For stem cells 'the process is the product,' says Pluristem

“In order to succeed in the cell therapy industry, you need to have a good and potent cell source, you need the ability to produce trillions of high quality cells per batch in order to supply the clinic on demand, [and] you need a reproducible process,”​ Lior Raviv, VP of Development at Pluristem Therapeutics, told delegates earlier this month at the 1st Stem Cell Community day in Germany, organised by Eppendorf.

“And of course you need to think about reducing the cost of goods so we make some money from our products.”​

But a lack of suitable scale-up technologies​ has hindered the burgeoning stem cell therapy market, something the Israeli biotech has been addressing in-house for over a decade.

Now, through its process development process, the firm has what it says is a 3D scalable, closed system, automated and GMP compliant production method for its allogeneic stem cell therapies consisting of a pack bed bioreactor

“After a few years of working with this system we actually scaled it up from a 2.5L bioreactor with 30g of scaffold to a 15L bioreactor with 375g – equals to around 160 cell factories,”​ Raviv said.

Process Development​

“In 2006, when we started our process development, the most used technology was a 2D-based ten-layer cell factory, but we evaluated it and found there were many gaps, most of them around manual operations, and poor process controls,” ​he said, adding scaling-up such a system (essentially through adding more cell factories) produces differences between vessels which are not easily noticed or controlled.

But to get to where the company is today – i.e. ready to produce stem cells for upcoming Phase II trials of its lead candidate, PLX-PAD for Critical Limb Ischemia – it had to take a quality by design (QbD) approach.

“The goal of process development is you take an idea and just form it into a product while maintaining the product’s specification. You need to think where you want to get to at the end and start developing the process around that immediately,”​ Raviv said.

“The process directly affects the product and in a cell therapy this effect has a crucial impact on the product as these cells are alive and interact with everything we do,” he continued, adding this was factored when Pluristem began planning its process development.

“Changing the environment changed the product. We saw dramatic changes when changing the systems [and] understanding this early in development was critical as this could change our product if [the process is] change this during clinical development.”​

And to a packed out room in Hamburg, he therefore offered advice for potential stem cell therapy developers:

“Master three fields: the biology, the engineering, and understand the quality and regulation around your product. Only a true combination of these three will give you a quality product.”​