• Participants age 18 and over of informed consent and willing and able to comply with all requires study procedures

• Able to understand and given written informed consent

• Participants with histologically confirmed low-grade NMIBC within 6 weeks prior to randomization with prior diagnostic biopsy/TURBT to confirm stage and grade and with at least 3 mm and no more than 12 mm total (1/2 a resectoscope loop to 2 loops, refer to Section 8.1.5) residual visible tumor as a marker lesion(s) left behind:

‣ Ta low grade

⁃ T1 low grade

• Participants must have intermediate risk NMIBC, defined as having any of the following characteristics (AUA Guidelines, 2024)

‣ Recurrence within 1 year, LG Ta

⁃ Solitary LG Ta \>3cm

⁃ LG Ta, multifocal

⁃ LG T1

• Documented activating FGFR3 mutation or fusion (Appendix 4)

• Have undergone bladder mapping and identification of visible marker lesion(s) within 6 weeks prior to randomization (refer to Inclusion Criterion #3)

• No evidence of urothelial carcinoma of the upper urinary tract (confirmed by imaging) or prostatic urethra within 6 months of randomization

• No prior BCG administration within 1 year of date of consent.

• No intravesical chemotherapy within 8 weeks prior to C1D1.

• ECOG 0-1

• Pathology consistent with pure urothelial carcinoma; if mixed histology, ensure that at least 80% of the sample is urothelial

• Adequate bone marrow, liver, and renal function:

• b. Bone marrow function: i. Absolute neutrophil count (ANC) \> or = 1,500/mm3 ii. Platelet count \> or = 75,000/mm3 iii. /hemoglobin \> or = 10.0 g/dL e. Liver function: i.Total bilirubin \< or = ULN ii. Alanine aminotransferase (ALT) \< or = ULN iii. Aspartate aminotransferase (AST) \< or = ULN f. Renal function: i. estimated glomerular filtration rate \>60 mL/min calculated using the modification of diet in renal disease equation or CKD-EPI formula ii. Serum Phosphate level \< or = ULN prior to starting treatment g. Coagulation i. International normalized ratio (INR) \< or = 1.5 x ULN

• Ability to swallow tablets

• Participants (male and female) of child-bearing potential (including females who are post-menopausal for less than 1 year) must be willing to practice effective contraception while on treatment and be willing and able to continue contraception for 3 months (males) and 6 months (females) after the last dose of study treatment. Potential male participants should consider the potential impact of TYRA-300 on their ability to father a child and discuss options with the site study staff.

• Potential participants who are positive for human immunodeficiency virus (HIV) must have a viral load below the limits of detection and on stable antiretroviral therapy for at least 3 months prior to C1D1. NOTE: some of the compounds in antiretroviral therapy may be on the prohibited medications list. Allowances will be made to ensure the participant's HIV treatment continues uninterrupted following a discussion with the Sponsor's medical monitor. A discussion of the impact of the antiretroviral therapy on TYRA- 300 needs to be discussed with the potential participant prior to C1D1.

• Potential participants with chronic hepatitis B virus (HBV) infection with active disease should be on a suppressive antiviral therapy prior to C1D1.

• Potential participants patients with a history of hepatitis C virus (HCV) infection should have completed curative antiviral treatment and must have a HCV viral load below the limit of quantification.

• Potential participants with a history of HCV infection and on current treatment must have a HCV viral load below the limit of quantification