犬の尿路上皮癌に対するラパチニブの皮膚有害事象が治療効果と関連する新たな指標となることを発見

2026-03-23

2026-03-20 東京大学

東京大学の研究グループは、犬の尿路上皮癌に対する分子標的薬ラパチニブ治療において、脱毛や痒みなどの皮膚有害事象が治療効果の指標となることを明らかにした。85頭の犬を対象に解析した結果、約3割で皮膚有害事象が発生し、これらが出現した症例では無増悪生存期間が有意に延長した。さらに多変量解析により、皮膚有害事象は独立した予後良好因子であることが示された。本研究は、犬の自然発症がんモデルを用いることで、分子標的薬の副作用と治療効果の関連を実証した初の成果であり、創薬研究への応用が期待される。

図1　皮膚有害事象の有無と無増悪生存期間との関連
皮膚有害事象を認めた症例(赤線)は認めなかった症例(黒線)よりも無増悪生存期間の延長がみられた。

＜関連情報＞

尿路上皮癌の犬におけるラパチニブ治療に関連する皮膚科的有害事象：後向き研究 Dermatological Adverse Events Associated With Lapatinib Treatment in Dogs With Urothelial Carcinoma: A Retrospective Study

Kosuke Horita, Tomohiro Yonezawa, Yasuyuki Momoi, Shingo Maeda
Veterinary Dermatology Published: 19 March 2026
DOI:https://doi.org/10.1111/vde.70062

ABSTRACT

Background

Lapatinib is widely used in human oncology; however, dermatological adverse events (DAEs) are common and have been correlated with treatment efficacy. In veterinary medicine, lapatinib use in combination with piroxicam has been shown to be effective in treating canine urothelial carcinoma (UC); however, the incidence and prognostic significance of DAEs in dogs remain unknown.

Objective

To evaluate the DAEs in dogs with UC treated with lapatinib and piroxicam.

Animals

Eighty-five dogs with UC were treated with lapatinib/piroxicam and 42 were treated with piroxicam alone.

Materials and Methods

This retrospective cohort study evaluated dogs diagnosed with UC and treated with lapatinib and piroxicam, and those treated with piroxicam alone. Relevant data were extracted from the medical records. The DAEs were assessed using the Veterinary Cooperative Oncology Group Common Terminology Criteria for Adverse Events and Naranjo algorithm. The log-rank test and Cox proportional hazards model were used to assess progression-free survival (PFS).

Results

DAEs occurred in 31.8% of the dogs in the lapatinib/piroxicam group, with alopecia and hyperpigmentation being the most common. In the piroxicam group, DAEs were observed in 7.1% of dogs. The relative risk of developing DAEs in the lapatinib/piroxicam group was 4.4 (p < 0.01). In the lapatinib/piroxicam group, DAEs were associated with a longer PFS (p < 0.03). The Cox proportional hazards model identified DAEs as independent prognostic factors for improved PFS (hazard ratio, 0.52, p < 0.05).