In real-world practice, oncologists are granting treatment breaks, or 'holidays,' to metastatic bladder cancer patients who achieve major responses on enfortumab vedotin-pembrolizumab. This practice, driven by toxicity management and quality of life concerns, is common despite the lack of formal trial data to guide the optimal duration or timing of discontinuation.

Contrary to concerns about tolerating Enfortumab Vedotin (EV) after major surgery, 80% of muscle-invasive bladder cancer patients who began the adjuvant phase in the KEYNOTE B15 trial successfully completed it. This suggests the regimen is more manageable post-cystectomy than anticipated.

In the EV+pembrolizumab combination, if a patient achieves an excellent response but develops prohibitive EV-related toxicities like neuropathy, a viable strategy is to discontinue EV and maintain the patient on pembrolizumab monotherapy. This can sustain the response while improving quality of life.

Extrapolating from the metastatic setting, clinicians should anticipate that most patients on the 9-cycle perioperative EV-pembrolizumab regimen will require dose reductions or holds. Cumulative peripheral neuropathy is the primary driver, suggesting a need for proactive, individualized dose management rather than strict adherence to the trial's protocol.

On-body glucose monitors give oncologists a richer understanding of a patient's glucose control, including 24-hour trends, time-in-range, and an A1c equivalent (GMI). This real-time data is critical for managing hyperglycemia from targeted therapies, offering more insight than periodic fasting tests.

The practice-changing Keynote B15 trial showed strong efficacy for neoadjuvant EV-Pembro. However, about half of patients discontinued treatment due to side effects. This creates a clinical paradox: patients who complete the full regimen may be over-treated, while those who stop early due to toxicity may be under-treated, complicating patient management and counseling.

Despite the perception that cisplatin-ineligible patients have worse disease biology, the pathologic complete response rates to neoadjuvant EV Pembro were nearly identical (56-57%) in both cis-ineligible (KEYNOTE-905) and cis-eligible (KEYNOTE-B15) trials. This suggests the regimen's high efficacy may overcome underlying biological differences.

The demonstrated superiority of the enfortumab vedotin (EV) and pembrolizumab combination over platinum chemotherapy has effectively made the Galski criteria, used for determining cisplatin eligibility, irrelevant. This marks a major paradigm shift in how frontline bladder cancer is approached, moving beyond platinum-based decisions.

New bladder-sparing trials mandate nine cycles of EV-Pembro to replicate the conditions of successful surgical trials. This conservative approach ignores that patient response is front-loaded while toxicity is back-loaded, likely overtreating many patients to ensure comparable efficacy.