New IL-23 Inhibitor Data Highlights for Psoriasis, With Eingun James Song, MD

A session titled ‘Clear Skin, Clarity in Care: Emerging IL-23 Data Highlights for Psoriasis’ was presented at the 2025 Fall Clinical Dermatology Conference in Las Vegas.1

To discuss some of the data and takeaways from this session on interleukin (IL)-23 inhibition for psoriasis, the HCPLive team spoke with Eingun James Song, MD, one of the session’s presenters. Song emphasized several themes from the talk on new IL-23 inhibitors, including expanding systemic therapy to patients with lower body surface area (BSA) and high-impact areas.

“I'm talking about patients with maybe lower body surface area, or patients that maybe just have high impact areas, but are not being adequately addressed with topicals,” Song explained. “So to really get around some of the limitations that we have with using body surface area as the only measure of disease severity, the [International Psoriasis Council], under the guidance of Dr. Bruce Strober, actually recommended that we recategorize disease severity, move away from just mild or moderate or severe, based on BSA alone, and just simply put patients into two different buckets: Are you a topical patient or a systemic patient?”

Song highlighted the criteria for these 2 categories, noting qualification to receive systemic agents, one needs to have greater than 10% BSA, have a high-impact area affected by psoriasis, or have failed a topical therapy.

“Now the first two criteria are pretty black and white,” Song said. “It's pretty self-explanatory, but it's the third criterion that wasn't as well-defined, because topical failure can mean a lot of different things. Is it because you didn't get better? Is it because you don't like the vehicle? Is it because you just had a hard time being compliant? The IPC recently published its definition of a treatment or a topical treatment failure. According to these guidelines, if you've tried two consecutive four-week courses of a topical therapy, and you fail to get to a body surface area of 1% or less, or a [Physician's Global Assessment] of clear or almost clear, then you should be deemed a topical failure.”

Another theme highlighted in this session at Fall Clinical was that of drug persistence, or what is also known as ‘drug survivability.’ Song described this as a great surrogate for how well a drug works, how well a drug is tolerated, a drug’s safety, but also that it is helpful for insurance coverage and compliance.

“It's a good measure of all of these things combined in one, and we have various different ways that we can do real-world drug persistence studies,” Song said. “Whether that's coming from registries or claims data. We reviewed several of the larger studies that have been done in the space, and what we've seen very consistently is that, number one, patients discontinue their first biologic for all sorts of different reasons. That number could be fairly high, anywhere from maybe 20 to 40% of patients will stop because of inadequate efficacy, safety, tolerability, or sometimes because of insurance reasons.”

What these data sets have shown, Song explained, is that the IL-23 class, whether it's risankizumab or guselkumab, has the highest levels of drug persistence over the course of 3 years. If 1 of these 2 drugs is started, Song noted patients are far more likely to stay on those 2 medications than any other medications for psoriasis.

For any additional information on this topic, view Song’s full interview above.

The quotes contained in this summary were edited for clarity.

Song has reported serving as an investigator, consultant, and/or speaker for AbbVie, Alphyn Biologics, Amgen, Apogee, Arcutis, Bristol Myers Squibb, Boehringer Ingelheim, Dermavant, DermBiont, Galderma, Incyte, Janssen, LEO Pharma, MoonLake, Novartis, Ortho, Pfizer, Regeneron, Sanofi, Sun Pharmaceutical Industries, Timber Pharmaceuticals, and UCB.

References

1. Song E, Del Rosso J, Strober B. Clear Skin, Clarity in Care: Emerging IL-23 Data Highlights for Psoriasis. Session presentation at the 2025 Fall Clinical Dermatology Conference, Las Vegas, Nevada, Oct 23-26, 2025.