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esponse of Multiple Recurrent TaT1ladder Cancer to Intravesical ApaziquoneEO9): Comparative Analysis of Tumorecurrence Rates

run Jain, Roger M. Phillips, Andrew J. Scally, Gino Lenaz, Mario Beer, and Rajiv Puri

BJECTIVES Previous studies have demonstrated that intravesical administration of apaziquone (EOquin) hasablative activity against superficial bladder cancer marker lesions with 8 out of 12 completeresponses recorded. We present a comparison between the rates of tumor recurrence before andafter treatment with apaziquone.

ETHODS The rate of tumor recurrence after treatment with apaziquone was compared with each patient’shistorical record of recurrences obtained from a retrospective analysis of the patients’ case notes.The time to each recurrence event before apaziquone treatment and the time to the firstrecurrence after apaziquone treatment were recorded, and the data were analyzed using apopulation-averaged linear regression model using Stata Release, version 9.2, software.

ESULTS Of the eight complete responses obtained in the Phase I study, tumor recurrence occurred in 4patients and the remaining 4 patients remained disease free after a median follow-up of 31months. The time to the first recurrence after apaziquone treatment was significantly longer(P �0.001) compared with the historical pattern and recurrence interval before apaziquone.Before apaziquone instillation, the mean � SE recurrence rate and tumor rate per year was 1.5 �0.2 and 4.8 � 1.2, respectively, and these decreased to 0.6 � 0.25 and 1.5 � 0.8, respectively,after apaziquone treatment (P �0.05).

ONCLUSIONS The results of this study indicate that early recurrences after treatment with apaziquone areinfrequent and the interval to recurrence is significantly greater compared with the historicalrecurrence times for these patients. Larger prospective randomised trials are warranted to confirm

these results. UROLOGY 73: 1083–1086, 2009. © 2009 Elsevier Inc.

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apaziquone (EOquin, USAN, E09, 3-hydroxy-5-aziridinyl-1-methyl-2[indole-4,7-dione]–prop-�-en-�-ol) belongs to a class of anticancer agents

nown as bioreductive drugs that require metabolism byellular reductases to generate a cytotoxic species.1 Al-hough it is chemically related to mitomycin C, apazi-uone has a distinctly different mechanism of action andreclinical activity profile.1,2 The initial optimism gen-rated by its preclinical activity profile rapidly evaporatedfter the demonstration that intravenously administered

he study was financially supported by Cancer Research UK (grant C459/A2579) andpectrum Pharmaceuticals, Incorporated.G. Lenaz and M. Beer are employed by Spectrum Pharmaceuticals, who sponsored

his study in part.From the Department of Urology, Bradford Teaching Hospitals Foundation Nationalealth Services Trust, Bradford Royal Infirmary, Bradford, United Kingdom; Institute

f Cancer Therapeutics, University of Bradford, United Kingdome; University ofradford School of Health Studies, Bradford, United Kingdom; and Spectrum Phar-aceuticals, Irvine, CaliforniaReprint requests: Rajiv Puri, M.S., F.R.C.S. (Urol), Department of Urology, Bradford

toyal Infirmary, Bradford BD9 6RJ United Kingdom. E-mail: r.puri@btinternet.comSubmitted: July 23, 2007, accepted (with revisions): December 13, 2007

2009 Elsevier Inc.ll Rights Reserved

paziquone was clinically inactive against a range of solidumors in Phase II clinical trials.3,4 Several possible ex-lanations were considered for its lack of efficacy, butoor drug delivery to the tumor because of the rapidharmacokinetic elimination of apaziquone in conjunc-ion with relatively poor penetration through avascularissue was considered to be the principal reason.5 On theasis of the rationale that intravesical administrationould circumvent the problem of drug delivery and anypaziquone absorbed into the blood stream would beapidly cleared,6 a Phase I-II clinical pilot study of intra-esical administration of apaziquone to superficial blad-er tumors was established.7 The results of that trialemonstrated that intravesically administered apaziquoneas ablative activity against superficial bladder transi-ional cell carcinoma (TCC) marker lesions.7 These re-ults were confirmed and extended in a Phase II clinicalrial of 47 patients with superficial bladder TCC, inhich complete responses were obtained in 67% of pa-

ients.8 Because all the enrolled patients in the original

rial7 had had multiple recurrences after previous intra-

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esical chemotherapy and/or immunotherapy, the pur-ose of the present study was, first, to report the recur-ences that occurred after apaziquone treatment and,econd, to study the effect of apaziquone instillation onhe recurrence rate by statistically comparing these re-ults with the historical pattern of recurrences for eachatient before treatment with apaziquone.

