Yes / Purpose: Despite positive responses in phase II clinical trials, the bioreductive prodrug apaziquone failed to achieve statistically significant activity in non-muscle invasive bladder cancer in phase III trials. Apaziquone was administered shortly after transurethral resection and here we test the hypothesis that haematuria inactivates apaziquone. Methods: HPLC analysis was used to determine the ability of human whole blood to metabolise apaziquone ex vivo. An in vitro model of haematuria was developed and the response of RT112 and EJ138 cells following a 1-h exposure to apaziquone was determined in the presence of urine plus or minus whole blood or lysed whole blood. Results: HPLC analysis demonstrated that apaziquone is metabolised by human whole blood with a half-life of 78.6±23.0 min. As a model for haematuria, incubation of cells in media containing up to 75% buffered (pH 7.4) urine and 25% whole blood was not toxic to cells for a 1-h exposure period. Whole blood (5% v/v) significantly (p<0.01) reduced the potency of apaziquone in this experimental model. Lysed whole blood also significantly (p<0.05) reduced cell growth, although higher concentrations were required to achieve an effect (15% v/v). Conclusions: The results of this study demonstrate that haematuria can reduce the potency of apaziquone in this experimental model. These findings impact upon the design of further phase III clinical trials and strongly suggest that apaziquone should not be administered immediately after transurethral resection of non-muscle invasive bladder cancer when haematuria is common. / Financial support from Spectrum Pharmaceuticals Inc. for the conduct of the experiments.

Le cancer de la vessie est un cancer fréquent et extrêmement onéreux par patient puisque plusieurs patients subissent des récidives de cancer et ont recours parfois à des chirurgies complexes. Il est donc important de diagnostiquer efficacement ces cancers lors de la prise en charge initiale du patient. En effet, la procédure standard d’imagerie pour la détection du cancer est la cystoscopie de la vessie guidée par lumière blanche, toutefois cette méthode ne permet pas de bien distinguer les cellules qui sont propices à l’invasion musculaire des cellules de cancer de la vessie non infiltrant. Ce mémoire propose d’utiliser un nouvel immunoconjugué fluorescent ciblant la sous-unité alpha du récepteur de l’interleukine 5, un nouveau biomarqueur spécifique aux cellules du cancer de la vessie infiltrant, afin d’effectuer la cystoscopie de la vessie guidée par fluorescence. Pour ce faire, un protocole de conjugaison du fluorochrome cyanine-5 (Cy5) à un anticorps monoclonal a été développé. De plus, un protocole de conjugaison d’un peptide Cell Accumulator (ACCUM) sur cet anticorps fluorescent (A14-Cy5-ACCUM) a été optimisé. Ensuite, la capacité de cet immunoconjugué à marquer les cellules humaines de cancer de la vessie infiltrantes du muscle (MIBC), HT1376, a été testée. Par la suite, un nouveau modèle orthotpique murin de MIBC humain permettant la validation préclinique prochaine de l’A14-Cy5-ACCUM a été développé. Une banque de plasma et sérum sanguin, et d’urine de patients sains et atteints de cancer de la vessie a été compilé. Cette biobanque contient 111 échantillons de plasma sanguin et d’urine qui pourront être utilisé afin de tester l’hypothèse selon laquelle le niveau d’interleukine-5 sanguin pourrait être un facteur pronostique pour la progression du cancer de la vessie. Ce projet jette les bases pour l’évaluation potentielle de la cystoscopie guidée par fluorescence lors de la prise en charge initiale des patients atteints de cancer de la vessie afin d’améliorer la survie sans progression et la survie à long terme des patients atteints de MIBC. / Abstract: Bladder cancer is a frequent and extremely costly cancer when evaluated on a per-patient basis because of its high recurrence rate and patients undergoing complex medical procedures. It is of utmost importance to better identify the aggressiveness of this cancer at initial diagnosis. The standard procedure for bladder cancer detection is still white-light guided cystoscopy, which relies mostly on physicians experience in regard to identifying invasive malignancies. This memoir proposes the use of a new fluorescent immunoconjugate, targeting the alpha subunit of interleukin-5 receptor (IL-5R[apha]), a new biomarker specific to muscle-invasive bladder cancer (MIBC) cells for fluorescence-guided cystoscopy. To do so, a conjugation protocol to fluorescently label a monoclonal antibody with cyanine-5 fluorophores has been developped. Then, a conjugation protocol to attach Cell Accumulator (ACCUM) peptides to this fluorescent immunoconjugate (A14-Cy5-ACCUM) has been optimized. Moreover, the ability of A14-Cy5-ACCUM to stain MIBC cell line HT1376 has been tested. Most importantly, a novel orthotpic rat model of human MIBC for the future preclinical validation of fluorescence-guided cystoscopy in rat bladder has been developped. Finally, a new bladder cancer tissue repository at the CHUS has been established. This repository contains a total of 111 plasma and urine patient samples that will be helpful to evaluate if interleukin-5 blood levels could be used as a prognosis marker for bladder cancer progression. This project laid the basis for the potential evaluation of fluorescence-guided cystoscopy during initial diagnosis of bladder cancer patients to improve their disease-free and long-term survival.