Mesenchymal Stromal Stem Cells: Next Steps and Considerations for CGMP Manufacturing

Massimo Dominici is scientific founder of Rigenerand srl, a joint venture between RanD (a biomedical company producing bioreactors for liver support and chemohyperthermic technology for cancer) and experts in cell and gene therapy at the University of Modena and Emilia Region in Italy. Rigenerand develops and manufactures medicinal products for cell-therapy applications (primarily for regenerative medicine and oncology) and three-dimensional (3D) bioreactors as an alternative to animal testing for preclinical investigations. The company also produces its own pipeline of cell and gene therapies for cancer treatment and operates a contract development and manufacturing (CDMO) division that provides good manufacturing practice (GMP) support for scaling up of cell-based medicinal products. Headquartered in Medolla, Italy, Rigenerand is developing a proprietary gene therapy for treating patients with pancreatic ductal adenocarcinoma (PDAC). It has been granted orphan drug designation by both the US Food and Drug Administration (FDA) and the European Medicine Agency (EMA), with a phase 1 clinical trial beginning this year.

With a medical doctorate from the University of Pavia, Dominici served a postgraduate internship at Vienna University in Austria and a postdoctoral position at St. Jude Children’s Hospital in Memphis, TN, before his residency in hematology at the University of Ferrara in Italy. Currently he is a hospital physician, an associate professor of medical oncology, head of the cell-therapy laboratory, director of the residency school in medical oncology, and a faculty member of the doctoral school of molecular and regenerative medicine at the University of Modena and the Emilia Region in Italy. Dominici has published more than 120 papers and cofounded the Mirandola Science and Technology Park in Modena, Italy. He is a scientific advisor for the Italian Minister of Health and was president of the International Society of Cell and Gene Therapy (ISCT), for which he now serves as chair of the advisory board and the presidential task force on unproven cell therapies.

This past spring, we discussed the current state of mesenchymal stem cell (MSC) research and development (R&D) and renewed interest in the field — and explored what it will take to move this cell therapy modality forward.

Rigenerand’s facility has cleanrooms, a quality control laboratory, a controlled warehouse, and a cryogenic room for cell banking. The cleanrooms occupy 450 m² of classified area with dedicated access corridors and a Class D material-transfer zone.

Our Conversation
Why are drug companies pursuing MSC-based therapies? There has been significant interest in them for years. Clinical trials have proceeded in parallel with R&D, yielding better understanding about the potential of MSCs. Rigenerand mostly works with gene-modified cells, with one of their major advantages being a capacity for high levels of gene modification with little donor-to-donor variability. We can gene-modify >90% of MSCs, which is unique among cell and gene therapy products especially if you compare such performance with that of chimeric antigen-receptor (CAR) T-cell treatments. Even a major company such as Novartis has experienced a 10–15% failure rate in expanding CAR-T cells, suggesting that one in 10 patients did not get the cells they needed. That is seldom a problem with MSC products. CAR-T transduction efficiency is lower than that of MSCs as well — even if, after target recognition, you add selective amplification of a CAR-T clone in vivo. That’s unnecessary with MSCs. So I think that MSCs are promising tools for cell and gene therapy.

Is variability in donor material a concern? Yes, that is a key question. Rigenerand started working with bone-marrow MSCs, and we wanted to gene-modify them as anticancer agents. But after transfection, the cells stopped growing — so expressing the anticancer protein was slowing down their proliferation. We realized that not all MSCs are good for that anticancer approach. When we tested adipose-derived MSCs, we found that they were fully compatible with the anticancer molecule delivery. We could have production of the anticancer protein without toxicity to the cells. MSCs in cancer can act as “Trojan horses” within a tumor microenvironment. Essentially, you want them to deliver soldiers (the anti-cancer ligands in that environment), but you don’t want those soldiers to kill the horse (the MSC) in the process. That depends on the specific protein that you are engineering the cells to produce. Not all MSC sources are a good fit for every program. Developers need to find the proper combination of cell and expressed protein, particularly if those ligands induce apoptosis.

We’re generating unique adipose-based modalities that are important assets for our company. We collect a very small amount of adipose tissue from donor’s belly and legs in minimally invasive surgery, and there’s no difference in performance of those cells.

Some cell therapy developers working with MSCs have struggled to limit phenotypic variations in their expanding material. How can you compensate for that problem when you’re expanding the cells? Currently, MSC technology takes advantage of dramatic improvements in two critical aspects: tissue-culture media and reagents. In Europe, we rely on human platelet-based factors in fully humanized cell culture systems, and we’re using certified products that can make MSCs proliferate. When we started in 2005 at laboratory scale, we studied whether we could use platelet lysates to expand MSCs and verified that they worked. Now after 16 years, you can buy those commercially from different providers, and they are cGMP suitable. The quality of those products has improved greatly. So we have excellent platelet lysate formulations that help compensate for the intrinsic variability of MSCs.

Some developers use fetal bovine serum (FBS) for cell expansion. But because of regulatory and performance reasons, FBS is being abandoned. Others use complex cocktails of cytokines in place of platelet lysates optimized for the intended uses, which sometimes makes cell manufacturing a costly challenge. How we feed these cells makes a big difference in their performance. Changing culture media changes their production. From an industrial perspective, we need consistent MSC manufacturing processes that generate a lot of healthy cells in a short time.

