Final Results of a Phase I Trial of WST-11 (TOOKAD Soluble) Vascular-targeted Photodynamic Therapy for Upper Tract Urothelial Carcinoma
Wesley Yip, Daniel D. Sjoberg, Lucas Nogueira, Andrew Tracey, Ricardo Alvim, Peter A. Reisz, Quinlan Demac, Nicole Benfante, Rand W. Vanden Berg, Kwanghee Kim, Hikmat Al‐Ahmadie, Oscar Lin, Bernard H. Bochner, Guido Dalbagni, S. Machele Donat, Eugene J. Pietzak, A. Ari Hakimi, David B. Solit, Avigdor Scherz, Dean F. Bajorin, Jonathan Coleman
Abstract
PURPOSE: Vascular-targeted photodynamic therapy with the intravascular photosensitizing agent padeliporfin (WST-11/TOOKAD-Soluble) has demonstrated therapeutic efficacy as an ablative treatment for localized cancer with potential adaptation for endoscopic management of upper tract urothelial carcinoma. This Phase I trial (NCT03617003) evaluated the safety of vascular-targeted photodynamic therapy with WST-11 in upper tract urothelial carcinoma. MATERIALS AND METHODS: Nineteen patients underwent up to 2 endoscopic vascular-targeted photodynamic therapy treatments, with follow-up for up to 6 months. Patients who had residual or recurrent upper tract urothelial carcinoma (any grade/size) failing prior endoscopic treatment or unable or unwilling to undergo surgical resection were eligible for inclusion. The primary endpoint was to identify the maximally tolerated dose of laser light fluence. A dose escalation model was employed, with increasing light fluence (100-200 mW/cm) using a modified continual reassessment method. The secondary endpoint was treatment efficacy, defined by absence of visible tumor and negative urine cytology 30 days posttreatment. RESULTS: Fourteen (74%) patients received the maximally tolerated dose of 200 mW/cm, 2 (11%) of whom experienced a dose-limiting toxicity. The initial 30-day treatment response rate was 94% (50% complete, 44% partial). Eight patients underwent a second treatment, with a final observed 68% complete response rate. Leading toxicities were flank pain (79%) and hematuria (84%), which were transient. No ureteral strictures associated with treatment were identified during follow-up. CONCLUSIONS: Vascular-targeted photodynamic therapy with WST-11 has an acceptable safety profile with strong potential as an effective, kidney-sparing endoscopic management option for upper tract urothelial carcinoma. The recently initiated multicenter Phase 3 ENLIGHTED trial (NCT04620239) is expected to provide further evidence on this therapy.