IMPORTANCETreatment options for platinum-refractory metastatic urothelial cancer (mUC) are limited, and outcomes remain poor. Nab-paclitaxel is an albumin-bound formulation of paclitaxel showing promising activity and tolerability in a prior single-arm trial.OBJECTIVES To evaluate the efficacy and safety of nab-paclitaxel vs paclitaxel in platinum-refractory mUC. DESIGN, SETTING, AND PARTICIPANTSIn this investigator-initiated, open-label, phase 2 randomized clinical trial conducted across Canada and Australia from January 2014 to April 2017, eligible patients had histologically confirmed, radiologically evident mUC of the urinary tract. Mixed histologic findings, except small cell, were permitted provided UC was the predominant histologic finding. All patients had received platinum-based chemotherapy either in the metastatic setting or were within 12 months of perioperative chemotherapy. Patients with prior taxane chemotherapy were not included. Patients had an Eastern Cooperative Oncology Group Performance Status (ECOG PS) 0 to 2 and adequate organ function.INTERVENTIONS Patients were randomized to nab-paclitaxel, 260 mg/m 2 , or paclitaxel, 175 mg/m 2 , every 3 weeks. MAIN OUTCOMES AND MEASURESThe primary end point was progression-free survival (PFS). RESULTS Among 199 patients, median age was 67 (range, 24-88) years; 144 (72%) were men; 167 (84%) were ECOG PS 0-1; 59 (30%) had liver metastases; and 110 (55%) were within 6 months of prior platinum-based chemotherapy. At a median follow-up of 16.4 months, there was no significant difference between nab-paclitaxel vs paclitaxel for median PFS (3.4 months vs 3.0 months; hazard ratio [HR], 0.92; 90% CI, 0.68-1.23; 1-sided P = .31). Median overall survival was 7.5 months for nab-paclitaxel vs 8.8 months for paclitaxel (HR, 0.95; 90% CI, 0.70-1.30; 1-sided P = .40); and objective response rate (ORR) was 22% for nab-paclitaxel vs 25% for paclitaxel (P = .97). Grade 3/4 adverse events were more frequent with nab-paclitaxel (64/97 [66%]) compared with paclitaxel (45/97 [46%]), P = .009; but peripheral sensory neuropathy was similar (all grades, 72/97 [74%] vs 64/97 [66%]; grade 3/4, 7/97 [7%] vs 3/97 [3%]; P = .27). There were no apparent differences in scores for health-related quality of life. CONCLUSIONS AND RELEVANCEIn this open-label, phase 2 randomized clinical trial of patients with platinum-refractory mUC, nab-paclitaxel had similar efficacy to paclitaxel; but worse toxic effects. The ORR with either taxane, however, was higher than previously reported and similar to those reported for the immune checkpoint inhibitors, suggesting that the taxanes remain a reasonable option in this setting.

PSA declines and stable disease were observed with a combination of sorafenib and bicalutamide including in patients previously progressing on bicalutamide. Strategies to combine multi-targeted kinase inhibitors with hormonal therapies warrant further study in patients with CRPC.

Primary PDXs of CRPC can be established from TURP specimens with modest success. The take rate can be increased if the original tissues contain sufficient numbers of actively proliferating cancer cells. Selecting specimens with abundant viable cancer will maximize the rate of engraftment and increase the efficiency of establishing PDXs that can be serially transplanted.

Patupilone at 8 mg/m2 was tolerable, had antitumor activity, and was associated with symptomatic improvement in patients previously treated with docetaxel.