“What is Ex Vivo Gene Therapy, and What Regulatory Challenges do Developers Face?” Featuring Robert Kutner
Using your own cells to help you heal isn’t science fiction anymore. Today, we’re diving deep into the exciting world of ex vivo cell therapy with Robert Kutner of Biologics Consulting, exploring exactly what ex vivo cell therapy is, how it helps fight rare diseases and cancer, and the regulatory disadvantages that producers face.
Transcript
James: Remove cells from your body, change them to fight a disease and then put them back into you. Now, that might sound like science fiction, but ex vivo cell therapy is fact, and we’re gonna learn more about it with Robert Kutner. This is Insight at Biologics.
Hi, Robert. Before we get in depth on ex vivo cell therapy, why don’t you tell them a little bit about your background?
Robert: Hi. Thank you, James. Yes, I’m a trained chemist. My background in my early days, I originally joined Louisiana State University’s Vector core facility, developing bio vectors for the university systems and provided these vectors for other institutions around the nation. There were not too many vector facilities at that time, so we were able to gain a lot of experience and practice in developing these materials.
And over my time there, I became the director of that core facility and had developed scalable processes for lentiviral vector manufacturing. We had published on those procedures and I was recruited out of Louisiana and brought up to the Boston, Massachusetts area to work in the industry.
There I gained a lot more exposure into the cell therapy side of the practices with the industry kind of growing into that space. I had joined Bluebird bio and there we had an ex vivo gene therapy program intended to target rare diseases. And the goal was to scale up their vector production processes to conform to what is needed in the cell therapy and following those exercises, we were able to successfully demonstrate production of these vectors and cell therapies for these diseases. And they’ve recently gotten approval in those fashions.
So with a few more stints in the industry, I have found myself here at Biologics Consulting ready to kind of speak about these past experiences and what the details are with cell and gene therapy, and what my general impressions are of them.
James: Well, we’re glad to have you here at Biologics and I was very fascinated when we were preparing for this episode to delve into this. So if you would just in general, generally explain ex vivo cell therapy.
Robert: Yes. Thank you. The ex vivo cell therapy in a general sense is a patient goes to a center where they’ll have their blood cells collected, and then those cells are sent to a facility where they’ll be manufactured in some format to be processed. And then re-delivered to, typically a doctor’s office or something, and then those cells are reinfused.
And so the components of the manufacturing, the steps in between the office visits, that’s where the heart of the matter of the activities go. And so, the nature of how a cell therapy can be developed or produced, comes with many different facets in that manner. In a general sense, one, let’s say without a gene therapy involved during the ex vivo procedures would typically use a recombinant protein and introduce that to the cells during the processing, and allow that introduction to be the manipulation of the cells.
And then in turn, that manipulated ex vivo cell now has a property that should provide efficacy when provided back into the patient. A good example, one of the early approvals was Provenge, which was using a chimeric antigen basically for a prostate cancer antigen. And that chimeric antigen was introduced to the patient’s cells.
It was an autologous therapy and the patients who had a diagnosed cancer, that fit the criteria for this treatment, would basically go to the doctor’s office or the patient’s collection center. Then in that case they have a leukapheresis in that manner, they would collect a number of cells. Half of them are T-cells, a quarter of them are about monocytes, et cetera.
Those are shipped over to the manufacturing facility. And then it was a two to three day process of what they had to do. But basically they purified the cells while introducing them to that chimeric antigen. And then in turn, once the cells were fully activated, they were able to be reintroduced back into that patient and then in turn that cell basically could activate the T-cells and the efficacy, the mechanism of action they’re looking for in that setting. And so, kind of giving an example, a general one in that setting with recombinant proteins used but recombinant proteins don’t always have to be used. It could be just a general manipulation.
James: Okay, now, again, because I am not a scientist, I just wanted to make sure I understood one teeny weeny thing. I’m sure people who do what you do understand, but I wanna make sure I understand it. The reason that blood cells are used is because of how easily they can be reintroduced into the host organism, correct?
Robert: Yes. Great question. It’s an easy target for collecting cells to get a suitable mass that could be corrected and then reintroduced back into the patient in a suitable manner, going right back into the bloodstream. There’s other compartments within the bloodstream that can be accessed, such as mobilizing stem cells with certain reagents, and then in turn you can enrich those cells out of the bloodstream. And so it’s not the only way. I, as an example, brought in the blood cells, but certainly there are other practices that are being developed and it is important to note that what we’re talking about are regulated practices.
