Skin adverse events may predict lapatinib benefit in dogs with UC

Lapatinib-linked skin changes may signal better outcomes in dogs with UC

A new retrospective study in Veterinary Dermatology suggests that dermatological adverse events during lapatinib treatment may be more than a tolerability issue in dogs with urothelial carcinoma. Investigators reviewed 85 dogs treated with lapatinib plus piroxicam and 42 treated with piroxicam alone, and found dogs receiving the lapatinib combination had a 4.4-fold higher risk of dermatological adverse events, including alopecia and hyperpigmentation. Those skin events were also associated with longer progression-free survival, supporting the idea that they may function as a treatment-response biomarker rather than simply an unwanted side effect. (researchgate.net)

Why it matters: For veterinary teams managing canine urothelial carcinoma, the finding adds nuance to adverse-event monitoring around a targeted therapy that has already shown clinical activity in this disease. Earlier clinical work found lapatinib plus piroxicam improved response and survival versus piroxicam alone in dogs with naturally occurring urothelial carcinoma, particularly in tumors with higher HER2 expression, while adverse events were generally manageable. The new study suggests at least some cutaneous changes may track with drug activity, echoing human oncology literature in which lapatinib is associated with increased risk of rash, pruritus, and other mucocutaneous effects. That could affect how clinicians counsel pet parents, document skin findings, and weigh dose adjustments when dermatologic toxicity emerges. (pubmed.ncbi.nlm.nih.gov)

What to watch: Prospective studies will be needed to confirm whether lapatinib-associated skin events can be used reliably as a clinical biomarker and to define when supportive care is preferable to dose reduction. (researchgate.net)