Q&A: Implications of Ixekizumab, Tirzepatide Data for Psoriasis and PsA, With Mark Lebwohl, MD

New data from the phase 3b TOGETHER-PsO trial continue to spotlight the growing intersection between psoriasis and obesity management.1 These data, showing the improvements in skin clearance and weight reduction with combined ixekizumab (Taltz) and tirzepatide (Zepbound) versus ixekizumab alone, were touched on in a recent interview with Mark Lebwohl, MD, of the Icahn School of Medicine at Mount Sinai.2

The analysis, looking at adults with moderate-to-severe plaque psoriasis and obesity or overweight, demonstrated significantly greater improvements by Week 36 of combination therapy use, with 27.1% of participants on combination therapy attaining both complete skin clearance (PASI 100) and at least 10% weight loss versus 5.8% of patients treated with ixekizumab monotherapy.

In the following segment of Lebwohl’s recent interview with HCPLive regarding his team’s findings, Lebwohl discussed the broader implications of the data for psoriasis care, emphasizing that obesity management should increasingly become part of routine dermatologic treatment strategies. Lebwohl noted the benefits observed of the combination therapy in TOGETHER-PsO may extend beyond ixekizumab specifically.

The following interview with Lebwohl highlights these findings, their potential implications for future psoriasis care models, and the evolving role of weight management therapies in dermatology:

HCPLive: Ixekizumab is currently the only biologic studied in combination with an incretin-based therapy in psoriasis and psoriatic arthritis. What broader implications do these findings have for future research into combination approaches targeting both metabolic disease and inflammatory skin disease?

Lebwohl: There are actually several questions buried in there. First of all, I do think that dermatologists should start adding weight loss drugs to their therapeutic regimens. That's number one. Number two, I think that the results of this can be broadly applied to weight loss drugs and to biologics or other treatments for psoriasis. If you add obesity drugs to our other therapies, they all work better. All you have to do is look at their pivotal trials. The patients who are obese did less well for virtually every treatment we have. There's a third implication in this…they're both anti-inflammatory, but we've not proven that using, for example, an obesity drug by itself will make psoriasis better, although there are studies that have shown that in a less way than what we showed with the combination.

Interestingly, also in some of the myocardial infarction studies, patients who were put on obesity drugs and did not lose weight still had a reduction in heart attacks, and that suggests that the incretins by themselves have an anti-inflammatory effect that helps the psoriasis. We have not proven that, but I think that might be another factor in why the patients get better. It’s still speculative, though.

HCPLive: Current psoriasis guidelines already recommend addressing obesity, but treatment is often still handled in silos. What barriers do you think exist between dermatology and obesity management today, and how might data like TOGETHER-PsO help encourage more integrated care models?

Lebwohl: Yeah, I think it's largely an educational barrier. You know, getting obesity drugs is already complicated because they cost a lot, so a lot of our medicine colleagues also have that problem. You'll explain to a patient, ‘Here's the choice, the drug's really good for you, there are many reasons why you should be on it, but it might cost several $100 a month.’ Mount Sinai, where I work, has a program where, last year, employees who are on incretins paid for the one that we used in the trial, tirzepatide, and paid $150 a month. I said that to one of my patients, who was just doing great, and he said, ‘Huh, you know, I save more than that a month in food.’

He loved the combination, as do almost all the patients. But I think we have to put it in perspective. There's a financial barrier, not just for dermatologists, and they're not going to deal with it any better than the dermatologist is. We are great at getting biologics for our patients. We have a whole team assigned to it. We have step therapy legislation. The problem is the copays on the incretins for the psoriasis biologics. Usually, we can have patient assistance programs, and we can often get the copays waived. But on the incretins, we can't. So the patients know that there's going to be a certain cost to it, and companies have different arrangements…I don't even know the name of the program, but for Eli Lilly, if you're on ixekizumab, you can get tirzepatide less expensively. So I have a lot of my patients on that program, because it's a lower cost.

HCPLive: What do you hope this research will continue to explore? What do you hope is the future of this trial program?

Lebwohl: I think it would be good for us to be able to prove why they lose weight. We're doing a study like that at Mount Sinai as well, looking at the molecular aspects of why the patients have this synergistic effect of the two drugs. That's one piece of it. I think it would be nice to know if indeed the obesity drugs have an anti-inflammatory effect that's adequate, that we should be thinking of them just for that reason, for our psoriasis patients, let alone the weight loss. That's a question that I think will be answered at some point, because it hasn't just occurred to me, it's occurred to many people.

I think changing the way people practice is the biggest piece of this. You know, it can't be a one-shot study, and everybody forgets about it. There will be new psoriasis guidelines coming out. I'm hoping that they will include this information and encourage our colleagues to think about the combination when appropriate. I don't think anybody would doubt that for patients who are overweight or obese, it's appropriate. Many of the insurance companies require that patients have obesity if they're in the BMI range of 27 - 30. They have to be obese and have two comorbidities. Well, psoriasis should be considered one of the obesity-related comorbidities. If you have psoriasis and you're overweight, and let's say your BMI is 27 and not 30, you should be a candidate for these drugs.

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

Disclosures: Boehringer Ingelheim Pharmaceuticals, Incyte Corporation, Genentech USA Inc, Verrica Pharmaceuticals Inc, Pfizer, ER Squibb & Sons LLC, Hexal AG, Takeda Pharmaceuticals USA Inc, Novartis Pharmaceuticals Corporation, AbbVie Inc, Janssen Biotech Inc, Amgen Inc, Celltrion Inc, Almirall LLC, and Incyte Corporation.

References

1. Lilly's Taltz (ixekizumab) and Zepbound (tirzepatide) used together delivered superior efficacy in first-of-its-kind Phase 3b trial for adults with psoriasis and obesity or overweight. Eli Lilly. February 18, 2026. Accessed May 24, 2026. https://investor.lilly.com/news-releases/news-release-details/lillys-taltz-ixekizumab-and-zepbound-tirzepatide-used-together-0.

2. Smith T. Ixekizumab, Tirzepatide Effective Together for Psoriasis and Obesity or Overweight. HCPLive. February 18, 2026. Accessed May 25, 2026. https://www.hcplive.com/view/ixekizumab-tirzepatide-effective-together-psoriasis-obesity-overweight.