Yesterday, Stem Cell Reports published “must read” paper, which describes manufacturing of GMP-grade iPS cell line for potential clinical use. We saw a few very similar paper titles in in the past, but this one is special. Here is why:
- This is the first (as claimed by authors) fully GMP-compliant manufacturing protocol for generation of iPS cell master bank. “Fully” means a lot here, because previous protocols were lacking appropriate donor consents, determination of donor eligibility, appropriate process validation steps and quality control testing.
- It is in open access and it is the most detailed protocol ever published.
- Even though, the paper describes one process development, it gives a global framework to any cell product developer. Such general principles as donor eligibility, validation and engineering runs, in-process assays and quality control testing were greatly emphasized in the paper.
- As result of process development at Lonza, drug master file (DMF) was filed with FDA and available for developers. Ready to use DMF for clinical master cell bank means a lot, guys! You can save couple years of your time and tons of money for product and process development if use available iPS line with DMF. Take (buy) it and develop your own unique product from it! You can also hire Lonza to develop your specific master cell bank, using the same processes.
- This protocol was developed (partly) as “public good” to stimulate stem cell clinical developers and was funded by government:
“We didn’t want Lonza to own the process, even though they helped develop it,” Rao said, speaking on his own behalf. “We wanted the government to be able to provide the process to people, so they could modify it or have access to the process at a reasonable cost. That was one reason why the government funded this … All the basic processes will be free.”
I have few general consideration about this protocol and few technical. Let’s start from general:
Since, I’m as US taxpayer also funded this study, I’d like to have an option for process tech transfer to my facility. If not Lonza, who is owner of this process? Can I get a license and do the same thing in-house? The process largerly developed on Lonza’s reagents and platforms (such as nucleofection). Also, proprietary reagent and process were mentioned in the paper. I’d be ok to buy Lonza’s reagents for this wonderful process, but what if I’d like alternative to reduce the cost? Also, in GMP must be back-up supplier for every reagent and material. Who is back-up for Lonza?
Now, some technical considerations:
- Described process seems to me very expensive, because includes CD34+ cell isolation and culture as iPS cell source plus some other things. Here is my advice, guys: if you want to cut down about 10k of cost from you manufacturing process:
– avoid CliniMACS
– avoid electroporation (clinical devices and reagents are very expensive)
– avoid cryopreservation of source material and culturing it after thaw – do it all fresh!
- I didn’t understand why they did priming of CD34+ cells for 4 days before proceed to iPS cell generation. They boost CD34 purity from 89 to 95% in doing this step, but I bet the culture increased CD34+ cells heterogeneity. Add here cytokines and media cost.
- Another flaw in the process is a donor material (they used cord blood). The results of donor eligibility (which include testing for infectious communicable diseases and screening for health risks) were not ready before starting manufacturing, so the whole process was done under quarantine. But what if donor turns out ineligible due to positive tests? You have to dump your cells and 10-20k will get wasted!
- GMP process did not exclude heterogeneity and generation of “defective clones” (another money waster). For example, some clones were not cleared from plasmid and different number of colonies were generated between runs, possibly related to variability of donor’s material.
- There was no high resolution genomic stability testing performed for QC and release. What about sequencing, SNP and CGH? Or take RIKEN approach for iPS cell-based therapeutic release testing.
- Finally, the protocol is not 100% xeno-free.
Overall, I was enjoying reading this paper. I’d highly recommend this protocol to every cell product developer, irrespective to type of your cells!