(UroToday.com) While cisplatin-based chemotherapy is a first-line treatment for muscle-invasive and metastatic bladder cancer, only a subset of patients responds to therapy. Nearly 15% of urothelial tumors have a somatic missense mutation in ERCC2, a nucleotide excision repair (NER) gene that confers increased sensitivity to cisplatin. However, a significant percentage of patients are ineligible for cisplatin-based therapy due to medical contraindications, and no NER-targeted approaches are available for platinum-ineligible or platinum-refractory ERCC2 mutant cases.