Study to assess performance of CxBladder test in urothelial carcinoma surveillance

The protocol for the observational LOBSTER study (NCT05080998), which is assessing the performance of the CxBladder Monitor and Monitor Plus tests in the surveillance for recurrence in patients with low-, intermediate-, and high-risk urothelial carcinoma, was shared during a presentation at the 100th annual meeting for the Western Section of the American Urological Association (WSAUA) in Kauai, Hawaii.¹

Of those currently enrolled, 46 have been confirmed to have tumors.

The multi-site, observational study has already enrolled 303 patients and collected 479 voided urine samples. Recruitment for the study remains ongoing. In total, the study plans to enroll 400 to 500 adult participants, with a goal of 75 confirmed tumors.

Among those currently enrolled in the study, 46 patients have been confirmed to have tumors. An interim analysis of the data will be conducted once 50 confirmed tumors have been identified.

Patients are eligible for enrollment in the study if they are under surveillance for non–muscle-invasive bladder cancer (NMIBC); have low-, intermediate-, or high-risk disease based on American Urological Association (AUA)/Society of Urologic Oncology guidelines; experienced previous recurrence of urothelial carcinoma; and are able to provide a voided urine sample.² Those with prior genitourinary manipulation, total cystectomy of the bladder, muscle-invasive bladder tumor, or who are currently pregnant are excluded from enrollment.

The trial is enrolling patients through Veterans Affairs and other medical centers across the United States.

For the study, patients will provide voided urine samples at the initial visit and at up to 3 successive surveillance cystoscopy visits over a 2-year follow-up period. Urine samples will be tested with the Monitor/Monitor+ tests and central urine cytology to assess for recurrence. CxBladder tests will be alternated with cystoscopy at consecutive visits to directly compare the proposed pathway to standard of care. Patients, physicians, and laboratory staff will be blinded to CxBladder results.

According to the investigators, “Primary tumor tissue will also be collected when available for genotyping using DNA markers to assess UC risk.”

The investigators added, “Through this study, a proposed clinical pathway utilizing the Monitor+ test would allow for Monitor+ negative patients to defer cystoscopy for this time point while Monitor+ positive patients would be recalled for immediate evaluation. This pathway would provide substantial reduction of the burden of surveillance for those patients.”¹

The primary end points for the study include sensitivity, specificity, negative predictive value, positive predictive value, and test-negative rate of the CxBladder tests.

According to the company, goals of the trial include demonstrating that it is safe to alternate CxBladder with cystoscopy for patients under surveillance for recurrence of urothelial carcinoma as well as providing support for the inclusion of biomarkers as an alternative to cystoscopy in this setting in the AUA/National Comprehensive Cancer Network guidelines.³

Final completion of the LOBSTER study is anticipated for 2025, with a target date of publication of the results in 2027.⁴

References

1. Wright JL, Schroek F, Ercole C, et al. An observational study of Cxbladder monitoring for recurrence of urothelial carcinoma in low, intermediate, and high-risk patients (LOBSTER). Presented at: 110th annual meeting for the Western Section of the American Urological Association (WSAUA). October 27-November 1, 2024. Kauai, Hawaii. Abstract 318

2. CxBladder surveillance of intermediate and high-risk bladder cancer patients. ClinicalTrials.gov. Last updated September 14, 2022. Accessed November 6, 2024. https://clinicaltrials.gov/study/NCT05080998

3. Clinical trials. Pacific Edge. Accessed November 6, 2024. https://www.pacificedgedx.com/company/clinical-trials/

4. Real world evidence for Cxbladder to feature at WSAUA. News release. Pacific Edge. October 24, 2024. Accessed November 6, 2024. https://www.pacificedgedx.com/news-and-events/news/2024/real-world-evidence-for-cxbladder-to-feature-at-wsaua/