Lapatinib as first-line treatment for muscle-invasive urothelial carcinoma in dogs

Epidermal growth factor receptors 1 and 2 (EGFR and HER2) are frequently overexpressed in various malignancies. Lapatinib is a dual tyrosine kinase inhibitor that inhibits both EGFR and HER2. Although a phase III trial failed to show the survival benefits of lapatinib treatment after first-line chemotherapy in patients with EGFR/HER2-positive metastatic urothelial carcinoma, the efficacy of lapatinib for untreated urothelial carcinoma is not well defined. Here, we describe the therapeutic efficacy of lapatinib as a first-line treatment in a canine model of muscle-invasive urothelial carcinoma. In this non-randomized clinical trial, we compared 44 dogs with naturally occurring urothelial carcinoma who received lapatinib and piroxicam, with 42 age-, sex-, and tumor stage-matched dogs that received piroxicam alone. Compared to the dogs treated with piroxicam alone, those administered the lapatinib/piroxicam treatment had a greater reduction in the size of the primary tumor and improved survival. Exploratory analyses showed that HER2 overexpression was associated with response and survival in dogs treated with lapatinib. Our study suggests that lapatinib showed encouraging durable response rates, survival, and tolerability, supporting its therapeutic use for untreated advanced urothelial carcinoma in dogs. The use of lapatinib as a first-line treatment may be investigated further in human patients with urothelial carcinoma.

BoNT/A in the Urinary Bladder—More to the Story Than Silencing of Cholinergic Nerves

Botulinum neurotoxin (BoNT/A) is an FDA and NICE approved second-line treatment for overactive bladder (OAB) in patients either not responsive or intolerant to anti-cholinergic drugs. BoNT/A acts to weaken muscle contraction by blocking release of the neurotransmitter acetyl choline (ACh) at neuromuscular junctions. However, this biological activity does not easily explain all the observed effects in clinical and non-clinical studies. There are also conflicting reports of expression of the BoNT/A protein receptor, SV2, and intracellular target protein, SNAP-25, in the urothelium and bladder. This review presents the current evidence of BoNT/A’s effect on bladder sensation, potential mechanisms by which it might exert these effects and discusses recent advances in understanding the action of BoNT in bladder tissue.