BOXIT-A randomised phase III placebo-controlled trial evaluating the addition of Celecoxib to standard treatment of transitional cell carcinoma of the bladder (CRUK/07/004)

Background:
Non-muscle-invasive bladder cancer (NMIBC) has a significant risk of recurrence despite adjuvant intravesical therapy.

Objective:

To determine whether celecoxib, a cyclo-oxygenase 2 inhibitor, reduces the risk of recurrence in NMIBC patients receiving standard treatment.

Design, setting, and participants:

BOXIT (CRUK/07/004, ISRCTN84681538) is a double-blinded, phase III, randomised controlled trial. Patients aged ≥18 yr with intermediate- or high-risk NMIBC were accrued across 51 UK centres between 1 November 2007 and 23 July 2012.

Intervention:

Patients were randomised (1:1) to celecoxib 200mg twice daily or placebo for 2 yr. Patients with intermediate-risk NMIBC were recommended to receive six weekly mitomycin C instillations; high-risk NMIBC cases received six weekly bacillus Calmette-Guérin and maintenance therapy.

Outcome measurements and statistical analysis:

The primary endpoint was time to disease recurrence. Analysis was by intention to treat.

Results and limitations:

A total of 472 patients were randomised (236:236). With median follow-up of 44 mo (interquartile range: 36-57), 3-yr recurrence-free rate (95% confidence interval) was as follows: celecoxib 68% (61-74%) versus placebo 64% (57-70%; hazard ratio [HR] 0.82 [0.60-1.12], p=0.2). There was no difference in high-risk (HR 0.77 [0.52-1.15], p=0.2) or intermediate-risk (HR 0.90 [0.55-1.48], p=0.7) NMIBC. Subgroup analysis suggested that time to recurrence was longer in pT1 NMIBC patients treated with celecoxib compared with those receiving placebo (HR 0.53 [0.30-0.94], interaction test p=0.04). The 3-yr progression rates in high-risk patients were low: 10% (6.5-17%) and 9.7% (6.0-15%) in celecoxib and placebo arms, respectively. Incidence of serious cardiovascular events was higher in celecoxib (5.2%) than in placebo (1.7%) group (difference +3.4% [-0.3% to 7.2%], p=0.07).

Conclusions:

BOXIT did not show that celecoxib reduces the risk of recurrence in intermediate- or high-risk NMIBC, although celecoxib was associated with delayed time to recurrence in pT1 NMIBC patients. The increased risk of cardiovascular events does not support the use of celecoxib.

Patient summary:

Celecoxib was not shown to reduce the risk of recurrence in intermediate- or high-risk non-muscle-invasive bladder cancer (NMIBC), although celecoxib was associated with delayed time to recurrence in pT1 NMIBC patients. The increased risk of cardiovascular events does not support the use of celecoxib.

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