in situ and glandular differentiation. He underwent laparoscopic radical cystectomy with lymph node dissection and ileal conduit diversion. Postoperative pathology showed high-grade invasive urothelial carcinoma with negative lymph nodes, high PD-L1 expression (immune cells greater than 1%, tumor cells 90%) and HER2 expression scored as 1+, placing him in the HER2-low category rather than the HER2-high disease covered by current treatment guidelines.

Five months after surgery, surveillance imaging revealed multifocal liver metastases. The patient declined first-line cisplatin chemotherapy, so his physicians instead started disitamab vedotin at 120 mg every two weeks together with toripalimab at 240 mg every three weeks. After two cycles of the combination, imaging showed a partial response with a 30% reduction in tumor burden. By eight cycles, the liver lesions had nearly resolved, corresponding to a 75% reduction measured by RECIST 1.1 criteria.

The regimen was generally tolerated. The patient developed transient grade 1 neuropathy, which was managed by extending the interval between antibody-drug conjugate doses to four weeks. Treatment was paused after twelve cycles, and at one-year follow-up the patient remained in sustained remission, according to the report.

The authors caution that the relative contribution of each drug remains unclear. Because the patient’s tumor showed high PD-L1 expression, that feature alone could explain part of the response to the immunotherapy component, independent of the HER2-targeted agent. Current guidelines focus on HER2-high disease, defined as IHC 3+ or 2+, whereas this patient’s tumor expressed HER2 at the 1+ level, making his response notable but not generalizable. The authors state that prospective validation is needed before the approach can be recommended more broadly, and the findings should be interpreted as an observation from one patient rather than evidence of treatment efficacy in the wider population.

Subject of Research: A case report of HER2-low metastatic urothelial carcinoma with liver metastases treated with an HER2-targeted antibody-drug conjugate plus an anti-PD-1 antibody.

Article Title: HER2-low metastatic urothelial carcinoma with liver metastases responding to antibody–drug conjugate therapy: a case report

Article References: Chen, Z.-G., Lu, X.-D., Lin, Y.-S., Li, B.-G., Tian, X.-J., & Tang, K.-W. (2026). HER2-low metastatic urothelial carcinoma with liver metastases responding to antibody–drug conjugate therapy: a case report. BMC Urology. https://doi.org/10.1186/s12894-026-02426-5

Image Credits: AI Generated

DOI: 10.1186/s12894-026-02426-5

Keywords: urothelial carcinoma, HER2-low, antibody-drug conjugate, disitamab vedotin, toripalimab, liver metastases, case report, immunotherapy, bladder cancer, RECIST, metastatic, urothelial