There are already well-functioning therapies for erectile dysfunction – so why do we still need new approaches? Because so far, it’s all about treating symptoms, not curing them. Here’s how that could change.
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DocCheck: Welcome to this DocCheck News interview on erectile dysfunction. Specifically, we would like to talk about injectable therapies in erectile dysfunction. And our expert on this topic is Mikkel Fode, a professor of neurology at Copenhagen University Health and Care and Chester Hospital and chairman of the Scientific Committee of the European Society of Sexual Medicine. Welcome.
Prof. Mikkel Fode: Thank you.
DocCheck: Given PDE5 inhibitors are an undisputable success in erectile dysfunction therapy, why do we still have to talk about new therapies for ED?
Fode: I think that’s a great question. The PDE5 inhibitors certainly are difficult competitors. Already, when the PDE5 inhibitors came out, there were studies done that showed that the number one desire from patients with erectile dysfunction was an actual cure. And with the treatments we have now, including PDE5 inhibitors, there is no cure. You have to keep taking the medication. So, what we’re really talking about is regenerative medicine and ways of regaining erectile dysfunction without continuous treatment. That’s why we’re talking about it. It’s really the Holy Grail in treatment of erectile dysfunction.
DocCheck: You’re part of a discussion session of this year’s European Association of Urology Conference in Milano on regenerative injectables for erectile dysfunction. This is a topic you’ve recently published on. What kind of therapy are we actually talking about when you talk about this retractable? Can you summarize in a few sentences what this actually is?
Fode: Yeah, basically it’s two different things. We have injections with stem cells containing spirits. So it’s stem cell therapy, where the hope is that the stem cells are going to go into the penis and regenerate the tissue, differentiate into especially smooth muscle cells. And then we have something called platelet rich plasma, where the idea is that the platelets in the plasma of the patient himself contain a lot of growth factors.
So, if you inject that into the penis, then these growth factors will be released and cause regeneration of the tissue, smooth muscle and blood vessels especially.
DocCheck: Okay – and this is also the difference to other injectable therapies that do exist or ideas that have been in existence for years. But this is a completely different way of working, right?
Fode: Yeah, the injectables that are in clinical practice now and have proven to work are completely different. You had to use those on-demand, meaning right before you want the erection. And they basically relax the smooth muscle and the blood vessels. It’s a one time treatment – that’s completely different.
DocCheck: You mentioned possible mechanisms already. How do these new injectables, these regenerative therapies actually work? Can you tell us about what is already known and what is not known?
Fode: There are a lot of animal studies that show, that when stem cells get into the penis, they might differentiate into smooth muscle. One of the problems in ED can be that the smooth muscle in the penis that expands with an erection is replaced by fibrotic tissue, which cannot expand.
So, basically the idea is to have the smooth muscle back by these stem cells. That might also cause a generation of blood vessels and nerve fibers for the platelet rich plasma. We only have a couple of animal studies and they look at nerve regeneration specifically. Those are rat studies where the rats have undergone a crushing of the nerves that are responsible for inducing erections. The idea is that these growth factors, that are released, will cause regeneration of the crash, nerves that would relate specifically to patients with severe diabetes or patients having undergone pelvic surgery such as a prostatectomy. There’s hope that this platelet rich plasma, these growth factors also regenerate smooth muscle tissue like we hope that the stem cells do. But the proof or the studies are animal based.
DocCheck: Let’s talk about these stem cells. Now, you take them from the adipose tissue of the patients themselves. These are not external stem cells, this is not external tissue, but patient derived tissue.
Fode: Well, actually, stem cells have been investigated for ED for more than ten years now and there’s no consensus on this. You can get stem cells from bone marrow or from placental tissue, from fetal tissue, from umbilical cord blood. You can get them from the adipose tissue of somebody else or from the patient themselves. There are a lot of places to get stem cells and there’s no consensus of what’s best after more than ten years of research. But I think we’re moving more and more into taking cells from the patient. Likely there’s less risk of doing this, and it’s also easier to get permission to do it.
DocCheck: Let’s talk about numbers. What is the actual clinical evidence for this kind of therapy? Of course, there’s a lot of animal data, no doubt. But what is out there clinically?
Fode: There’s very little clinical evidence of these treatments so far. For the stem cells, we have about ten clinical studies where stem cells have been given to two small numbers of men and we’ve looked at the erections. Also, in my own study, we’ve looked at erections afterwards. But it’s important to say that for all of these studies, the main outcome has been feasibility and safety and there’s been basically no control groups. And we know that there is a placebo effect in treatment of erectile dysfunction. So the clinical evidence in stem cells is very, very limited. For platelet rich plasma, it’s a little bit different and we don’t have a lot of the case series where all of the patients have gotten the platelet rich plasma. But we have two randomized controlled trials that both seem to show a positive effect.
And I think that we are very, very early. Overall, there are few patients included in these two trials. They do have some drawbacks. And what we see is an effect that’s about a third of the effect that we see with a PDE5 inhibitor such as Sildenafil. So, the clinical evidence is limited and the effect is not very large in the studies we’ve seen so far.
DocCheck: There are bigger trials underway with a proper control group like, for example, placebo injections. This could be done in principle.
Fode: Yeah. As I said, there are a couple of trials already with placebo injections that seem to indicate that there might be a positive effect and there are certainly more trials coming. But I think we need to acknowledge that these treatments have already made it into clinical practice and they’re offered in many places over the world with a lot of promise given and at quite high cost for the patients. I think that’s very early considering that we don’t have the trials and I think we are racing to produce good clinical trials and good clinical evidence against this actually getting into clinical practice. Therefore, we really need these trials right now.
DocCheck: Final question, would you recommend this to a patient who is desperate about erectile dysfunction and who doesn’t get along with the PDE5 inhibitors?
Fode: That’s a no from me, not in clinical practice right now. I’d recommend these patients to be included in the trial if they’re really interested. But I think this is the time for trials, not for stem cells or platelet rich plasma in the clinic. It’s too early right now.
TL;DR generated with ChatGPT
DocCheck News interviewed Professor Mikkel Fode, a neurology professor at Copenhagen University, on injectable therapies for erectile dysfunction (ED). Fode states that PDE5 inhibitors are difficult competitors, and that ED patients want a cure, which current treatments cannot provide. Fode discusses stem cell therapy and platelet rich plasma, which could regenerate the tissue and muscles in the penis and lead to a possible cure for ED. He highlights that the clinical evidence of these treatments is very limited.
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