There are some practices that are starting to pop up that are not regulated with stem cells and their natures of how they harvest cells and reintroduce them are not what we’re talking about here. We’re talking about, specifically, those regulated environments where they’re controlled as a device and or as a reagent or drug substrate that would be coming in to manipulate the cells. It’s all communicated under the agency’s guidelines.
James: Okay. All right. So you were mentioning gene therapy in conjunction with the ex vivo product. How do you incorporate gene therapy into the ex vivo product?
Robert: Yes, this is, this is where it gets complicated, James, because the example I’d given you previously we’re talking about just a recombinant protein and that particular protein has to be manufactured, and that’s a typical manufacturing process that uses whatever cells to scale up and produce a protein that can be purified. That practice for production of proteins has been well established, and so, very suitable.
When it comes to ex vivo gene therapy, instead of that chimeric protein that was used in Provenge, a viral vector comes in. So the production of that viral vector is now its own set of materials that need to be accounted for, in regards towards providing the agent from manipulating the cells to properly get the efficacy downstream. And continuing with that, the nature of those materials that are involved with a viral vector to be produced is basically its own drug in a sense.
There are a lot of therapies out there that just use viral vectors as a direct therapeutic and the filing associated with putting together these materials to communicate to the agency won’t have any differences. It would look just like its own drug filing for that vector, just as much as the whole filing for the cell product that is manipulated looks like a drug filing too, and so there’s multiple filings that kind of occur within one cell therapy.
Same thing occurred with Provenge in there, a recombinant protein. It was a very substantial package that kind of demonstrated what was occurring, but ultimately, the manipulation that is happening with the gene therapy vector, which has its complications in itself to be manufactured, is allowing for an actual genetic manipulation of those cells prior to reintroducing them back into the patient.
And so this attribute allows for targeting rare diseases and genetic monogenic diseases that are not accessible, such as with that therapeutic approach that Provenge was using and a rare disease. There’s a mutation in the genome that can be corrected and usually that mutation manifests some sort of blood disorder.
That’s why we have a lot of blood treatments for cell therapies at this stage because they’re, as you had brought up, easier to access and modify and then reintroduce. And so in turn, the rare diseases and now, what’s come about too is, cancer treatments, oncology, with CAR-T therapies and such for the same principles. It’s just manipulating for a different approach as opposed to a rare disease.
James: Okay. Now you had mentioned complications in the process. Are there regulatory complications around drug substances and drug products for an ex vivo product?
Robert: Yeah, there, it’s not just regulatory. There’s industrial also to that capacity, but overall, there’s just a number of complications when you bring in multiple types of products. You have subject matter experts that are well versed in cells. And then also the additional need for subject matter experts and vectors, or the particular vector that may be utilized in that sense. And then being able to communicate those two particular components individually to the agency. And then also have the overall communication sync up and be able to have that message come across clearly.
And this is just kind of inherent with this product, with a cell therapy product because a material such as a therapeutic for a rare disease and then a therapeutic for a cancer oncology have two different medical teams that need to support that clinical side of the therapy. And so having that clinical support is on the industrial side too, that needs to be involved and grown with the company in that sense.
So when the company has multiple products and pipelines across different indications, the nature of not only the target therapeutics, but also the drug substances and drug products that are being manufactured, just provide a number of complications. All that can be overcome is just being aware of them ahead of time and knowing what the situation is that one is walking into.
James: Okay. All right. So if you would describe how a campaign for ex vivo gene therapy would go from the initial discovery through the development of a product.
Robert: Yeah, that’s an interesting thing. There’s so many different ways. It’s kind of come about over time, because when I first started in the industry, there were not too many cell therapies available to reference from in that sense. And so, the approaches that could be developed were much more in the earlier phases of the discovery in regards to the academic setting in that situation.
Where we are today, it’s a lot more industrialized in that capacity. The discovery kind of happens not only in academia, but also within the industry. But the processes don’t change, it’s just a matter of how that occurs. And, overall a concept or some sort of efficacy is able to be determined early on in some animal model or even a cell model per se, to be able to kind of show some sort of phenotypic correction that then enables a product to begin to do its development.