ATERIAL AND METHODS

he details of the recruitment process have been previouslyescribed.7 In brief, 12 patients were enrolled, each of whomad a history of multiple recurrences after surgery and intraves-

cal treatment using conventional chemotherapeutic agentsnd/or bacille Calmette-Guérin. The first cohort of 6 patientsnrolled received escalating doses of apaziquone (administerednce a week for 6 weeks) to establish a safe dose, and theemaining cohort of 6 patients received a course of apaziquonet this dose (4 mg/40 mL administered once a week for 6eeks). Four complete responses, as defined by the ablation ofsingle marker lesion, were obtained in the first cohort of

atients and an additional four complete responses were ob-ained in the second cohort of patients. For each patient, theistory of treatment and recurrences before enrollment in thepaziquone trial was recorded by retrospective case note review.he interval between each recurrence event was recorded inonjunction with the total number of tumor recurrences andhe treatment received at each event. After treatment withpaziquone, all patients were followed up by check cystoscopy at, 5, 8, 12, 18, and 24 months after the first instillation ofpaziquone. If a recurrence was observed at any point, the nextollow-up cystoscopy was performed after 3 months, and addi-ional treatment was instituted depending on the nature of theecurrent TCC. For the purposes of this analysis, the interval tohe first recurrence after apaziquone was recorded in each pa-ient, and the patient was censored when any additional treat-ent was started. For patients who remained disease free at

heir last follow-up cystoscopy, the interval between the start ofpaziquone treatment and the last cystoscopy was considered toe the time to the first recurrence (ie, for the purposes oftatistical analysis, it was recorded as a recurrence event). Theata were analyzed using a population-averaged linear regres-ion model that accounted for the within-subject correlation ofhe time to the next recurrence. The primary focus of the studyas to evaluate the effect of the administration of apaziquonen the mean time to the first recurrence after apaziquonedministration. The cumulative follow-up time was also in-luded in the model, because it was thought that this mightffect the average time between recurrences in the preapazi-uone administration period. The analysis was performed usingpopulation averaged linear regression model using Stata, re-

ease 9.2.

ESULTShe tumor grade and stage at the start of apaziquone

nstillation for each patient is given in Table 1. Figure 1s a graphic representation of the treatment history and

ecurrence episodes for each patient in the form of a w

084

imeline. Before treatment with apaziquone, most pa-ients had had a long history of recurrences after surgerylone or surgery plus intravesical chemotherapy and/or ba-ille Calmette-Guérin. Of the 8 patients with a completeesponse to apaziquone in the clinical pilot study, 4atients developed recurrences. These recurrences werell Stage Ta and grade 1-2 tumors with no evidence oftage or grade progression. The remaining 4 patientsemained disease free after a median follow-up of 31onths without requiring any additional treatment. Ad-

itionally, 1 of the 4 patients classified as a nonrespondern the pilot study remained recurrence free after resectionf the marker lesion. The median time to the first recur-ence after apaziquone treatment was 21.5 months com-ared with the median time to recurrence (after the lastransurethral resection [TUR]) before apaziquone instil-ation of 8.4 months. Statistical analysis using a popula-ion-averaged linear regression model demonstrated thathe interval to the first recurrence after treatment withpaziquone was significantly increased by an average of 15eeks (P �0.001) compared with the patterns and fre-uency of recurrences before apaziquone treatment. This

