Designing Dermatology Trials for Durable Disease Control

Therapeutic innovation has reshaped the dermatology landscape, expanding treatment options for chronic inflammatory dermatoses such as psoriasis, atopic dermatitis, vitiligo, chronic hand eczema, and hidradenitis suppurativa. Yet for many late-stage development programs, the central challenge is no longer whether a therapy can produce a short-term response. It is whether that response lasts, whether the safety profile can support chronic use, and whether the evidence package reflects what patients, clinicians, regulators, and payers need to see. 

These conditions are lifelong and relapsing by nature. Patients may move through cycles of flare and remission, often with visible symptoms, itch, pain, functional limitations, and quality-of-life impacts that extend well beyond skin clearance. A therapy that performs well at 12 or 16 weeks may still fall short if patients relapse quickly after discontinuation, lose response over time, or experience safety concerns that limit long-term use. In late-stage development, durable disease control has become central to both regulatory strategy and real-world differentiation. 

Defining Success Beyond Initial Response 

That shift should influence endpoint strategy early. Traditional efficacy measures such as Psoriasis Area and Severity Index (PASI) and Eczema Area and Severity Index (EASI) remain critical, with thresholds such as PASI 75, PASI 90, and EASI response offering validated ways to assess improvement. But these measures capture only part of therapeutic value. Practice-oriented assessments such as Physician Global Assessment or Investigator Global Assessment can help contextualize disease improvement in ways that better reflect clinical decision-making. For psoriasis, PASI combined with PGA is often preferred; for atopic dermatitis, EASI and IGA are commonly used together. The strategic question is not simply which measure can support the primary endpoint, but which endpoint hierarchy can support the strongest possible labeling and differentiation claims. 

Designing for Durability 

Durability must also be designed into the trial, not treated as an exploratory afterthought. Withdrawal-randomized designs can be especially valuable in chronic relapsing disease. By re-randomizing responders to continued therapy or placebo and tracking time to relapse, development teams can assess whether a therapy provides sustained disease control or temporary symptom suppression. Evidence from psoriasis studies shows that time to relapse can vary substantially across biologic classes, with implications for treatment selection, payer evaluation, and patient preference.^1,2 Retreatment response is another important consideration, particularly for biologics and immunomodulatory therapies, where treatment interruptions may occur in real-world practice and immunogenicity can affect future response.³ 

Capturing the Patient Experience 

Patient experience is equally important. Chronic inflammatory dermatoses can affect sleep, mental health, social participation, work productivity, and daily functioning. Investigator-assessed severity measures alone may miss these dimensions. FDA’s patient-focused drug development work has reinforced the importance of well-defined, validated patient-reported outcome measures that are fit for the target condition and collected rigorously in pivotal trials.⁴ In dermatology, PRO-based claims related to itch reduction, symptom burden, or quality-of-life improvement can strengthen the relevance of a label when supported by validated tools and a clear statistical strategy. 

This is particularly important as disease-specific measures continue to mature. Chronic hand eczema provides a recent example, with Phase III delgocitinib studies using the IGA-Chronic Hand Eczema scale to evaluate treatment success in a way tailored to that condition.⁵ As more dermatology programs move toward precision medicine and indication-specific endpoints, early engagement on measurement strategy can help ensure trials capture outcomes that are both scientifically credible and meaningful to patients. 

Building a Long-Term Safety Story 

Long-term safety is another program-defining issue. These therapies may be used continuously for years, so the safety bar is fundamentally different from that of an acute-use treatment. Development teams need to anticipate the safety questions most likely to matter for the mechanism of action, route of administration, and target population. For systemic immunomodulators, that may include infection risk, malignancy, autoimmunity, and immunogenicity. Psoriasis, for example, has been associated with an elevated risk of cancer in some analyses, making long-term safety interpretation more complex.⁶ For topical therapies, reduced systemic exposure may be an advantage, but local tolerability, phototoxicity, skin atrophy, and systemic absorption under maximal-use conditions still require careful evaluation. 

Managing Execution Risk 

Operational execution can determine whether a strong design produces interpretable data. Dermatology endpoints require consistent visual assessment, and inter-rater variability can threaten signal detection across large, multicenter trials. Standardized investigator training, certification, calibration, and central review can help reduce scoring drift. Placebo response is another critical source of variability, particularly in atopic dermatitis, where placebo response rates can be substantial and influenced by concomitant therapy, baseline severity, and study duration.^7,8,9 Protocols should account for these drivers while preserving ethical care and patient feasibility. 

