Contrary to its role in lung cancer, PD-L1 expression does not predict benefit from immunotherapy in mesothelioma. Data from major trials shows similar outcomes regardless of PD-L1 status, leading clinicians to omit this test entirely and streamline treatment decisions.

Unlike immunotherapy, where re-challenge after progression is dubious, there is an emerging clinical practice of re-challenging patients with the same antibody-drug conjugate (ADC), such as enfortumab vedotin (EV), after a treatment break forced by toxicity. Anecdotally, patients are showing great responses, highlighting a key area for prospective data generation.

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.

Upcoming data for the HER2-ADC Disitamab Vedotin will test if its efficacy is enriched in HER2-high patients. This trial spotlights a key field-wide dilemma: is specific enrichment necessary, or does a "bystander effect," as seen in breast cancer, mean even low HER2 expression is enough, complicating patient selection and the drug's positioning.

For rashes caused by enfortumab vedotin (EV), dupilumab is an emerging steroid-sparing treatment. It can decrease the risk and severity of EV-related rashes, offering an alternative to corticosteroids, which some clinicians worry may blunt the efficacy of concurrent immunotherapy.

Unlike early ADCs requiring high biomarker expression (e.g., mirvetuximab), next-generation agents show efficacy even in low-expressing tumors. This allows for broader, "all-comer" clinical trial inclusion criteria instead of biomarker-gated entry, potentially expanding patient access to these novel therapies.

Unlike rare biomarkers that necessitate a 'test-and-wait' approach, IB6 is expressed in over 80-90% of NSCLC tumors. This ubiquity could make pre-screening unnecessary for drugs like Sigvotatug Vedotin, allowing clinicians to initiate targeted therapy much faster and for a broader patient population.

An individual tumor can have hundreds of unique mutations, making it impossible to predict treatment response from a single genetic marker. This molecular chaos necessitates functional tests that measure a drug's actual effect on the patient's cells to determine the best therapy.

Experts question the efficacy of sequencing ADCs like EV (Nectin-4 target) and DV (HER2 target) because they share the same MMAE chemo payload. Since resistance is often tied to the payload, not the target antibody, switching targets may not overcome resistance, though anecdotal responses have been observed.