A Study to Investigate the Safety and Efficacy of Emapalumab, an Anti-IFN-gamma mAb in Patients With Systemic Juvenile Idiopathic Arthritis (sJIA) or Adult-onset Still's Disease (AOSD) Developing Macrophage Activation Syndrome/Secondary HLH (MAS/sHLH)

Swedish Orphan Biovitrum14 enrolled

Overview

Macrophage Activation Syndrome (MAS) is a rare, life-threatening condition characterized by uncontrolled hyperinflammation which may develop on the background of systemic Juvenile Idiopathic Arthritis (sJIA) or Adult-onset Still's Disease (AOSD). Emapalumab is a monoclonal antibody neutralizing interferon-gamma (IFN-gamma), a key cytokine which contributes to the inflammation and tissue damage seen in MAS. The purpose of this study is to assess the safety, tolerability and efficacy of emapalumab in sJIA or AOSD participants developing MAS, presenting an inadequate response to high dose glucocorticoid treatment.

Study Type

INTERVENTIONAL

Allocation

Purpose

TREATMENT

Masking

NONE

Enrollment

Conditions

Macrophage Activation Syndrome Lymphohistiocytosis, Hemophagocytic Arthritis, Juvenile Adult Onset Still Disease

Eligibility

Sex: ALLMin age: 0 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Patients of both genders * For sJIA patients: Confirmed sJIA diagnosis. For patients presenting with MAS in the context of the onset of sJIA, high presumption of sJIA will suffice for eligibility. For AOSD patients: confirmed AOSD diagnosis as per Yamaguchi criteria. * Diagnosis of active MAS. * An inadequate response to high dose i.v. glucocorticoid treatment administered for at least 3 days as per local standard of care (including but not limited to pulses of 30 mg/kg PDN on 3 consecutive days). High dose i.v. glucocorticoid should not be lower than 2 mg/kg/day of PDN equivalent in 2 divided doses (or at least 60 mg/day in patients of 30 kg or more). In case of rapid worsening of the patient's condition and/or lab parameters, inclusion may occur within less than 3 days from starting high dose i.v. glucocorticoids. * Tocilizumab, TNF inhibitors and canakinumab, if administered, have to be discontinued before emapalumab initiation. * Having received guidance on contraception for both male and female patients sexually active and having reached puberty. Females of child-bearing potential require use of highly effective contraceptive measures. Males with partners(s) of child-bearing potential must agree to take appropriate precautions. * Informed consent provided by the patient (as required by local law), or by the patient's legally authorized representative(s) with the assent of patients who are legally capable of providing it, as applicable. Exclusion Criteria: * Diagnosis of suspected or confirmed primary HLH or HLH consequent to a neoplastic disease. * Active mycobacteria (typical and atypical), Histoplasma Capsulatum, Shigella, Salmonella, Campylobacter and Leishmania infections. * Clinical suspicion of latent tuberculosis. * Positive serology for HIV antibodies. * Presence of malignancy. * Patients who have another concomitant disease or malformation severely affecting the cardiovascular, pulmonary, CNS, liver or renal function that in the opinion of the Investigator may significantly affect likelihood to respond to treatment and/or assessment of emapalumab safety. * History of hypersensitivity or allergy to any component of the study drug * Receipt of a BCG vaccine within 12 weeks prior to screening. * Receipt of live or attenuated live vaccines (other than BCG) within 6 weeks prior to screening. * Pregnant or lactating female patients.

Outcomes

Primary Outcomes

Incidence, Severity, Causality, and Outcomes of AEs (Serious and Nonserious)

Time frame: Up to Week 8

Evolution of Laboratory Parameters

Shifts from baseline in the following MAS-relevant laboratory parameters are reported: * Leukocytes * Platelets * Lactate dehydrogenase (LDH) * Alanine aminotransferase (ALT) * Aspartate aminotransferase (AST) * Ferritin * C-reactive protein * Activated partial thromboplastin time (aPTT) * Prothrombin time * D-dimer * Fibrinogen

Time frame: Up to Week 8

Number of Participants Withdrawn Due to Safety Reasons

Time frame: Up to Week 8

Number of Participants Achieving MAS Remission at Week 8 After Initiation of Emapalumab Treatment

Remission from MAS was evaluated according to the following criteria: Resolution of clinical signs and symptoms according to the investigator (MAS clinical signs and symptoms activity score ≤ 1) and Normalization of laboratory parameters relevant to MAS, as follows: * WBC count and platelet count above the LLN. * LDH below 1.5 × the ULN. * ALT and AST both below 1.5 × the ULN. * Fibrinogen higher than 100 mg/dL. * Ferritin levels decreased by at least 80 % from values at screening or baseline (whichever was higher) or below 2000 ng/mL, whichever was lower.

Time frame: Week 8

Time to First MAS Remission

Time frame: Up to Week 8

Number of Participants for Whom Glucocorticoids Could be Permanently Tapered at Any Time During the Study

Permanently tapering by at least 50% of the equivalent dose of prednisone. This was defined as achieving reduction of 50% of the baseline dose \[SD0\] and maintaining the reduction until the end of study).

Time frame: Up to Week 8

Time to Achievement of Permanent Glucocorticoids Tapering

Time to achievement of permanent glucocorticoid tapering by at least 50% of the equivalent dose of prednisone administered at emapalumab treatment start.

Time frame: Up to Week 8

Survival Time

Number of participants alive at the end of the study

Time frame: Up to Week 8

Number of Participants Withdrawn From the Study Due to Lack of Efficacy

Number of participants withdrawn from the study due to lack of efficacy

Time frame: Up to Week 8

Levels of Emapalumab Concentration

On all infusion days, PK samples were collected before the infusion start and between 15 and 30 minutes after infusion completion. In addition, following the first emapalumab infusion, PK samples were collected approximately 24 and 48 hours post-infusion, and following the second emapalumab infusion, PK samples were collected approximately 48 hours post-infusion. Upon treatment completion, PK samples were collected on all non-infusion visits until the 4-week follow-up visit/EOS.

Time frame: Data from the following time points are presented: SD0 (pre- and post-dose), Week 4 Visit 2 (pre- and post-dose), and 4-week follow-up visit/EoS.

Pharmacodynamic Parameters

Levels of total INF-gamma, CXCL9 and CXCL10

Time frame: Up to Week 8

Number of Participants Who Demonstrated a Presence of Circulating Antibodies Against Emapalumab to Determine Immunogenicity

The presence of circulating antibodies against emapalumab was inferred by positive results for anti-drug antibodies (ADAs).

Time frame: Up to Week 8

A Study to Investigate the Safety and Efficacy of Emapalumab, an Anti-IFN-gamma mAb in Patients With Systemic Juvenile Idiopathic Arthritis (sJIA) or Adult-onset Still's Disease (AOSD) Developing Macrophage Activation Syndrome/Secondary HLH (MAS/sHLH)

Overview

Conditions

Interventions

Eligibility

Locations (5)

Outcomes

Primary Outcomes