Ruth Ann Vleugels, MD, MPH, MBA

Ruth Ann Vleugels, MD, MPH, MBA, associate professor of dermatology at Harvard Medical School, spoke with 

 looking at the use of investigational IL-13 inhibitor zumilokibart (APG777) in adults with moderate-to-severe 

The phase 2 trial met its primary endpoint of EASI-75 at Week 16 and demonstrated strong results across several higher-threshold efficacy measures, including EASI-90 and Investigator's Global Assessment (IGA) 0/1 responses. In an interview with 

, Vleugels reviewed the clinical significance of these efficacy and safety data, including outcomes suggesting the drug’s very low disease activity results, a measure incorporating both skin clearance and itch control. Vleugels also discussed the established safety profile associated with IL-13 pathway inhibition, the importance of reduced injection frequency for patients, and other key questions:

 What stands out most to you about the efficacy results seen with zumilokibart in the APEX Part B trial?

 Yeah, thanks for that excellent question. I've actually been very excited about this therapy for a while. I've been kind of tracking its progress. So these recent results are very exciting to me, because essentially, not only did it meet its primary endpoint, which is EASI-75, but actually it performed extremely well on higher efficacy endpoints. When we think about the EASI-90 and the IGA-01, which means clear or almost clear skin, this actually numerically was ten to even fifteen points higher than other biologic therapies that we currently have access to. So, I think the efficacy data is extremely meaningful. We know from previous data that even past the initial 16 weeks, there's additional improvement on this therapy. Hence, the efficacy data is quite robust and exciting to those of us who take care of patients with atopic dermatitis.

 How clinically meaningful is the very low disease activity (vLDA) endpoint for dermatologists managing moderate-to-severe atopic dermatitis?

I actually think this is a really important endpoint for our patients, and really this reminds us that many of our patients who reach the primary endpoint of a lot of our atopic dermatitis studies still actually have active disease; they have itch, etc. We really want to reach for these higher-level endpoints. To date, the therapies that have been most effective at reaching those are JAK inhibitors, which are highly effective.

However, many of my clinician colleagues feel challenged in prescribing these, given their boxed warning for various entities, including blood clots, cancer, and cardiac events, and despite the fact that they are effective therapies, there can be some challenges in having providers write for these medications. To have a biologic medication that can reach these higher-level endpoints is very meaningful, because really these are the endpoints that we're striving for for our patients who suffer from this condition.

Zumilokibart’s safety findings were generally consistent with other IL-13 inhibitors, including conjunctivitis events. How should clinicians interpret these safety data when considering future use of this therapy?

We're very fortunate because we know a lot about this class of medications, and we have a lot of experience with this class from prescriptions of other medications in this IL-4, IL-13 class. So, you're absolutely correct that conjunctivitis is the side effect that we have to think about. Given that I'm an expert in inflammatory skin disease, I always feel pretty spoiled when the main side effect I get to discuss is conjunctivitis. A few important things to remind ourselves are that our atopic dermatitis patients are at risk for conjunctivitis at baseline. Here we're talking about non-infectious conjunctivitis. The vast majority of patients for whom we prescribe a medication in this class, if they do get conjunctivitis, which is usually on the order of about 10% of patients, based on our trial data, we're usually able to either not treat that, or…actually treat it with over-the-counter eye drops, etc.

Occasionally, patients need more intervention, but that is quite rare. So my dermatology colleagues are very comfortable with this class of medication. I think one of the most important things is that the safety profile of this category of medications is that it’s very clean, and it's something that dermatologists and our APP colleagues feel very comfortable with prescribing. Thankfully, the data presented in this recent study highlight that, and this is something that we're used to managing. The conjunctivitis cases were short-lived and didn't require treatment discontinuation. I think that's really important, because we can still think of this category as extremely safe for our patients, and something that my colleagues are going to reach for to care for patients with eczema.

The study highlighted less frequent dosing compared with some currently available biologics. How important is dosing convenience when selecting therapies for patients with atopic dermatitis?

This is really important, and we've learned from our psoriasis patient populations over the last fifteen to twenty years that dosing frequency actually really matters to patients. When we can get a therapy that is a self-injected medicine, and we can reduce the number of injections, this is something that's important to our patients.

So, what's really nice about the data we just saw is that for zumilokibart, during the initial induction or initial 16 weeks, there's over a 50% reduction in the injection days. Then in maintenance, actually, there's an even more substantial reduction. The maintenance data would suggest that patients would need to self-inject two to four times a year, and compared to dupilumab, for example, that would be 26 times a year. That is a very impressive dose reduction in terms of those injections, and again, we know that that's meaningful based on our experience with our psoriasis patients. [We know] our patients are really hoping for therapies that are highly effective, but they don't have to give as frequently.

As zumilokibart moves toward phase 3 development, what additional questions or long-term data would you most like to see addressed?

Yeah, I think that's an excellent question. I feel very spoiled that the data that's come out so far about this agent has really matched and then even exceeded the expectations of the atopic dermatitis community. We're very, very excited for phase three, and thankfully, in atopic dermatitis, most often there's actually good correlation between phase two and phase three results. We're very hopeful that the phase three will be quite positive, because of course, what we're really hoping for again is that our field has been really needing a biologic therapy that is highly efficacious and reaching some of those higher-level efficacy endpoints, while at the same time reducing the injection burden for our patients.

You know that's really what I'm going to be looking for, and of course, as always in phase three, we look for safety. But thankfully, because this mechanism is extremely tried and true, we would expect the side effect profile to be very reassuring and in line with what we see from phase two and from our other phase three studies with this class of medications.

Disclosures: Vleugels previously reported serving as a principal investigator and/or consultant for Pfizer, AstraZeneca, Apogee, Priovant, BMS, Lilly, and Johnson & Johnson.

