A pharmaceutical composition is described, essentially consisting of the paclitaxel prodrug associated with pharmacologically acceptable diluents/excipients, for use in the treatment of non-muscle invasive bladder cancer (NMIBC) by means of intravesical instillations according to a single weekly dose of 600 mg of said prodrug, or two weekly doses equal to a total of 1,200 mg, for 12 or 6 consecutive weeks of treatment. The paclitaxel prodrug used was prepared according to an indirect synthesis process between molecules of hyaluronic acid (HA) and paclitaxel by introducing a spacer (4-bromobutyric acid) between the hyaluronic acid and chemotherapeutic agent.