Feasibility matters because chronic disease trials can place meaningful demands on patients. Frequent visits, invasive assessments, or restrictive medication rules may increase dropout risk and reduce generalizability. Where scientifically appropriate, allowing standardized background care such as emollients or limited topical corticosteroids can reduce burden and better reflect real-world management. Similarly, thoughtful washout criteria are needed to balance scientific rigor with patient safety. Some prior therapies or concomitant medications may worsen disease or confound baseline assessment, while abrupt discontinuation of effective treatments can trigger rebound in certain conditions.^10,11

Planning for Approval and Differentiation 

The most competitive dermatology programs are built with the full product lifecycle in mind. Dose selection, comparator strategy, population definition, formulation, combination therapy, durability assessment, and long-term safety planning all shape what can be claimed at approval and how the product will be evaluated after launch. In crowded markets, a narrow efficacy story may not be enough. Programs that demonstrate sustained control, meaningful patient benefit, acceptable chronic-use safety, and real-world relevance are better positioned for regulatory success, payer confidence, and clinical adoption. 

As dermatology continues to evolve, late-stage trial design must evolve with it. The goal is not only to show that a therapy works at a single time point. It is to generate the evidence needed to show that it can help patients manage a lifelong disease with confidence, consistency, and meaningful improvement over time. 

Durable disease control starts with thoughtful trial design and experienced execution. Premier brings extensive dermatology clinical research expertise across major indications, helping sponsors build evidence strategies that support regulatory success, patient relevance, and long-term differentiation. Contact us to discuss your next dermatology development program. 

ABOUT PREMIER RESEARCH:  

Premier Research International LLC (Premier) is a global leader in clinical research and consulting services with expertise in driving an efficient and effective path to market for the life sciences industry. 

Premier is built with the needs of biotech in mind, turning breakthrough science into life-changing drugs, devices, and diagnostics by addressing trial complexity, overcoming development hurdles, and demonstrating product value. 

In response to rapid innovation in dermatology, Premier delivers clinical research expertise that goes beyond the surface. Our experts support dermatology programs across major indications, helping sponsors translate emerging science into successful clinical outcomes.   

Explore our dermatology clinical research experience.  

  

REFERENCES:  

1. Regnault MM. Time to Relapse After Discontinuing Systemic Treatment for Psoriasis: A Systematic Review. Am J Clin Dermatol. 2022;23(4):433-447. 
2. Huang Y. Predicting the Time to Relapse Following Withdrawal from Different Biologics in Patients with Psoriasis who Responded to Therapy: A 12-Year Multicenter Cohort Study. Am J Clin Dermatol. 2024;25(6):997-1008. 
3. Wang CY, et al. Biological Therapy Interruption and Re-Treatment in Chronic Plaque Psoriasis. J Drugs Dermatol. 2021;20(10):1063-1071. 
4. US Food and Drug Administration. CDER Patient-Focused Drug Development. March 21, 2025. Available at https://www.fda.gov/drugs/development-approval-process-drugs/cder-patient-focused-drug-development. 
5. Bissonnette R, et al. Efficacy and safety of delgocitinib cream in adults with moderate to severe chronic hand eczema (DELTA 1 and DELTA 2): results from multicentre, randomised, controlled, double-blind, phase 3 trials. Lancet. 2024;404(10451):461-473. 
6. Trafford AM, et al. Association of Psoriasis With the Risk of Developing or Dying of Cancer: A Systematic Review and Meta-analysis. JAMA Dermatol. 2019;155(12):1390-1403. 
7. Lee HH, et al. Placebo responses in randomized controlled trials for systemic therapy in atopic dermatitis: A systematic review and meta-analysis. J Am Acad Dermatol. 2020;82(1):62-71. 
8. Leshem YA, et al. Optimization of placebo use in clinical trials with systemic treatments for atopic dermatitis: an International Eczema Council survey-based position statement. J Eur Acad Dermatol Venereol. 2019;33(5):807-815. 
9. Serrano JC, et al. A Model-Based Meta-Analysis Framework Quantifying Drivers of Placebo Response in Atopic Dermatitis Trials. CPT Pharmacometrics Syst Pharmacol. 2026;15(2):e70150. 
10. Gupta AK, et al. Lithium therapy associated with hidradenitis suppurativa: case report and a review of the dermatologic side effects of lithium. J Am Acad Dermatol. 1995;32(2):382-386. 
11. Due E, et al. Discontinuation of methotrexate in psoriasis. Acta Derm Venereol. 2012;92(4):353-354.