Long-Term Safety and Efficacy of Subcutaneous Belimumab in Adults with Systemic Sclerosis-Associated Interstitial Lung Disease: An Open-Label Study

The primary objective of this study is to describe the long-term **safety** and tolerability of **belimumab** treatment in participants with systemic sclerosis associated interstitial lung disease (SSc-ILD). This is clinically relevant as it aims to ensure that the therapeutic use of belimumab does not result in adverse effects over extended periods, which is crucial for patient safety and treatment adherence in managing SSc-ILD.

Secondary objectives include describing the long-term effect of belimumab on lung function in participants with SSc-ILD. This is important for understanding the potential benefits of belimumab in preserving or improving pulmonary function, which is a critical aspect of managing interstitial lung disease associated with systemic sclerosis.

The clinical trial involves a total of **136 participants** diagnosed with **bronchial diseases**. The study population includes both male and female subjects, with an age range that spans from young adults to older adults. Participants were selected based on their completion of a prior study (Study 218224) and their ability to continue without treatment failure, such as the initiation of new immunosuppressive medications or discontinuation of study medication. The trial does not focus on a vulnerable population. Participants are required to have an area of skin suitable for subcutaneous injection and must be capable of self-administering the study medication or have assistance from a caregiver or healthcare professional. Female participants must not be pregnant or breastfeeding and must adhere to effective contraceptive measures if of child-bearing potential. The trial does not impose specific lifestyle considerations such as diet or physical activity. The selection criteria ensure that participants are capable of providing informed consent and complying with study requirements.

The clinical trial is designed to evaluate the long-term safety and efficacy of **belimumab** administered subcutaneously in adults with systemic sclerosis-associated interstitial lung disease (SSc-ILD). This is an open-label, phase 3 study, which aims to provide comprehensive data on the safety and tolerability of the treatment. The trial is expected to commence recruitment on April 20, 2025, and is projected to conclude by December 31, 2029. Participants will be involved in the study for a maximum treatment period of 260 weeks, during which they will receive a maximum daily dose of 200 mg of belimumab, with a total dose not exceeding 52,000 mg.

The trial will include several key visits, starting with an inclusion (screening) visit to confirm eligibility based on specific criteria, such as completion of a prior study and the absence of treatment failure. Participants must have an area suitable for subcutaneous injection and be capable of self-administering the medication or have assistance. Female participants must adhere to strict contraceptive measures if of childbearing potential. The primary endpoint of the study is the incidence of adverse events (AEs), adverse events of special interest (AESIs), and serious adverse events (SAEs). Secondary endpoints include the absolute change from baseline in forced vital capacity (FVC) at specified intervals.

Study visits will be scheduled at regular intervals, including follow-up visits at weeks 12, 26, and 52, and every 52 weeks thereafter, to monitor the participants' health and response to the treatment. The end-of-study visit will mark the conclusion of the participant's involvement, where final assessments will be conducted. Participants may be terminated early from the study if they initiate new immunosuppressive or immunomodulatory medication for SSc-related disease activity or if they discontinue the study medication for any reason. The trial is not categorized as low intervention, ensuring rigorous monitoring and data collection throughout the study duration.

The clinical trial involves the administration of **Benlysta**, a **200 mg solution for injection** in a pre-filled pen, developed by GlaxoSmithKline (Ireland) Limited. The active substance in Benlysta is **belimumab**, classified under the ATC code L04AA26. This pharmaceutical form is a solution for injection, specifically designed for **subcutaneous use**. The medication is delivered using a customized version of the Scandinavian Health Limited (SHL) MollyTM platform, which is a prefilled syringe assembled with additional functional components to create a prefilled pen. The maximum daily dose of Benlysta is 200 mg, with a total maximum dose of 52,000 mg over the course of the study. The treatment period is set for a maximum of 260 days. The administration schedule is determined by the study protocol, ensuring consistent dosing and monitoring of participant compliance.

In this study, no non-experimental treatments such as standard-of-care therapy, placebo, or comparator treatments are utilized. The focus is solely on evaluating the long-term safety and efficacy of belimumab in participants with systemic sclerosis-associated interstitial lung disease (SSc-ILD). Compliance with the dosing schedule is monitored throughout the trial to ensure adherence to the treatment regimen. The study is designed to provide comprehensive data on the safety and tolerability of belimumab when administered subcutaneously in the specified patient population.

The clinical trial aims to assess the efficacy of **belimumab** in adults with systemic sclerosis-associated interstitial lung disease (SSc-ILD). Efficacy will be evaluated using secondary endpoints, specifically the absolute change from baseline in forced vital capacity (FVC) measured in milliliters. These measurements will be taken at various timepoints, including Weeks 12, 26, and 52, and subsequently every 52 weeks thereafter. The collection and analysis of these efficacy parameters will be conducted using standardized laboratory tests to ensure accuracy and reliability. The trial is designed to provide comprehensive data on the long-term effects of belimumab treatment in this patient population.