Sophia Kamran, MD, highlights key bladder cancer data from ASCO GU 2026

In the following video, Sophia C. Kamran, MD, highlights some of the key bladder cancer trials presented at the 2026 American Society of Clinical Oncology (ASCO) Genitourinary Cancers Symposium in San Francisco, California. Kamran is a radiation oncologist at the Massachusetts General Hospital and an associate professor of radiation oncology at Harvard Medical School in Boston, Massachusetts.

Specifically, Kamran touches on the following studies:

1. Circulating tumor DNA (ctDNA) to guide response-adapted bladder preservation in muscle invasive bladder cancer (MIBC): Integrated analysis of the RETAIN trials
2. Gemcitabine intravesical system (Gem-iDRS) in combination with cetrelimab (CET) versus chemoradiotherapy (CRT) in muscle-invasive bladder cancer (MIBC): SunRISe-2 final results
3. A phase II clinical trial of neoadjuvant sasanlimab and stereotactic body radiation therapy as an in situ vaccine for cisplatin-ineligible muscle invasive bladder cancer: The RAD VACCINE MIBC clinical trial

Kamran first highlighted findings from an integrated analysis from RETAIN-1 and RETAIN-2. These studies evaluated a risk-adapted strategy in muscle-invasive bladder cancer (MIBC), incorporating upfront systemic therapy followed by either active surveillance or bladder-directed therapy based on mutational status. An exploratory analysis examined circulating tumor DNA (ctDNA) as a biomarker of response. The findings demonstrated that ctDNA is a valuable tool for monitoring systemic disease and detecting distant metastases but is not reliable for assessing local tumor response within the bladder. Kamran noted that these results align with prior work from her group and collaborators, reinforcing that while ctDNA may help guide post-treatment surveillance for systemic recurrence, it cannot replace cystoscopy or other modalities for local evaluation. Future research may explore complementary biomarkers, such as urine tumor DNA, to better assess intravesical disease.

She next discussed the phase 3 SunRISe-2 trial, which evaluated an intravesical drug-delivery device (formerly TAR-200) administering gemcitabine in combination with a novel anti–PD-1 antibody for localized MIBC. This regimen was compared with standard chemoradiation for bladder preservation. The trial, which enrolled more than 500 patients, was discontinued at interim analysis after failing to demonstrate superior bladder-intact event-free survival compared with chemoradiation. Although the investigational combination showed favorable tolerability and safety, the results reaffirm chemoradiation as the standard of care for organ preservation in this setting. Kamran noted that the device continues to be studied in other disease contexts, including non–muscle-invasive bladder cancer and in neoadjuvant strategies prior to cystectomy.

Finally, Kamran highlighted the phase 2 RAD VACCINE MIBC study, which explored the combination of stereotactic body radiation therapy (SBRT) and immune checkpoint inhibition as neoadjuvant therapy for cisplatin-ineligible patients with MIBC undergoing cystectomy. In this small, hypothesis-generating trial of approximately 30 patients, the combination achieved a pathologic complete response rate of 44.8%, with acceptable toxicity. While preliminary, these findings suggest potential for this strategy in the neoadjuvant setting. Kamran emphasized that further investigation is needed to clarify how this approach compares with or complements emerging neoadjuvant regimens and whether it may also have a role in bladder-preservation strategies moving forward.

REFERENCES

1. Ghatalia P. Circulating tumor DNA (ctDNA) to guide response-adapted bladder preservation in muscle invasive bladder cancer (MIBC): Integrated analysis of the RETAIN trials. Presented at: 2026 American Society of Clinical Oncology Genitourinary Cancers Symposium. February 26-28, 2026. San Francisco, California. Abstract LBA632. https://www.asco.org/abstracts-presentations/256835

2. Necchi A. Gemcitabine intravesical system (Gem-iDRS) in combination with cetrelimab (CET) versus chemoradiotherapy (CRT) in muscle-invasive bladder cancer (MIBC): SunRISe-2 final results. Presented at: 2026 American Society of Clinical Oncology Genitourinary Cancers Symposium. February 26-28, 2026. San Francisco, California. Abstract 635. https://www.asco.org/abstracts-presentations/256842

3. A phase II clinical trial of neoadjuvant sasanlimab and stereotactic body radiation therapy as an in situ vaccine for cisplatin-ineligible muscle invasive bladder cancer: The RAD VACCINE MIBC clinical trial. Presented at: 2026 American Society of Clinical Oncology Genitourinary Cancers Symposium. February 26-28, 2026. San Francisco, California. Abstract 750. https://www.asco.org/abstracts-presentations/257009/abstract