Bladder cancer that has spread is now often treated with a drug called enfortumab vedotin, given together with an immune therapy called pembrolizumab. This combination works well for many people, but about half stop responding within a year. Right now, doctors have no reliable way to know early on who will benefit.

Our study looked for clues in patients’ blood. We took blood samples before treatment started and again three weeks later, then compared the immune cells in people who responded to treatment with those who did not. We found clear differences between the two groups after just one round of treatment. This means a simple blood test may one day tell doctors within weeks, instead of months, whether a treatment is working.

That would matter a great deal to patients. These drugs can cause difficult side effects, including serious skin problems. Knowing early that a treatment is not helping would let patients stop it sooner and move on to something that might work better.

We are now studying tumor samples taken before treatment and again after the cancer returns, to understand why these treatments stop working and how to make them last longer.

Gupta, A., Sevilla, C., Pihlstrom, N. L., Liang, S., Regazzi, A. M., McCoy, A. S., Maher, C. A., Wong, P., Ahmed, F., Funt, S. A., Iyer, G., Bajorin, D. F., Teo, M. Y., Rosenberg, J. E., Osorio, J. C., & Aggen, D. H. (2025). Characterizing the immune effects of enfortumab vedotin (EV) on peripheral blood mononuclear cells (PBMCs) in metastatic urothelial cancer patients (mUC). Journal of Clinical Oncology, 43(5_suppl), 833–833. https://doi.org/10.1200/JCO.2025.43.5_suppl.833

Gupta, A., Sternschuss, M., Regazzi, A. M., Ahmed, F., Funt, S. A., Iyer, G., Rosenberg, J. E., Osorio, J. C., & Aggen, D. H. (2026). Characterizing the immune effects of enfortumab vedotin and pembrolizumab (EV+P) on peripheral blood mononuclear cells (PBMCs) in metastatic urothelial cancer patients (mUC). Journal of Clinical Oncology, 44(16_suppl), 4571–4571. https://doi.org/10.1200/JCO.2026.44.16_suppl.4571

None Reported as of August 2025

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