We're going to go ahead with two late-breaking abstract presentations. We're going to start with Dr. Steinberg, who's going to talk about two-year safety and clinical outcomes in chronic ischemic stroke patients after implantation of modified bone marrow-derived mesenpical stem cells in a Phase I-IIa study. Easy for you to say. So, thanks a lot for the opportunity to present. I'd like to acknowledge my colleagues at Stanford, UCSF, University of Pittsburgh, and SanBio, the company we collaborated with. Here are my disclosures. So this was the first intracerebral stem cell stroke trial in North America. We published our one-year outcomes almost two years ago, utilized allogeneic bone marrow cells that were placed in culture, transiently transfected with a plasmid for a Notch gene, expanded in culture, cryopreserved, shipped to the site. Two patients supplied enough cells for 18 patients in the study. What does the transient Notch plasmid do? We don't know. It causes differentiation in some way through methylation. The plasmid is lost after several passages of the cell, so it's likely not present during the transplantation into patients. The cells do not have a transformed phenotype. They do not form tumors. How did the cells work? Of course, the initial notion was that they turned into neural progenitor cells, made all the cells in the brain, reconstituted circuits, or maybe that they made endothelial cells, sensor mesenchymal. That's not how they work. They work by pumping out very powerful trophic factors, growth factors, cytokines, molecules and proteins that enhance native mechanisms of recovery, such as endogenous axonal dendritic sprouting, angiogenesis, neurogenesis, gliogenesis, native synaptogenesis, and they have a very powerful effect on inducing immunomodulation. So here are some of the factors they produce, VEGF, BMPs, the usual suspects. The cells do not survive. They're present up to a month. They don't all even survive for a month, at least in rodent and primate models. They're not present later on. It's thought that they are phagocytized by activated microglia. This is how we did this study. It was a dose escalation from 2.5 to 10 million cells done at Stanford and University of Pittsburgh. Patients had chronic stroke. They had a frame put on. The cells were transplanted stereotactically around the stroke into the subcortical stroke, not in the stroke itself since that's a very inhospitable region for survival, even transiently. The patients were 33 to 75 years old, and they were usually one to three years out from stroke. You knew they weren't going to recover. They had modified Rankin scores of three or four in order to get in, NIH score greater than seven. Primary endpoint was safety, and I'm now presenting our two-year post-implantation follow-up. We also had a European stroke scale at six months as an efficacy outcome and a number of secondary outcomes. Here's what the strokes looked like. Patients had to have a subcortical stroke, but most of them also had a cortical stroke, which we did not target. It was done through a single burr hole about the size of a nickel, three passes with a needle, five deposits through each needle pass. Patients were sedated but not intubated. They went home the next day in all cases. Here were our adverse effects. Not surprisingly, most of the patients had headache related to the procedure. Some had nausea and vomiting, 22% of depression or muscle spasticity. Fatigue was fatigue, UTI, constipation, pain in the extremities, C-reactive protein increase or increased glucose in about 17% of patients. None of these were dose-limiting, no deaths. None were probably or definitely related to the cells. Many were related to the procedure. Most of these were mild or moderate. The serious adverse events, which are defined by requiring hospitalization, were the following. There was one seizure 70 days after the transplant. Not clear if that was due to the transplant or not, since these stroke patients do have seizures, but we said it was related to the procedure. One asymptomatic subdural hygroma, hematoma I drained, even though it was asymptomatic. A pneumonia, stenting of a cervical carotid, obviously not related. One patient had UTI sepsis and one TIA that occurred 11 months out. In year two, there was one patient with paresthesias and dysphagia. None of the patients withdrew. All of these adverse events resolved without sequela. Again, none related to the cells and no correlation between these and the cell dose. There were no meaningful changes from baseline in plasma levels of cytokines, antibody levels, to the cell antigens, peripheral blood mononuclear counterimmune function, or other biochemical parameters. So we found it was safe, even up to two years. We were still quite surprised, as I mentioned before, at the improvement. These are patients' scores on the different scales related to their baseline, since they were stable and not recovering. They'd all been through rehab. The patients as a group tended to increase within the first month, statistically significant, increased up to three months. Then at six months of primary outcome, still significantly significant. Sustained at one year, and now we know it sustained at two years on all the scales. NIH score as well, Fugl-Meyer motor and Fugl-Meyer total scores. And if we look at the Fugl-Meyer motor, where 10% improvement or 10-point change is considered clinically