Plain language summary of erdafitinib in locally advanced or metastatic urothelial carcinoma: a phase 2 study with long-term follow-up

WHAT IS THIS SUMMARY ABOUT?: This is a plain language summary of two articles describing the results from a study called BLC2001. The study examined the effect of a medication called erdafitinib on participants with a type of cancer known as urothelial carcinoma that had either spread beyond the bladder or urinary tract into surrounding organs and/or nearby muscles (locally advanced) and was not removable by surgery (unresectable) or had spread to other parts of the body (metastatic). In this study, researchers wanted to learn if erdafitinib was safe and effective at stopping or reducing tumor growth in participants with locally advanced and unresectable or metastatic urothelial carcinoma with certain genetic alterations (changes in DNA sequence) in two related genes called fibroblast growth factor receptor 2 (FGFR2) and 3 (FGFR3). Treatment options for people with this disease are very limited; some may not have responded to other therapies, or their tumors continued to grow after they received other treatments. 212 participants took part in the study. 111 participants were treated with oral (by mouth) erdafitinib at different doses to find a recommended dose regimen. 101 additional participants then received the recommended starting dose of erdafitinib at 8 mg daily with possible increase to 9 mg daily, these participants make up the 8 mg regimen group. WHAT WERE THE RESULTS OF THE BLC2001 STUDY IN THE 8 MG REGIMEN GROUP?: Researchers found that tumors decreased in size or completely disappeared in 40% of participants. With approximately 1 year of follow-up, an estimated 55% of participants were still alive, and after 2 years, an estimated 31% of participants were still alive. Common side effects of erdafitinib included high phosphate levels in the blood (hyperphosphatemia), an inflamed and sore mouth, diarrhea, and dry mouth. WHAT DO THE RESULTS MEAN?: Participants had locally advanced and unresectable or metastatic urothelial carcinoma with certain FGFR gene alterations that had been treated with erdafitinib after previous chemotherapy and/or a type of medicine that uses the immune system to help the body fight cancer (immunotherapy). The BLC2001 study found that some participants treated with 8 mg erdafitinib had the benefit of a longer period without their cancer growing or spreading to other parts of the body. About 80% of participants achieved some level of disease control where their tumor shrank or remained stable.