Aidixi Combination Therapy Improves Survival in Urothelial Carcinoma

Aidixi (disitamab vedotin) in combination with the PD-L1 inhibitor toripalimab reached its two primary end points of progression-free survival and overall survival compared with the standard chemotherapy as a first-line treatment in patients with HER2-expressing locally advanced or metastatic urothelial carcinoma, according to a news release from RemeGen.

In the phase 3 RC48-C016 trial, the combination of Aidixi and toripalimab significantly improved progression-free and overall survival versus chemotherapy, regardless of cisplatin eligibility or HER2 expression. The treatment also showed a manageable safety profile with tolerable side effects.

Full results on the study are planned to be presented at major international academic conferences later this year, and RemeGen plans to file biologic license application for this indication to the Center of Drug Evaluation of National Medical Products Administration (NMPA) in China.

Aidixi is the first domestically approved antibody-drug conjugate (ADC) in China. The drug targets HER2-expressing cancer cells by delivering a chemotherapy drug directly into them, disrupting cell division and causing cell death.

"Extremely exciting. We, once again, jointly witnessed a strong positive result of Aidixi combined with toripalimab in the first-line treatment of advanced urothelial carcinoma, Professor Guo Jun, the principal researcher of this study from Peking University Cancer Hospital, said in the news release. “Regardless of whether the patients are suitable for cisplatin treatment and regardless of patients' HER2 expression status, Aidixi combined with toripalimab significantly improved PFS and OS.”

Jun continues, “This outstanding efficacy proves the success of the 'HER2-ADC plus immunotherapy' combination treatment concept, and is also a major breakthrough in the global treatment of urothelial carcinoma. We look forward to the excellent performance of Aidixi in subsequent studies which should provide better decision-making basis for clinicians, bring more benefits to patients, and reshape the global treatment landscape of urothelial carcinoma with the 'Chinese approach'."

RC48-C016 is testing whether Aidixi plus toripalimab improves outcomes compared with standard chemotherapy in patients with previously untreated, HER2-expressing locally advanced or metastatic urothelial cancer. The study, which began in June 2022, enrolled 484 patients across 74 sites in China.

Aidixi’s Previous Indications of Efficacy in Bladder Cancer

In previous findings, according to results from a small study shared during the 2025 American Urological Association Annual Meeting, Aidixi showed encouraging activity when combined with Bacillus Calmette-Guérin (BCG) in patients with HER2-expressing, high-risk non–muscle-invasive bladder cancer who either had carcinoma in situ or were unable to undergo complete tumor resection. In addition, the clinical complete response was achieved in all 11 patients evaluable at three months and all five patients evaluable at six months. In three patients who had undergone complete tumor resection, event-free survival at six months was also 100%.

Treatment-related side effects occurred in 65% of patients and were generally manageable. These included elevated liver enzymes (40%), hair loss (45%), peripheral sensory neuropathy (35%), appetite loss (10%) and rash (5%). Side effects related to BCG were reported in 60% of patients and included bladder irritation, fever, joint pain, conjunctivitis and blood in the urine. Two patients experienced grade 3 (severe) side effects: one case of neuropathy related to Aidixi, and one case of hematuria related to BCG.

All patients received Aidixi at 2 milligrams per kilogram every three weeks for up to eight cycles, followed by one year of BCG bladder instillation. The main goals were to assess the three-month complete response rate in cohort A and the six-month event-free survival rate in cohort B.

Reference:

“Preliminary efficacy and safety of Aidixi (dv) combined with Bacillus Calmette-Guérin (BCG) in the treatment of high-risk non-muscle invasive bladder cancer with HER2 expression: a prospective, open label, single-center study,” by Dr. Shen Y, et al. J Urol.

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