(UroToday.com) The 2024 American Society of Clinical Oncology (ASCO) annual meeting featured a session on bladder cancer, and a presentation by Dr. Yijun Shen discussing results of a phase 2 trial of intravesical camrelizumab in BCG-unresponsive high-risk non-muscle invasive bladder cancer. In a phase I study, intravesical camrelizumab (at a maximum tolerated dose of 200 mg) was well tolerated by patients with BCG-unresponsive high-risk non-muscle invasive bladder cancer. This phase II trial aimed to assess the efficacy and safety of intravesical camrelizumab at the established phase I maximum tolerated dose.
Patients with histologically confirmed BCG-unresponsive high-risk non-muscle invasive bladder cancer, who were ineligible for or declined radical cystectomy, received intravesical camrelizumab at a dose of 200 mg every week for up to 6 weeks as the induction course. Subsequently, the maintenance therapy started with 200 mg administered every 3 weeks and continued until reaching the maximum treatment duration of 2 years or in the event of disease progression or unacceptable toxicity. The primary endpoint was the 3-month event free survival rate. The secondary endpoints included 6-month event free survival rate, 1-year event free survival rate, recurrence free survival, progression free survival, and safety. Biomarker exploration included PD-L1 expression and protein sequencing.
Between June 2021 and December 2023, 14 patients were enrolled and received at least one dose of camrelizumab, all of whom were included in the safety analysis. The baseline characteristics are as follows:
At a median follow-up of 23.1 months (IQR 15.8-28.6), the median event free survival was 12.68 months (95% CI 6.31-NE), with a 3-month event free survival rate of 92.3% (95% CI 77.8-100), a 6-month event free survival rate of 75.5% (95% CI 51.4-99.7), and a 12-month event free survival rate of 50.3% (95% CI 22.1-78.6). Both median recurrence free survival and progression free survival was 12.68 months (95% CI 6.31-NE).
Grade 1-2 treatment-emergent adverse events occurred in 2 (14.3%) patients, one with urinary tract infection and the other with vertebrobasilar insufficiency. Serious treatment-emergent adverse events occurred in one (7.1%) patient, and no deaths were reported:
PD-L1 expression was not related to treatment efficacy. Protein sequencing revealed a total of 296 proteins with differential expression between responsive and unresponsive patients. Analysis using Gene Ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathway demonstrated that the responsive group was associated with activated biological processes, including T cell receptor signaling pathway, alpha-beta T cell activation, and adaptive immune response:
Dr. Shen concluded his presentation discussing results of a phase 2 trial of intravesical camrelizumab in BCG-unresponsive high-risk non-muscle invasive bladder cancer with the following take home messages:
- Intravesical camrelizumab demonstrated promising anti-tumor activity and acceptable tolerance in patients with BCG-unresponsive non-muscle invasive bladder cancer who either declined or were ineligible for radical cystectomy
- This regimen shows promise as an effective non-surgical and topical treatment option for this specific population
- The efficacy was attributed to enhanced immune pathway activation
Presented by: Yijun Shen, Associate Professor, Fudan University Shanghai Cancer Center, Shanghai, China
Written by: Zachary Klaassen, MD, MSc – Urologic Oncologist, Associate Professor of Urology, Georgia Cancer Center, Wellstar MCG Health, @zklaassen_md on Twitter during the 2024 American Society of Clinical Oncology (ASCO) Annual Meeting, Chicago, IL, Fri, May 31 – Tues, June 4, 2024.