Apogee Therapeutics Announces Positive 16-Week Part B Induction Dose Optimization Results from Phase 2 APEX Trial of Zumilokibart in Moderate-to-Severe Atopic Dermatitis. Apogee Therapeutics. May 27, 2026. Accessed June 5 , 2026. 

https://investors.apogeetherapeutics.com/news-releases/news-release-details/apogee-therapeutics-announces-positive-16-week-part-b-induction

Smith T. APEX: Positive 16-Week Data Released on Zumilokibart for Atopic Dermatitis. HCPLive. May 27, 2026. Accessed June 5, 2026. 

https://www.hcplive.com/view/apex-positive-16-week-data-released-zumilokibart-atopic-dermatitis

Articles

Phase 2 APEX Part B data for the investigational IL-13 inhibitor zumilokibart in moderate-to-severe atopic dermatitis showed Week 16 EASI-75 achievement with notably strong higher-threshold responses (EASI-90; IGA 0/1), numerically exceeding available biologics in this class. Emphasis was placed on very low disease activity as a clinically relevant composite of skin clearance and itch control, potentially approaching outcomes often associated with JAK inhibition. Safety aligned with established IL-13 pathway experience, with generally manageable, non-infectious conjunctivitis. Reduced injection frequency may materially improve adherence and patient preference.

Vleugels discusses Part B findings on investigational IL-13 inhibitor zumilokibart (APG777) in adult patients with moderate-to-severe atopic dermatitis.

Q&A: Zumilokibart Effective for Atopic Dermatitis, With Ruth Ann Vleugels, MD, MPH, MBA

Discussing Zumilokibart Data in Atopic Dermatitis, With Ruth Ann Vleugels, MD, MPH, MBA

team, Ruth Ann Vleugels, MD, MPH, MBA, spoke about her team’s newly released 

 assessing the use of investigational IL-13 inhibitor zumilokibart (APG777) in adults with moderate-to-severe 

, noting what she described as notably strong efficacy results paired with a familiar and reassuring safety profile.

In her discussion, Vleugels said the data stood out not only because the study attained its primary endpoint of EASI-75 at the 16-week mark, but because several higher-threshold efficacy measures exceeded investigators’ expectations. She pointed specifically to the rates of EASI-90 and Investigator’s Global Assessment (IGA) 0/1 responses, noting that the numerical improvements appeared meaningfully higher than those seen historically with currently available biologic agents for atopic dermatitis. Vleugels also emphasized that earlier findings with the therapy suggest responses may continue to deepen beyond the initial 16-week induction period.

“[We] know from previous data that even past the initial 16 weeks there's additional improvement on this therapy, so the efficacy data is quite robust and exciting to those of us who take care of patients with atopic dermatitis,” she explained.

One of the most clinically meaningful findings, according to Vleugels, was the proportion of patients achieving very low disease activity (vLDA), a composite endpoint incorporating both skin clearance and itch control. Vleugels noted many individuals classified as treatment successes under traditional endpoints still experience residual symptoms, particularly pruritus, underscoring why clinicians increasingly view more stringent disease-control targets as needed.

Vleugels contrasted these outcomes with the efficacy profile of JAK inhibitors, which she acknowledged can achieve similarly high-level responses but may create hesitation among some clinicians because of boxed safety warnings involving cardiovascular events, malignancy, and thrombosis risk. In that context, she said a biologic capable of reaching comparable efficacy benchmarks could represent an important advancement for clinicians seeking highly effective options with a more established safety profile.

Regarding tolerability, Vleugels noted that the adverse event (AE) profile observed with zumilokibart aligned with prior experience using IL-4 and IL-13 pathway inhibitors. She characterized conjunctivitis, the most discussed adverse event in this therapeutic class, as generally manageable, often mild, and rarely severe enough to require discontinuation.

She also highlighted the therapy’s reduced injection frequency as a potentially important differentiator. According to Vleugels, maintenance dosing as infrequently as 2 to 4 times annually could substantially lessen treatment burden compared with currently available biologics, something she said patients consistently value in clinical practice.

Disclosures: Vleugels has previously reported serving as a principal investigator and/or consultant for Pfizer, AstraZeneca, Apogee, Priovant, BMS, Lilly, and Johnson & Johnson.

Apogee Therapeutics Announces Positive 16-Week Part B Induction Dose Optimization Results from Phase 2 APEX Trial of Zumilokibart in Moderate-to-Severe Atopic Dermatitis. Apogee Therapeutics. May 27, 2026. 

Smith T. APEX: Positive 16-Week Data Released on Zumilokibart for Atopic Dermatitis. HCPLive. May 27, 2026. Accessed May 29, 2026. 

Videos

This interview highlights topline findings from Part B of the phase 2 APEX trial highlight the efficacy of zumilokibart (APG777) in adults with atopic dermatitis.

An expert in the treatment of atopic dermatitis shares her perspectives on patient communication and treatment optimization practices.

Patient Communication and Utilization of JAK Inhibitors in Atopic Dermatitis

Video content above is prompted by the following questions:

How do you educate and counsel patients who want to consider or are currently using a JAK inhibitor?

How do you discuss treatment targets and manage patient expectations?

What suggestions do you have for patients and healthcare professionals to optimize treatment of AD with JAK inhibitors?


An academic dermatologist discusses the safety profiles of abrocitinib and upadacitinib and provides clinical insights on patient monitoring practices.

Safety Data of Oral JAK Inhibitors in Atopic Dermatitis

Are there differences in safety data from clinical trials vs. real-world studies? What has been your clinical experience with abrocitinib and upadacitinib?

Discuss your monitoring schedule for patients taking JAK inhibitors.

How do you modify your monitoring protocol according to patient characteristics and preferences?
