Cell product characterization – NeuralStem showcase

by Alexey Bersenev on September 4, 2012 · 0 comments

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The issues of cell product characterization are very important. If your cell product in development is characterized properly, the regulatory path could be fast and smooth. Likely, now we have got some examples on which we can learn. Today, I’d like to offer you one of these examples – investigational cell product NSI-566RSC, developing by NeuralStem for ALS patients and completed Phase 1 trial.

Source of cell material: Spinal cord of single 8-week fetus
Cell derivation protocol: Primary cell line was expanded in culture for 60 population doublings (~25 passages). Clinical lot was derived from passage 4 of primary cell line and included: Master Cell Bank (MCB) at passage 6, Working Cell Bank (WCB) at passage 9 and a Clinical Cell Bank (CCB) at passage 12. 399 vials of CCB at concentration 16 × 106 cells per vial were used for final formulation.
Identity of cells in WCB and MCB by flow cytometry:

>99% nestin+, 0% glial fibrillary acidic protein positive (astrocyte marker), 0% NG2+ (oligodendroglial marker), 0% TuJ1+ (neuronal marker), 0% Iba1+ (microglial marker), 0% smooth muscle actin+ (a marker of DRG-derived cells), 0% VE cadherin+ (a marker of vascular endothelial cells).

Potency: multipotent differentiation to mature neural cells from MCB, WCB and CCB measured by flow cytometry:

in vitro differentiation for 6–8 days, which resulted in approximately 50% TuJ1+ neurons and 50% glia for each bank

Mitotic stability: monitoring of population doubling rate at each passage.
Genomic stability: karyotype at passage 4 and 2 additional passages of CCB (culture from passage 12 to 14).
Tumorigenicity: (A) in vitro: colony-forming assay in soft agar and (B) in vivo:

… subcutaneous implantation of 1 × 107 cells in athymic nude mice, and after 9 months of transplantation in spinal cord of naïve and contusion-injured nude rats.

Sterility: WCB and CCB were tested for:

bacteria, mycoplasma, in vitro adventitious viruses, bovine adventitious agents, porcine adventitious agents, retroviruses, human polyomavirus BK, human cytomegalovirus (CMV), Epstein–Barr virus, hepatitis A virus, hepatitis B virus, hepatitis C virus, herpesvirus type 6, herpesvirus type 7, herpesvirus type 8, human immunodeficiency virus 1 and 2, human papillomavirus, T-cell lymphotropic virus, human polyomavirus JC, and human parvovirus B19.

Immunogenicity: Levels of HLA genes expression in undifferentiated and differentiated up to 45 days cells by Affimetrix chip.
Final formulation: one vial of CCB (16 × 106) was used for injection – washed, concentrated to 10,000 cells per microliter, resuspended in hibernation medium without antibiotics and shipped in cold overnight to the site of surgery.
Viability: checked by trypan blue in final formulation before injection. Cutoff criteria: >70% viable cells.
Toxicity (endotoxin) and sterility of final formulation: post hoc testing of retention sample at manufacturer during 14 days of surgery.
Stability during shipping: was tested 48 hours after final formulation prep by “usability for engraftment”.


The purpose of this showcase was to demonstrate how much we can learn about the cell product from published information and what developers should expect from regulatory agency to get approval for clinical trial.

I never saw such detailed description of commercial investigational cell product in the literature. I was trying to squeeze 5 paragraphs of detailed description in this post. So, if you would like to learn more details – go and read the original source. I wish, every company would provide such volume of information. So, we can learn faster and boost the progress.

Please share your thoughts on this product.

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