Evaluation of Enpatoran Efficacy and Safety in Systemic and Cutaneous Lupus Erythematosus: A Phase 2 Randomized, Double-Blind, Placebo-Controlled Study

The primary objective of this study is to evaluate the **dose-response** relationship of enpatoran in reducing disease activity in patients with systemic lupus erythematosus (SLE) and cutaneous lupus erythematosus (CLE), specifically using the CLASI-A (Cutaneous Lupus Erythematosus Disease Area and Severity Index Activity) as a measure. This is clinically relevant as it aims to determine the optimal dosing of enpatoran to effectively manage and reduce the symptoms associated with these chronic autoimmune conditions, potentially improving patient outcomes and quality of life.

Secondary objectives include evaluating the dose-response relationship of enpatoran in reducing disease activity based on the BICLA (BILAG-based Composite Lupus Assessment) response rate. This secondary measure provides additional insights into the efficacy of enpatoran across different clinical assessment tools, further supporting its potential therapeutic role in managing lupus-related disease activity.

The clinical trial involves a total of **405 participants** diagnosed with **systemic lupus erythematosus (SLE)** and **cutaneous lupus erythematosus (CLE)**. The study population includes both male and female subjects, with an age range corresponding to categories 3 and 4, which typically encompass adults. Participants were selected based on specific inclusion criteria, such as having active CLE or SLE with a defined disease activity index. The trial population includes individuals receiving stable doses of standard care therapies for lupus, such as immunomodulators, immunosuppressants, oral corticosteroids, and/or topical corticosteroids. The study also considers vulnerable populations, ensuring a comprehensive evaluation of the treatment's efficacy across diverse demographic groups. Lifestyle factors such as diet and physical activity were not specified in the available data.

The clinical trial is designed as a **randomized, double-blind, placebo-controlled** study to evaluate the efficacy and safety of **Enpatoran** in participants with **systemic lupus erythematosus (SLE)** and **cutaneous lupus erythematosus (CLE)**. The trial employs a dose-ranging, parallel, and adaptive approach to assess the dose-response relationship of Enpatoran in reducing disease activity, specifically measured by the Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI-A). The study is expected to span approximately 24 months, with an estimated recruitment start date of June 15, 2022, and an anticipated end date of December 31, 2024.

Participants will undergo a series of study visits, beginning with an inclusion (screening) visit to confirm eligibility based on criteria such as active CLE with a CLASI-A score of 8 or higher, and active SLE with specific BILAG and SELENA-SLEDAI scores. Following the screening, participants will be randomized to receive either Enpatoran or a placebo, administered orally in the form of film-coated tablets. The trial includes multiple follow-up visits to monitor the primary and secondary endpoints, which include changes in disease activity indices and safety profiles, assessed by the incidence of treatment-emergent adverse events and other clinical parameters.

The primary endpoints are evaluated at Week 16 for Cohort A and Week 24 for Cohort B, with secondary endpoints assessed at various intervals throughout the study. The end-of-study visit will conclude the participant's involvement, which is expected to last up to 24 weeks, depending on the cohort assignment. Conditions that may lead to early termination from the study include the occurrence of serious adverse events or significant deviations from the protocol-defined criteria. The trial is not categorized as low intervention and is conducted under the sponsorship of Merck Healthcare KGaA, with Enpatoran being the investigational product under evaluation.

The clinical trial involves the administration of **Enpatoran**, an investigational medication, to evaluate its efficacy and safety in participants with **Systemic Lupus Erythematosus** and **Cutaneous Lupus Erythematosus**. Enpatoran is provided in the form of a film-coated tablet, intended for **oral use**. The active substance in Enpatoran is a chemical compound, and the product is manufactured by Merck Healthcare KGaA. The dosing schedule for Enpatoran is designed to be flexible, with a maximum treatment period of 24 weeks. The specific dosage and frequency of administration are determined based on the study protocol, with the aim of assessing the dose-response relationship in reducing disease activity as measured by the CLASI-A score. Participant compliance with the dosing regimen is monitored throughout the study to ensure adherence to the protocol.

In addition to the experimental treatment, the study includes the use of a **placebo** control, referred to as Enpatoran placebo. The placebo is also administered in the form of a film-coated tablet for oral use, matching the appearance of the active medication to maintain the double-blind nature of the trial. The placebo serves as a comparator to evaluate the efficacy of Enpatoran against a non-active treatment. Participants receiving the placebo will follow the same dosing schedule and treatment period as those receiving the active medication. Compliance with the placebo regimen is similarly monitored to ensure the integrity of the study results.

All participants in the trial will continue to receive standard-of-care therapy for their condition, as determined by their healthcare providers. This non-experimental treatment is administered alongside the investigational medication or placebo, allowing for the assessment of Enpatoran's efficacy and safety in conjunction with existing therapeutic regimens. The study protocol outlines the specific criteria for standard-of-care therapy to ensure consistency across study sites and participants.

The efficacy of **Enpatoran** in the treatment of Systemic Lupus Erythematosus (SLE) and Cutaneous Lupus Erythematosus (CLE) will be assessed through a series of primary and secondary endpoints. The primary endpoints include the percent change from baseline in the Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI-A) at Week 16 for Cohort A, and the British Isles Lupus Assessment Group (BILAG)-Based Composite Lupus Assessment (BICLA) Response at Week 24 for Cohort B. Secondary endpoints will evaluate various parameters such as the safety profile, changes in the Cutaneous Lupus Activity Investigator's Global Assessment (CLA-IGA), and Physician's Global Assessment of Cutaneous Lupus Disease Activity at specified time points (Week 16 and Week 24).

Additional secondary endpoints for Cohort B include the Systemic Lupus Erythematosus Responder Index-4 (SRI-4) Response, Lupus Low Disease Activity State (LLDAS) Attainment, and Remission Attainment at Week 24. The trial will also measure changes from baseline in the Skindex 29+3 Symptom Domain Score, Functioning and Emotion Domain Scores, and the Functional Assessment of Chronic Illness Therapy (FACIT)-Fatigue Scores at Week 24. The efficacy assessments will be conducted using validated scales and clinical evaluations at predetermined intervals to ensure comprehensive data collection and analysis.