From patients with intermediate risk non-muscle invasive bladder cancer tumor (NMIBC) specimens will be harvested during transurethral resection. Fresh specimens will be cultured as patient derived organoids (PDO). After approx. 10 days, PDO are exposed to different drugs that are used as intravesical instillation agents in these patients (epirubicin, mitomycin, gemcitabine, docetaxel). After 2 days of exposure, PDO viability will be measured. The drug with the highest antitumor effect on PDO will be applied as weekly intravesical instillations 6 times. Thereafter, patients are followed according to the standard of care.

Inclusion Criteria:

• Age ≥ 18 years
• Signed Informed Consent Form
• ECOG performance status of 0 or 1
• Histologically confirmed intermediate risk non muscle-invasive urothelial carcinoma of the bladder (pTa low grade) Patients
• Representative fresh tumor specimen for PDO generation and drug screen

Exclusion Criteria:

• Known previous high grade and/or high risk non muscle-invasive bladder cancer
• Previous Intravesical biological/immuno (BCG) therapy
• Pregnancy or nursing
• Evidence of significant uncontrolled concomitant disease that could affect compliance with the protocol
• Severe infection within 4 weeks prior to cycle 1, day 1
• Contraindication for frequent catheterization
• Voiding dysfunction
• Pregnancy or nursing
• Female subject of childbearing potential who is unwilling to use acceptable method(s) of effective contraception during study treatment and through 6 months after the last treatment.
• Male subject who is unwilling to use acceptable method of effective contraception during IP treatment and through 6 months after the last dose of IP.