Visible and subvisible particles in the BCG immunotherapeutic product ImmuCyst®

Bacille Calmette–Guerin, BCG, is a live attenuated bovine tubercle bacillus used for the treatment of non-muscle invasive bladder cancer. In this study, an Electrical Sensing Zone (ESZ) method was developed to measure the particle count and the size of BCG immunotherapeutic (BCG IT), or ImmuCyst® product using a Coulter Counter Multisizer 4® instrument. The focus of this study was to establish a baseline for reconstituted lyophilized BCG IT product using visible and sub-visible particle concentration and size distribution as reportable values. ESZ method was used to assess manufacturing process consistency using 20 production scale lots of BCG IT product. The results demonstrated that ESZ can be used to accumulate product and process knowledge of BCG IT.