The study is a phase II trial designed to evaluate the clinical efficacy, safety, and tolerability of MAS825 (arumakimig) in pediatric and adult participants with Still's disease

This is a multicenter, open-label, single-arm study to assess clinical efficacy, safety and tolerability of MAS825 in participants (both pediatric and adult) with Still's disease who have had inadequate response to IL-1 and/or IL-6 or other available therapies. Participants with associated lung disease and/or macrophage activation syndrome may also be included.

This study has three periods (Screening, Treatment Period 1, and Treatment Period 2) and a total duration of approximately 16 months.

Inclusion Criteria:

• Age ≥ 1 with a diagnosis of Still's Disease

• Active diseases defined as:

• CRP or ferritin levels greater than ULN, and any of:

  • Fever ≥ 38°C attributed to Still's Disease activity and documented for a number of days prior to Day 1 or
  • Rash attributed to Still's Disease activity or
  • Musculoskeletal involvement: arthritis in a number of joints per ACP criteria for active joint or
  • Serositis or
  • Macrophage activation syndrome activity as defined by ferritin levels and at least one of: platelet count, a biomarker or fibrinogen levels attributed to Still's Disease activity by the investigator

• Intolerance or inadequate response to available biologic therapy

Exclusion Criteria:

• Patients out of weight range

• Ongoing or previous treatment with immunomodulatory drugs

  • A limited number of Still's Disease patients that have previously received MAS825 through a managed access program are permitted on the study

• Glucocorticoid dose exceeding a set limit

• Any conditions or significant medical problems which places the patient at unacceptable risk for MAS825 therapy

  • Still's disease patients with evidence of macrophage activation syndrome are permitted in the study
  • Still's Disease patients with evidence of interstitial lung disease including those requiring supplemental oxygen therapy are permitted in the study

• History of ongoing, chronic or possibly recurrent infection (e.g. HIV, TB, HCV, HBV) and/or symptoms and signs of clinically significant active bacterial, fungal or viral infections

• Live vaccinations within a set time prior to MAS825 treatment. Live vaccines are prohibited up to several months following the last dose

• History of malignancy of any organ system, including post-transplant lymphoproliferative disorder, treated or untreated, within a number of years, regardless of whether there is evidence of local recurrence and metastases

• History of hypersensitivity to any of the study drugs or to drugs of similar chemical classes or to any of the excipients

• Pregnant or breastfeeding women

• Women of child-bearing potential who do not agree to comply with required contraceptive use

Other protocol-defined inclusion/exclusion criteria may apply.

Novartis is committed to sharing with qualified external researchers, access to patient-level data and supporting clinical documents from eligible studies. These requests are reviewed and approved by an independent review panel on the basis of scientific merit. All data provided is anonymized to respect the privacy of patients who have participated in the trial in line with applicable laws and regulations. This trial data availability is according to the criteria and process described on www.clinicalstudydatarequest.com.