Julie A. Parsons, MD Haberfield Endowed Chair in Pediatric Neuromuscular DisordersProfessor of Clinical Pediatrics and NeurologyUniversity of Colorado School of Medicine, Children's Hospital ColoradoAurora, CO, USAHow have programs adapted to the experiences from clinical trials? I'm just looking at SMA because we've had SMA. We've had onasemnogene around for the longest period of time. We want to always confirm a diagnosis and know that the patient is right. We do antibody testing for these disorders prior to delivering the AAV therapies. We have to know that the product that is incredibly expensive is handled appropriately by the institution. Dealing with the pharmacy, making certain that you handle the agent properly, patients need to be pretreated at this point with prednisone, and that really has to happen so that you know that they're ready for treatment, that they don't have any infections prior to treatment.Then we need to monitor and provide medication and follow-up afterwards. As I said, I think this is really, really important to make sure that you're connected well with the patient. If you live in an area as we do, that has a huge catchment area with patients that come from hundreds of miles away, sometimes they need to stay with us for a period of time, so that we can ensure the safety and follow-up of these patients after we deliver gene therapies.Again, a recurring theme is the patients that you're treating who are not in a clinical trial are not the homogeneous, well-selected patients. It's really all actors. The population that you're treating commercially is very different. We're now moving into treating patients with larger body masses and older ages. We don't always know, because those patients haven't really been included in the clinical trials. We don't really know what some of the effects are going to be with that group of patients as well.I am a neurologist. I am not an immunologist. I have had to learn a lot of immunology at this point, but it's still not sufficient. I think that we also need to reach out to our subspecialist colleagues who really do have more experience than we do to try to help us with some of these issues, because as we look at these viral vector capsids and the transgenes, we have to say, is there something that we can do to mitigate the immune response that we're seeing when we're giving massive doses of these agents and really taxing the immune system in our patients?Looking at possibilities, we give steroids, and that's really what we've done. That was what was done in the early clinical trials with MENDEL. It's like, okay, prednisone, that's all we have to do is we give steroids and everybody will be fine. That really isn't maybe the answer. As we have more information, we know that we're going to start with steroids, but we're really going to look at, is there a way to block both the B-cell response, the T-cell response? Is there something that we can do so that we don't have to sit on the edge of our seats and not sleep for months after we treat these patients?At least in a trial, was done looking at patients who were treated just with corticosteroids. Those patients had rapid increases in IgM and IgG. There's complement activation. Both the adaptive and the acute immune responses are triggered. That's really what we're doing as standard practice right now, but in the trial looking at treating patients and pretreating patients with rituximab blocking B cells and sirolimus and corticosteroids, then no significant change in IgM, IgG.Is that something that we should be doing? I think that some of the clinical trials that are being set up are looking at instituting some of these immune-modulating features to see whether or not their outcomes are improved. Can we do anything proactively to prevent our patients from having some of these very severe events or fatalities? I think that's really what we need to be looking at now. I think we are looking at that as a community, and to me, is a story that is still unfolding in terms of how we keep our patients safe.In the next part, Doctors Beggs and Parsons will discuss key issues on gene therapy development.