meaningful, that signifies the patient's life is altered in a positive way. Seventy-two percent of the patients achieved this clinically meaningful recovery, mostly early on again. You can see here that for the patients with a clinically meaningful recovery, they achieved this usually within three months here. For the patients who did not achieve this clinically meaningful recovery, that was a minority of patients, they recovered later, and it was not sustained. The cell dose did not show any clear dose response with clinical outcome, and there was no association between the improvement and outcome measures and either the baseline stroke or, surprisingly, the patient's age. We had 70-year-old patients who recovered well. Here's a patient before surgery, two years out from a left middle cervical stroke, and she could not move her hands. She could not walk well. She didn't want to get married because she said she'd be embarrassed walking down the aisle, and you could barely understand her speech. It was so dysarthric, and she had an expressive aphasia. That's not advanced. Oh, sorry. Here she is two and a half months later. That's her brother. And here she is four and a half years later. She actually was presenting an award to me at the Smithsonian Institute. For two years after that, I was unable to say more than 20 words. I couldn't move my right arm more than a few inches and could only walk for five minutes without needing a wheelchair. It's been four and a half years to the day now, and I'm able to climb stairs, have conversations with family and friends. I run. I work out. My life is amazing. I was also able to become a mother. So here's what her stroke looked like before surgery. This is the deep stroke. She had a cortical stroke. This is a higher level of flare image, T2 flare. One day after surgery, no difference at the higher level, except there's a little blood in this sulcus. One week later, there's a dramatic change. There's a new T2 flare lesion in the premotor cortex, DWI negative. It's not a new stroke. This resolved by two months, never reappears, yet she's better. And, in fact, 14 of the 18 patients had this new transient T2 flare lesion, primarily in the premotor cortex, appears early on, resolves, never comes back, yet the patients are better. In fact, there's a very significant correlation between the size of this transient initial post-transplant flare signal and neurologic recovery at 12 months on all the scales and at 24 months on these two scales. So we're quite interested, actually, in studying that. And I can talk to people after about what we're doing to study that in the laboratory. We think it's quite an important finding. So what have we learned? This is safe and feasible. Patients did show recovery. It's a small number of patients, no controls. But I think the main lesson is that, contrary to our prior notion, these circuits are not dead or irreversibly injured in chronic stroke. We thought patients recover up to six months and then there's virtually no recovery. That's not true. They can recover years later, may have implications for treating traumatic brain injury, spinal cord injury, and even neurodegenerative diseases. We're still trying to figure out the mechanisms. I think that stem cell transplant for stroke holds great promise. We don't want to oversell it, but it's early stages still. We need to resolve some of these fundamental issues. These findings, at one year, led us to complete a Phase II study, 156 patients. This is a multi-center study throughout the U.S., started a year ago. Sorry, started two years ago. All the patients have now been treated. It's double blind with one-third of the patients getting a burr hole but not the needle. Only the OR personnel know what the treatment was. We'll know in a year when the results are analyzed how the patients do. We just completed also a Phase II chronic traumatic brain injury study with the same cells. I wanted to thank everyone at Stanford on our cerebrovascular team, which I think is responsible for the success of our program in general, and thank my colleagues at Stanford, again, University of Pittsburgh, UCSF, and SanBio. Thanks very much for your attention. Thank you. Thank you, Dr. Steinberg. Are there any questions while the next speaker is coming up? Do you see any kind of immune response? We didn't see it in peripheral blood parameters, but I think that this flare lesion is an immune response, and I think it's a beneficial immune response. I think somehow this inflammatory response is actually de-inhibiting, disinhibiting the circuits that are suppressed. I think there's chronic inhibition of circuits that are still viable, and I think that this somehow jumpstarts them. So I'll tell you preliminarily, we just submitted an NIH grant for this, but our pilot data in animals shows that this flare lesion, which was hard to reproduce, but we've reproduced it, does have an inflammatory component. We've shown that with PET imaging and with immunocytic chemistry, and so we're studying that in more detail now, actually. And I'll tell you another interesting thing, because people think it may be just the needle that is causing this, like a lesion effect. The needle alone with injection of buffer in animals does not cause the flare lesion, but only with the cells.

video presentation

Phase I-IIa study

chronic ischemic stroke

mesenchymal stem cells

safety and clinical outcomes