Login to Access Video or Poster Abstract: MP21-01
Sources of Funding: none

Introduction

Response rates to salvage intravesical therapies for Bacillus Calmette-Guerin (BCG) - refractory non-muscle-invasive bladder cancer (NMIBC) range from 10 to 30%. We previously reported the results of a phase II trial of salvage intravesical nanoparticle albumin-bound (nab)-paclitaxel, which demonstrated minimal toxicity and a 36% response rate. We now present an update on this cohort with long-term follow-up.

Methods

This was an investigator initiated, single-center, single-arm, phase II trial investigating the use of intravesical nab-paclitaxel in patients with recurrent Tis, Ta, and T1 urothelial carcinoma who failed at least one prior induction course of intravesical BCG. Patients received 500mg/100mL of nab-paclitaxel administered as 6 weekly intravesical instillations. At 6 weeks after the final instillation, response was evaluated by cystoscopy with biopsy, cytology, and cross-sectional imaging and any positive element constituted a recurrence. All complete responders (CR) were started on full-dose monthly maintenance for 6 months. Overall survival (OS), recurrence-free survival (RFS), cystectomy-free survival (CFS), and cancer-specific survival (CSS) were assessed via Kaplan-Meier analysis.

Results

A total of 28 patients were enrolled with a median follow-up of 41 months (range 5-76). There were 22 men and 6 women with a median age of 79 (range 36 - 93) and the median number of prior intravesical therapies was 2. Twenty-one of 28 (75%) were BCG refractory at enrollment. Ten of the 28 (36%) patients achieved CR at cystoscopy 6 weeks after their last nab-paclitaxel instillation. Six of the 28 patients remain cancer free, with RFS of 18%. 5-year OS was 56% and 5-year CSS was 91%. Radical cystectomy was performed in 11/28 (39%) patients, of whom only 2/11 (18%) had pT2 or greater disease.

Conclusions

With a median follow up of 41 months, 18% of this cohort of high risk BCG unresponsive NMIBC patients treated with nab-paclitaxel were disease free. Cystectomy free survival was 61% and bladder cancer-specific mortality was 9%. Nab-paclitaxel is a reasonable treatment option in this high risk population.

Funding

none