The purpose of this Study is to find out if dabogratinib, also known as TYRA-300 (which is also known as "Study Drug") is safe and effective at treating low grade upper tract urothelial cancer. Some patients have a certain alteration, or mutation, in the FGFR3 gene (a protein in the body) that can lead to cancer. The Study Drug is an experimental treatment (not approved by the United States Food and Drug Administration [FDA] or any other regulatory agencies) that blocks the abnormal activity of FGFR3 in cancer cells which might be "driving" this type of cancer.
Most patients with this type of cancer have the FGFR3 alteration in their tumor(s) but there are some patients who do not. Participants that join this study could be on it for a few months up to 24 months.

This study is for patients who have been diagnosed with low grade, intermediate risk non-muscle invasive bladder cancer. It is testing an investigational drug called TYRA-300. "Investigational" means that the drug has not been approved by the United States Food and Drug Administration (FDA).

The purpose of the study is to see whether TYRA-300 can shrink or eliminate bladder tumors without surgery. Normally, standard care involves a surgery called transurethral resection of bladder tumor (TURBT), but in this study at least one tumor will remain in place to see if the study drug works. The study will also evaluate the genetics of the cancer to see if certain mutations or changes in proteins affect how the drug works.

TYRA-300 is taken by mouth once daily. The dose level will be assigned by the study doctor. Participants may be in the study for about 36 months, which includes a screening period (up to 28 days), a study treatment phase (with visits every 4 weeks and more frequent visits during the first 8 weeks), an end-of-treatment visit, a safety follow-up about 28 days later, and long-term follow-up every 12 weeks. There will be a total of 3 patients enrolled locally over the course of 12 months.