Researchers at Fox Chase Cancer Center have presented interim findings from a clinical trial showing promise for treating muscle-invasive bladder cancer. The RETAIN-2 trial, building on the previous RETAIN-1 study, indicates that combining neoadjuvant chemotherapy with immunotherapy may be more effective than chemotherapy alone in eradicating cancer and preserving patients’ bladders.
“Our goal with RETAIN is to help our patients preserve their bladders, if possible, while effectively treating muscle-invasive bladder cancer. With this second trial, we are finding that adding neoadjuvant immunotherapy may help us better achieve these aims,” said an Associate Professor at Fox Chase. She presented the results at the 2025 American Society of Clinical Oncology (ASCO) Genitourinary Cancers Symposium.
Currently, standard treatment involves chemotherapy followed by cystectomy. The earlier RETAIN-1 trial explored whether certain indicators could identify patients who might keep their bladders post-neoadjuvant chemotherapy and remain cancer-free. Researchers divided patients into an active surveillance group and a treatment group to compare outcomes over two years.
Led by Ghatalia, RETAIN-2 paired neoadjuvant chemotherapy with nivolumab immunotherapy in a study involving 71 patients. “In the active surveillance patient group, who kept their bladder, we’ve seen less disease recurrence compared to the same group in RETAIN-1. However, these results are exploratory as the purpose of RETAIN-2 was not to make a comparison with RETAIN-1,” said Ghatalia.
Additionally, 40% of cystectomy patients showed no evidence of cancer compared to 15% in RETAIN-1. “This suggests that there is potential value in combining neoadjuvant chemotherapy with ddMVAC and immunotherapy for patients with bladder cancer regardless of whether they undergo active surveillance or cystectomy,” Ghatalia added.
Although not all participants have reached the endpoint of metastasis-free survival after two years, 85% of the treatment group and 82% of the active surveillance group remain metastasis-free so far. Moreover, 60% of those under active surveillance retained their bladders during the study period.
The study titled “A Phase 2 Trial of Risk Enabled Therapy After Neoadjuvant Chemo-Immunotherapy for Muscle-Invasive Bladder Cancer (RETAIN-2)” was presented at ASCO’s symposium held in San Francisco from February 13-15.
