Fox Chase Finds Year-Long Treatment-Free Intervals After Enfortumab Vedotin Is Stopped for Toxicity or Response

Seventy-three stops out of 147 charts

The design is a retrospective chart review, and treatment re-initiation and death were both modeled as competing risks, through cumulative incidence functions and Fine-Gray regression, which keeps a patient who dies during the break from being counted as a durable remission. The eight-week floor for calling something a treatment-free interval also excludes the ordinary dose holds that fill an enfortumab vedotin treatment record. Joy Li is first author and Pooja Ghatalia senior author, with Elizabeth R. Plimack, Daniel M. Geynisman, Matthew R. Zibelman and Fern Anari among the co-authors, all at the same Philadelphia institution.

Exposure length did not predict the interval

Both hazard ratios for duration of enfortumab vedotin came back flat, 1.02 with P = .78 for the single agent and 0.88 with P = .18 for the combination. A patient who tolerated twelve cycles was no more likely to hold a long break than one who stopped at four. What did separate the curves was depth of response, and the effect was substantial enough to reach significance in a subgroup of 73.

The pembrolizumab asterisk on 68.9%

The gap between 41.9% and 68.9% will get quoted, and the authors flag the reason it cannot be read as a straight comparison of two drug strategies. Patients on the combination were permitted to continue pembrolizumab after stopping the conjugate. Their treatment-free interval, as defined here, is an interval free of new systemic therapy, and for some of them checkpoint blockade was still running. Whether the higher figure reflects immunotherapy maintenance, a different response profile, or selection of a fitter first-line population is not something a 73-patient retrospective can separate.

PADCEV's label names the toxicities the abstract does not

The structured abstract groups toxicity and response together as reasons for discontinuation and never breaks the toxicity category into specific events. With the full text sold by subscription, how many stops were neuropathy and how many were skin cannot be said here. The prescribing information indicates which events are most likely to force a stop. PADCEV carries a boxed warning for severe and fatal cutaneous adverse reactions including Stevens-Johnson syndrome and toxic epidermal necrolysis, most often during the first cycle, and peripheral neuropathy appears in warnings and precautions with instructions to consider interruption, reduction or discontinuation, alongside hyperglycemia, pneumonitis and ocular disorders. The authors' own keyword list, which runs treatment breaks, treatment rechallenge and treatment-related adverse events, shows where they think the practical interest lies.

Why This Matters to the APO|APE Reader

Enfortumab vedotin is no longer confined to the metastatic setting the label first gave it: the current prescribing information covers neoadjuvant use with pembrolizumab in muscle-invasive bladder cancer, continued after cystectomy as adjuvant treatment. Every question this Philadelphia review raises about when to stop a Nectin-4 conjugate gets harder in a curative-intent population, where a neuropathy-driven stop is a decision about a patient who may already be cured. The 21.7% partial response rate on rechallenge is the number to carry into that conversation, because it is the first real-world estimate of what a second run at the drug is worth, and it comes from 23 patients at one center.