# Bladder preservation for MIBC after perioperative EV + pembrolizumab complete response

Source: https://onco.cc/ideas/idea-bladder-preservation-mibc/  
OnCo record `idea-bladder-preservation-mibc` (Idea). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

If the ADC-immunotherapy combination erases the tumour in more than half of patients before surgery, some may not need their bladder removed at all.

## Summary

pCR 57% in EV-303 and high pCR in EV-304 raise the question that dostarlimab answered in dMMR rectal cancer: can complete responders skip surgery? Trials (e.g., SunRISe-4 arms, MODERN, and investigator-led bladder-sparing studies) are beginning to test cystectomy omission with ctDNA and MRI-guided surveillance.

## Fields

- Kind: Idea
- Last checked: 2026-09-07
- Hypothesis: Patients with clinical complete response (cystoscopy, MRI, ctDNA-negative) after EV + pembrolizumab can defer cystectomy with a 2-year bladder-intact event-free survival above 70%.
- Rationale: Cystectomy carries major morbidity; response depth is now high enough that surveillance may be non-inferior for a selected group, as in rectal cancer organ preservation.
- Proposed test: Single-arm bladder-sparing trial with strict clinical complete response criteria and salvage cystectomy, compared against EV-303/304 outcomes; ctDNA (Signatera-type) as an eligibility and monitoring tool.
- Maturity: early-clinical

## Sources

- ClinicalTrials.gov NCT03924895: EV-303 / KEYNOTE-905: https://clinicaltrials.gov/study/NCT03924895
- ClinicalTrials.gov NCT04700124: EV-304 / KEYNOTE-B15: https://clinicaltrials.gov/study/NCT04700124

## Connected records

- cancers: [Bladder & urothelial cancer](https://onco.cc/cancers/urothelial/)
- technologies: [MRD / molecular residual disease testing](https://onco.cc/technologies/mrd-testing/), [MRI](https://onco.cc/technologies/mri/)
- drugs: [Enfortumab vedotin](https://onco.cc/drugs/enfortumab-vedotin/), [Pembrolizumab](https://onco.cc/drugs/pembrolizumab/), [Signatera](https://onco.cc/drugs/signatera/)
- trials: [EV-303 / KEYNOTE-905](https://onco.cc/trials/ev-303/), [EV-304 / KEYNOTE-B15](https://onco.cc/trials/ev-304/)
- key papers: [EV-302: enfortumab vedotin plus pembrolizumab replaces chemotherapy as first treatment for advanced bladder cancer](https://onco.cc/key-papers/paper-ev-302-nejm-2024/), [First-line pembrolizumab in cisplatin-ineligible patients with locally advanced and unresectable or metastatic urothelial cancer (KEYNOTE-052): a multicentre, single-arm, phase 2 study](https://onco.cc/key-papers/paper-pembrolizumab-urothelial-lancet-oncol-2017/), [Pembrolizumab as Second-Line Therapy for Advanced Urothelial Carcinoma](https://onco.cc/key-papers/paper-pembrolizumab-urothelial-n-engl-j-med-2017/)
- bottlenecks: [Surgery and radiotherapy cure most, get least](https://onco.cc/bottlenecks/b-surgery-radiation-innovation/)

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