Q&A: Discussing Imsidolimab for Generalized Pustular Psoriasis, With Neal Bhatia, MD

After the acceptance by the US Food and Drug Administration (FDA) of a Biologics License Application (BLA) for imsidolimab in generalized pustular psoriasis (GPP) was announced, the HCPLive editorial team spoke in an interview with a dermatology leader regarding this move’s significance for patients with GPP.1,2

Vanda Pharmaceuticals' investigational interleukin (IL)-36 receptor inhibitor could potentially add to the limited armamentarium of agents implemented within the GPP patient population. The medication is currently under formal review by the agency as a potential addition to the emerging class of IL-36–targeted drugs in the dermatology space.

Neal Bhatia, MD, a dermatologist at Therapeutics Clinical Research whose location served as an investigator site for the development of spesolimab (Spevigo; Boehringer Ingelheim), the first IL-36 receptor inhibitor approved for GPP, spoke in this Q&A interview about this new announcement regarding imsidolimab:

HCPLive: I wanted to ask you a little bit about the FDA’s acceptance of the BLA for imsidolimab and the significance of this move. What might this mean for patients with generalized pustular psoriasis, and how significant would you say it is for clinicians to see another therapy targeting the IL-36 pathway?

Bhatia: I think it's actually very novel and well-timed. We were an investigator site for the Boehringer Ingelheim drug, which is now spesolimab. That was the first IL-36 to make it to dermatology for us, which was great to have another molecule, which is even better, and adds to the significance. Leo Pharma now brings spesolimab map to the market for us and they've done a good job with that. That being said, Vanda makes good drugs, from what I understand. I think this is another one where the GEMINI trials. 53% of the patients got to clear or almost clear by Week 4.

For many of these patients who suffer in a prison of misdiagnosis or just not having options, it is really some game-changing stuff for them. More importantly, we're understanding how rapidly the disease can be mitigated with the onset of the intravenous dosage. We saw that with the Effisayil 2 trials and the Effisayil 1 trial as well, and it brought them both to relevance. The Effisayil 2 trials, specifically with the SubQ to keep things away…I think what imsidolimab is showing us is that it's got a very similar destiny, if you will. Clinically, thinking about durability, the 2-year maintenance period without flares is a significant improvement from what we know from a patient's quality of life standpoint.

My biggest take home point is that I hear a lot about a lot of dermatologists say, ‘Well, my patients got better with a 17 inhibitor or a 23 inhibitor.’ From a psoriasis pathway, there is always a little bit of overlap. What interleukin-17, what IL-23 does, and what some crossovers like IL-22 are involved with is that they're all intermixed into it. There's going to be a little impact from what targeting those cytokines can do. But GPP is well established in an interleukin-36 milieu, where that cytokine is the main driver. You see a lot of neutrophils and a lot of reactive oxygen species, a lot of tissue damage. All of that is unique to the IL-36 pathway, and by inhibiting that, just like we saw with spesolimab, we'll see that with imsidolimab. We can make real headway in keeping the disease away. Not just making it go away.

HCPLive: You mentioned to the 53% of patients attained clear or almost clear skin by Week 4. How meaningful would you say that level of rapid response is for clinicians managing acute GPP flares?

Bhatia: You can look at it from the dermatologist's side as well as the patient's side. Obviously, from the patient side, if they have had no relief of the pain of the visceral symptoms, the fevers, the misery that they go through with the pustules, this will be a godsend for them. I would say that first and foremost, a lot of these patients just live in fear of their next flare. Even when their flare is put out, the first thing they do is worry about when the next one is. Again, that is the nature of the disorder. I think even more so, to see some quick onset of relief, it should take away the thought process of turning to a 17 inhibitor or 23 inhibitor, when that isn't the pathway of choice, and it's not really what we see under the hood for GPP. With the label of psoriasis under generalized pustular psoriasis, there's going to be a mindset that says, ‘Sure, these psoriasis drugs should work.’ But I think we've seen enough data, as well as seen enough mechanism of action discussion, that we know that the inhibition of the 36 pathway is really the key to success for these patients.