To date, no MSC products have been approved in the United States, though some have been approved elsewhere. Why do think US regulators have been slower on the uptake? That’s a deep question touching on different aspects of the MSC community in different ways. Starting with pioneers, Osiris Therapeutics was the first company to work on MSC development in the early 2000s. Mark Pittenger and others founded that company in Baltimore, MD, to verify the therapeutic potential of MSCs. Osiris had a patent and performed early studies while the US academic community was working on MSCs as well. I was a postdoctoral researcher in Memphis, TN, at that time. When the academic community saw a company patenting MSCs, the reaction was not so encouraging: “MSCs cannot be patented; they’re public domain.” However, Osiris was able to move forward but that controversy discouraged early investment in the MSC field while research was still ongoing.

There is also a matter of hype and hope. At the height of ambition, researchers said that we could use MSCs to treat any kind of disease and that the cells were pluripotent. Over time, we’ve come to believe that we have now less on their differentiation and more in their capacity to secrete bioactive molecules focusing on cancer, autoimmune, and skeletal diseases (and a bit less on neurological conditions). The scientific and business communities have realized that not everything that glitters is gold, so to speak.

In the meantime, induced pluripotent stem-cell (iPSC) technologies arose, then the scientific community and founding agencies were jumping on that promising technology. There was a lot of hype there, too, and it brought a second wave of interest in developing progenitor cells. A lot of public funding poured into iPSC research, and a few companies were founded. So the feeling is that even after 20 years, the public–private concerns over MSCs are still at issue, with the US National Institutes of Health (NIH) investing more in iPSCs than in MSCs. We still have a lot to understand about MSC biology for more robust therapeutic products.

In Europe, by contrast, a large amount of money was invested in MSC-based research for orthopedics, kidney disease, and many other fields. That’s why there are more European than US companies working on MSCs. Early public investment generated scientific knowledge that led to start-up companies and now clinical pharmaceuticals made from MSCs. It is a slow process, and it takes time. There is no rushing cell therapy. In China, it is even more advanced. The Chinese government put lots of money into MSC therapies, and the stock market there saw MSCs as a viable therapeutic vehicle. So even more and larger Chinese companies are working on them there.

Even if we still have challenges to make a MSC therapy for large numbers of patients, that illustrates how early science translates to public investment and then the capability of companies to incorporate those investments for public health.

What do you think are the biggest barriers to MSC commercialization? And what will it take to mitigate those challenges? I think that the cost of manufacturing still has to go down. From a European public-health perspective, cell-based products are not cost-effective enough to justify wider use. If you’re living with cancer, then the government will pay for your cell therapy, but if you are living with a quality-of-life issue, then you cannot pay €20,000 for a treatment. Maybe the United States and China have different scenarios, but here we need to keep public healthcare systems in mind. That makes cost reduction very important.

Manufacturing networks are the second key aspect. We need to create a network of current good manufacturing practice (CGMP) facilities that can supply large numbers of patients. If Rigenerand’s product succeeds, then we’ll have to adopt our platform to serve a large population. It’s going to be a technological challenge in terms of upscaling. We are ready to do this with an eye on the final cost of the product.

The third key aspect relates to our interactions with regulators in setting up patient-specific investigations by defining inclusion and exclusion criteria. In some cases, cell/gene therapy products have been given to patients with very advanced diseases, such as very bad rheumatoid arthritis or cancer. That’s fine when you’re still making sure that products are safe, but now that we know they are, why not treat patients with less-severe disease? Disease severity is an obstacle even for promising products. So we need to interact with regulators about identifying less severe patient populations affected by incurable diseases. We cannot just treat cancers that are already metastatic with a single, noncombinatory approach of cells delivering an anticancer agent.

So cost is first, manufacturing is second, and the third part is clinical-trial design based on 20 years of MSC development.

What steps is Rigenerand taking now? We’re proud of what we’ve achieved in under five years, from bringing together an internal expert team to creating a fresh, autologous, gene-modified product. Even 15 years ago, that was unthinkable. In the summer of 2021, we should be able to start our first clinical trials for pancreatic cancer in combination with chemotherapy. This is a unique opportunity to challenge the typical MSC approach and observe the performance of our cell-therapy product. There is great promise for treating other cancer types as well.

Size Matters
Manufacturing continues to be a concern in cell/gene therapy development. A number of companies have focused on their R&D pipelines more than the manufacturing side. Rigenerand is working on both. Over the years, the company has learned much as technologies have advanced. Now it’s presenting as a partner for other companies interested in MSC therapy — Bone Therapeutics in Belgium being among the first. Dominici emphasized the value of experience and knowledge developed over time. That helps in developing solutions as problems arise.

One reason that early MSC efforts failed was that in the past, large pharmaceutical companies have not always been nimble enough to work with cells. Companies often tried to apply their models and development expertise to the radically different cell- therapy field through acquisitions and licensing, but the necessary mindset to bring those things together wasn’t always there. Small innovator companies typically have trouble facing the regulatory hurdles of scaling up. Rigenerand occupies a middle ground, and it may be such midsized organizations with experienced personnel that are best positioned to pave the way toward renewed MSC therapy success.

Brian Gazaille is associate editor of BioProcess International, part of Informa Connect; [email protected]. Massimo Dominici, MD, is director of the oncology department and principal investigator of the cell therapy laboratory at University of Modena and Reggio Emilia, Via Università, 4, 41121 Modena MO, Italy; 39-0594222858; [email protected].