Consultants' Network
Consultants' Network
Case Studies with Consultants - Part II | June 23, 2025 | 11:00-12:30 EDT | Virtual
Join Featured Speakers Shahrokh, STC Biologics, and Anton Stetsenko, BioQual Consulting LLC, as they tackle key challenges in pharmaceutical development. This 1.5-hour virtual program includes speaker presentations, Q&A, and networking opportunities. Register for this free opportunity by June 20, 2025.
Consultants are a key component of CASSS membership. The purpose of the CASSS Consultants' Network is to facilitate discussions among consultants.
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Scientific Program
Case Studies with Consultants - Part II | June 23, 2025 | 11:00-12:30 EDT | Virtual
Case Study Examples of CMC Surprises
Zahra Shahrokh, STC Biologics
A few case examples of pharmaceutical challenges will be presented in this talk that demonstrate the co-dependency of a protein product’s stability and manufacturing process, manufacturing equipment, composition and contact materials. Practical lessons learned in these examples will be useful for anyone developing a protein product.
Look Up or Don't Look Up?
Anton Stetsenko, BioQual Consulting LLC
In relative format bioassay data analysis for potency estimation, it is common to average responses from all serially diluted dose replicates, fit separate four-parameter logistic (4PL) models to the reference standard and test sample, and assess similarity by comparing asymptotes, slopes, and ED50 values. However, noise in parameter estimation, especially when relying on extrapolation, can lead to false positives in non-parallelism assessments.
Building on DeLean et al. (1978), who advocated for a more efficient common-parameters approach, treating each serially diluted replicate of the reference standard and test sample as a distinct dilutional unit while sharing asymptotes and slopes across replicates is logical, informative, and robust. Using an (n+3) PL model as an extension of the 4PL (where n represents the total number of all dilutional units) enhances accuracy and precision in relative potency estimation, reduces false positives, and helps detect errors (blunders) in pre-plate dilutions, first-well transfers, and serial dilutions.
Featured Speakers Bios
Anton Stetsenko, M.D., M.B.A.
Principal Consultant
BioQual Consulting LLC
With 20 years of experience in the pharma/biotech industry, Anton Stetsenko is a consultant in CMC potency method development, validation, and troubleshooting. He specializes in in vitro enzyme activity, cell-based assays, immunoassays, and animal models. Stetsenko has worked at Abbott Laboratories, Fresenius Kabi (formerly APP Pharmaceuticals), Dynavax Technologies, Orchard Therapeutics, ADC Therapeutics, 4D Molecular Therapeutics, and Orca Bio, where he was responsible for all aspects of the potency method lifecycle including comparability studies, method transfer, personnel training, data tracking and trending, customization of data analysis, preparation of regulatory submissions, reference standards, and qualification of critical reagents. This journey allowed him to learn about CMC potency aspects specific to different biopharmaceutical products such as small molecules, biosimilars, vaccines, antibody-drug conjugates, gene and cell therapies. He holds a Doctor of Medicine degree with an emphasis on clinical biochemistry from the Russian National Research Medical University and an MBA in General Business from Lake Forest Graduate School of Management.
Zahra Shahrokh Ph.D.
Chief Development Officer
STC Biologics
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Zahra Shahrokh has over 30 years of experience in biotechnology product development with a track record in global regulatory approvals of several biologics from preclinical stage at Shire and Genentech. She was head of CMC & PD Operations and led Pharmaceutical and Analytical Development at Shire. Prior to that, she was group leader at Genentech's Pharmaceutical R&D department. As Chief Development Officer at STC Biologics, a boutique CDMO in Newton, MA, Shahrokh provides CMC Development strategy for clients and is the head of Quality. As a CMC Consultant, she provides technical and strategic CMC guidance and has authored 12 BLAs and several dozens of INDs.
Shahrokh has a PhD in Biophysics from UC Berkeley, received an NIH grant as Assistant Biophysicist at UCSF, and is a lecturer at the University of Kansas annual Graduate Biotechnology Course.
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