HCPLive: From a clinical perspective, how important is the reported durability of response over the roughly 2-year maintenance period with flares in the active treatment arm?

Bhatia: If we can put out the flares and give patients some relief of their potential onset, that's a very significant win for how this drug could impact the market. Understanding 2 years [of maintenance] for patients who have had this disease, you can imagine what that does to quality of life. We talk about quality, like for eczema, psoriasis, and other disorders like hidradenitis, and these are all very significant. But from what we've seen of GPP, we haven't had an option that has really been a benefit. We've seen cyclosporine and some of these other Th1 drugs go after that process, which is incomplete. They're slow-acting, and they come with their own baggage. So, to see where we can get some real relief from what the GEMINI trials showed us, as well as what we can see in the 2-year data, I think we have a lot of opportunities to put out fires that didn't get put out before.

HCPLive: If it is approved by the FDA, where do you think imsidolimab could fit within the current treatment landscape for GPP?

Bhatia: If you look at, you know, spesolimab against the current market-approved treatments, it would probably be side-by-side with that. I would hope that the dermatologists are understanding that that pathway is not the pathway that affects GPP, even though there may be some anecdotal evidence. A lot of dermatologists will say, ‘Oh, sure, my patients do better on 17, 23,’ as I said, and for me, that makes sense, because you have easy access to it. You have easy access to a sample of it to get them started. But if that is the way to get the ball rolling and then get them on an IL-36-modifying treatment, I think that would be a paradigm that would actually make a lot of sense.

HCPLive: Given the rarity and the severity of GPP, how might a therapy with a favorable safety profile and low incidence of anti-drug antibodies influence treatment decision-making in clinical practice?

Bhatia: I think the first key is just making the diagnosis. Get that diagnosis confirmed. I would give the patient their own path report so that they carry it around in case they run into trouble, or they get into an emergency room or urgent care where they can't get treated. They can show whoever has seen them that this is their diagnosis. I think the other key to the equation, too, is to get them to a place where infusion can be as easy as possible, or at least have access to the drug within a day or 2, to try to get them out of the flare.

Really thinking about the big picture for the dermatologist is being an advocate for these patients, saying, ‘Look, this is a rare disease. This is not just a variant of psoriasis that I can try to knock down with other therapies that I have samples of.’ I think even more so, just to support the research as well as the approval of some of these newer therapies and say, ‘Well, we're going to welcome those into dermatology and not give these away to rheumatologists and oncologists.’ Because that's where we lose our edge on our specialty. That would just be a shame.

The quotes contained in this summary were edited for the purposes of clarity.

Bhatia reported serving as an advisor, consultant, and investigator for AbbVie, Almirall, Arcutis Biotherapeutics, Beiersdorf, Biofrontera, Boehringer Ingelheim, Bristol Myers Squibb, Cara Therapeutics, Dermavant Sciences, EPI Health, Ferndale, Galderma, Incyte, ISDIN, Johnson & Johnson, La Roche-Posay, LEO Pharma, Lilly, Ortho Dermatologics, Pfizer, Regeneron Pharmaceuticals, Sanofi, Sun Pharma, and Verrica Pharmaceuticals.

References

1. Smith T. FDA Accepts BLA for Imsidolimab as Generalized Pustular Psoriasis Treatment. HCPLive. February 25, 2026. Accessed April 28, 2026. https://www.hcplive.com/view/fda-accepts-bla-imsidolimab-generalized-pustular-psoriasis-treatment.

2. Vanda Pharmaceuticals Announces FDA Acceptance of Biologics License Application Filing for Imsidolimab for the Treatment of Generalized Pustular Psoriasis. Vanda Pharmaceuticals, Inc. February 25, 2026. Accessed April 28, 2026. https://www.prnewswire.com/news-releases/vanda-pharmaceuticals-announces-fda-acceptance-of-biologics-license-application-filing-for-imsidolimab-for-the-treatment-of-generalized-pustular-psoriasis-302696991.html.