Through a discovery, which again, this can be sliced in many different ways. I’m talking about a particular cell therapy product that may have [a road to?] GMP. The nature of the whole process to manufacture that cell product is what needs to be demonstrated initially. So what one would ideally do is, lock down their materials and their processes, for both the vector and the cells that will be manipulated prior to the reintroduction into the patient.
Then with that established process, develop a initial results set and then that result set should be able to demonstrate a suitable capability to do an engineering run something in the clean room, to that end, and I’m not saying that there’s not more steps in between, but in an idealized setting, a second run would happen closer to the GMP setting because the goal is to establish process history that then allows for the results that we do get in the GMP facility to be understood because we’ve already demonstrated our process and these materials in that process over these previous productions, over that development run, over that engineering run.
Ideally you have two to three runs, maybe on each, but a total of three going into one’s GMP production, and then that allows for a very suitable batch record that can be used to consistently manufacture the product, both again, the vector and the cell products. And what I’m not going into is the number of facilities that may be involved in such a setting because the vector production would occur, likely in one facility, or at least in a different setting than where the cell therapy or the cell manipulation would be occurring.
And so to that end, the whole process can still be demonstrated and provided, but you want to capture all of those components in that original set of studies through as much as possible so GMP can be demonstrated, and that’s what it would look like to have something coming into production and completing a GMP production ready for a cell therapy trial to that manner.
And again, it’s just a matter of how the target disease indication is needing to be understood, kind of defines the assays around the material and both the vector and in the cell therapies. But you also want to recapitulate all those assays and the like that you would use to release your material to show suitability for disposition and use in some of the clinical trials.
James: Now we’re talking about production and in pretty much all areas of technology these days, one of the things that they’re seeking is scalability. Is there an ongoing attempt or issue with scalability where ex vivo gene therapy is concerned?
Robert: Scalability? It has its place case by case. I could say in that sense, again, early on, there were not too many technologies available to facilitate any type of mass introduction of these types of cell therapies, and so what we were doing were manual manipulations and GMP settings and the like, and the nature of scaling that process requires numbers of operators and more of a larger footprint per se.
But technologies have come a long way since then, and not only in the capabilities to manipulate cells, but also in the ability to do the particular gene therapy in a sense. I think in today’s setting, there is a case by case environment because some individuals or companies per se have technologies that require very little manipulation, which allows for a lot more scalability in that context, where another therapeutic, it could be a completely different indication, would require a different level of scalability that today’s tech might not be there for.
And so, the nature of what a company has to contend with is much more on their own as far as what their technology is trying to get towards and in general, the expectation should be that they could deliver on the indication’s clinical need upon approval. And so being able to achieve that generally with a cell or gene therapy does require a lot more labor and capital in that sense because of, as I described all through the amount of steps and manipulations, shippings of the materials testing development to prepare and just demonstrate GMP capabilities, et cetera.
So those costs get brought into the overall nature of what’s occurring, but that also kind of carries through to what is scalable. It’s important to be very cognizant of those activities early on and how they will scale. Cause scaling’s where there’s a lot more negativity in the field. We haven’t had that many approved products and things are just starting to scale, and I think the nature of supplies and the like, are gonna be challenges to understand as we go forward, too.
James: And so Robert, if somebody is just beginning to get into this, Biologics and your team can help with that, correct?
Robert: Yes, that’s what the CMC business unit provides. It’s a very diverse group that has all kinds of experiences, I couldn’t even begin to list them all. I, as I’ve mentioned earlier, joined recently and I’m just meeting everybody initially as we go through different projects and just the level of and depth of knowledge, not only, here I come in with this cell and gene therapy experience, but around their recombinant proteins and vaccines and medical devices, et cetera.
It’s just something that allows for a more facile development of a cell therapy, because having access to potential consultants that have their experiences that can then also provide support for whatever development campaigns a company or an interest may be going towards, I would have to say that there’s a lot to be provided with this skill set here at Biologics Consulting.
James: Thank you to Robert Kutner for joining us. And if you’d like more information, just email us at insight@biologicsconsulting.com. That’s Insight, @ Biologics Consulting, all one word, .com. Also, we’d love it if you’d like, subscribe to, and rate and review our show.
The executive producer of Insight at Biologics is Kris Kraihanzel. This episode is produced and edited by James C. Taylor, technical supervisor is Jeff Weis. The Insight at Biologics theme is by Tom Rory Parsons. I’m James C. Taylor. Thank you for joining us. Please come back for more Insight at Biologics.
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