Table 1. Tumor stage and grade at start of apaziquonetreatment

Pt. No. Tumor Stage and Grade

1 pTa G22 pTa G13 pTa G24 pT1 G25 pTa G26 pTa G17 pTa G18 pTa G29 pTa G2

10 pTa G211 pTa G212 pT1 G2

Patients 1 to 6 represent first (dose escalation) cohort, andpatients 7 to 12, second (fixed dose) cohort.

igure 1. Treatment and response history before and afterreatment with apaziquone for 12 patients enrolled in initialhase I-II pilot study. Results of each patient expressedeparately on timeline normalized to start of apaziquonereatment (t � 0).

as likely a conservative estimate because the 4 patients

UROLOGY 73 (5), 2009

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33%)who had no recurrence after apaziquone were alsoonsidered to have had a recurrence at their last fol-ow-up visit for the purposes of this analysis, as indicatedreviously. Furthermore, the mean � SE recurrence rateer year and tumor rate per year also decreased signifi-antly from 1.5 � 0.2 and 4.8 � 1.2, respectively, beforepaziquone treatment to 0.6 � 0.25 and 1.5 � 0.8,espectively, after apaziquone treatment. The details ofll the adverse events noted in the early postinstillationeriod have been previously published.7 No long-termoxicity was noted.

OMMENTuperficial TCC of the bladder is a highly prevalentrologic malignancy with low mortality but a high recur-ence rate. Intravesical chemotherapy and immunother-py have been conclusively shown to decreases the inci-ence of tumor recurrence after primary resection,9,10 butarked heterogeneity in the recurrence rates exist, with

ome patients developing recurrence early and othersith histologically identical tumors remaining disease

ree for several years. Following the demonstration thatpaziquone has ablative activity against superficial TCCarker lesions, the present study has provided the first

ndication that recurrences during short-term follow-upfter treatment with apaziquone are infrequent and thathe time to the first recurrence is significantly greaterompared with each patient’s history of recurrence afterther treatment regimens.The comparisons between these results and the results

f previous trials are difficult to interpret because ofifferences in study design and patient numbers. Never-heless, in a Phase II study11 involving 9 patients withuperficial TCC treated with intravesical gemcitabine000 mg weekly for 4 weeks, only 2 patients (22%) wereecurrence free after 2 years of follow-up. In a randomizedontrol trial comparing TUR plus intravesical mitomycin

versus TUR alone, a recurrence rate of 41% wasbtained in the TUR plus mitomycin C treatment arm.12

n another study by Oosterlinck et al.,13 comparing epi-ubicin with the instillation of water, the overall recur-ence rate decreased by a factor of 1.9 and the tumor ratey a ratio of 1.8 in the treatment group after a meanollow-up of 25 months. However, in the subgroup ofatients with recurrent TCCs, the recurrence rate did notmprove significantly.

Our results compare favorably with the results of thesetudies, and several pieces of additional evidence exist touggest that these findings are significant. Because thetatistical test required an interval to the first recurrencealue for all patients, the last cystoscopy for the 4 pa-ients who had no recurrences was entered into theatabase as a “recurrence event.” The statistical analysisonducted resulted therefore in an overestimate of therue recurrence rate. Also, the tumor loads and timing of

ntravesical treatment relative to surgery would have

ROLOGY 73 (5), 2009

een very different before and after apaziquone. Thus,efore apaziquone, all tumors were removed and intra-esical treatments were administered generally within 24ours. In contrast, treatment with apaziquone involvedhe retention of a marker lesion plus a delay in drugdministration of 2 weeks after surgery. Furthermore,ost patients enrolled had received previous chemother-

py and/or bacille Calmette-Guérin, suggesting a high-isk cohort was enrolled in the study. Additional studiesre required to assess the recurrence rates in treatment-aive patients.

ONCLUSIONShe results of this study have provided the first indication

hat early recurrences after intravesical apaziquone arenfrequent and provided statistically significant evidenceo suggest that the interval to recurrence after apaziquonereatment is longer compared with the patient’s previousistory of recurrences after other treatments. Althoughaution should be exercised in the interpretation of thesendings because of the low number of patients involvedn this study, the results are encouraging and stronglyupport the continued development of apaziquone for thereatment of Stage Ta-T1 bladder cancer.

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