The photosensitivity reaction from loncastuximab tesirine can cause severe blistering. It's insufficient to only warn the patient. Clinicians must ensure that all caregivers, including family and facility staff, understand the need to keep the patient out of direct sunlight to prevent serious skin toxicity.

Due to fedratinib's significant GI side effect profile and the logistical difficulty of measuring thiamine levels, clinicians should proactively provide patients with thiamine supplements, anti-emetics, and anti-diarrheal therapies. Instructing patients to take the drug with food can also help mitigate GI toxicity.

Clinical trials with zanidatumab revealed significant diarrhea primarily in the first cycle. The successful management strategy involves mandatory loperamide twice daily for the first seven days to improve tolerability and prevent treatment discontinuation, a crucial implementation pearl.

Broad-spectrum RAS-on inhibitors like daraxonrasib present skin toxicity as a dose-limiting side effect. However, this rash is clinically distinct from that caused by EGFR inhibitors. It is often manageable with brief treatment interruptions, frequently without requiring dose reductions, and patients tend to acclimate to it over time.

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.

The RET inhibitor selpercatinib can cause a rare side effect of chylous (milky) ascites or pleural effusion. This can be misread on scans as cancer progression, leading to premature discontinuation of an effective drug. Clinicians must tap the fluid before assuming treatment failure, as switching to pralsetinib may resolve the issue.

When managing ocular toxicity from the ADC mirvetuximab, clinicians advocate for delaying the subsequent dose to allow the cornea to heal naturally. This approach is often preferred over an immediate dose reduction, which might unnecessarily compromise the treatment's efficacy.

When managing toxicities from trastuzumab deruxtecan (TDXD) in urothelial cancer, clinicians should refer to established protocols and literature from breast cancer, where experience is more extensive. This cross-disciplinary approach is necessary for managing side effects like nausea, vomiting, and lung disease until more bladder cancer-specific data becomes available.

To manage the significant diarrhea associated with the new drug zanidatumab, a proactive approach is critical. The successful HORIZON-GEA trial protocol included mandatory loperamide twice daily for the first seven days of cycle one, a strategy which effectively managed toxicity without leading to treatment discontinuation.