Trial Outcomes & Findings for Evaluate Efficacy, Safety and Tolerability, PK and PD of Emapalumab in Children and Adults With MAS in Still's or SLE (NCT NCT05001737)

Evaluate Efficacy, Safety and Tolerability, PK and PD of Emapalumab in Children and Adults With MAS in Still's or SLE

Resolution of clinical signs and symptoms present at baseline: The macrophage activation syndrome (MAS) clinical activity will be measured on a visual analog scale (VAS) 10 cm. Resolution of clinical signs and symptoms present at baseline: The MAS clinical activity will be measured on a visual analog scale (VAS) 10 cm. Clinical signs will be considered as resolved if VAS is below or equal to 1/10. And Normalization of laboratory parameters relevant to MAS, as follows: WBC above LLN, platelet count above LLN, LDH below 1.5 ULN, ALT below 1.5 ULN, AST below 1.5 ULN, fibrinogen higher than 100 mg/dL, ferritin levels decreased by at least 80 % from values at screening or baseline (whichever is higher) or below 2000 ng/ml, whichever is lower

GC tapering as per investigator discretion

GC tapering as per investigator discretion

Median time to achieve GCs tapering to a dose \< 50 % of PDN equivalent at the time of emapalumab start or to the same (or lower) dose being administered before the occurrence of MAS (in patients already treated for the underlying condition), or to ≤1mg/kg/Day of PDN Equivalent, whichever occurs first at any time during the study GC tapering as per investigator discretion

Time to CR until EOS Resolution of clinical signs and symptoms present at baseline: The MAS clinical activity was measured on a visual analog scale (VAS) 10 cm. Definition of CR: Resolution of clinical signs and symptoms present at baseline: MAS clinical activity was measured on a 10-cm VAS. Clinical signs were considered resolved if VAS was below or equal to 1/10. and Normalization of laboratory parameters relevant to MAS as follows: * WBC \>LLN. * Platelet count \>LLN. * LDH \<1.5 ULN. * ALT \<1.5 ULN. * AST \<1.5 ULN. * Fibrinogen \>100 mg/dL. * Ferritin levels decreased by at least 80% from values at Screening or baseline (whichever was higher) or \<2000 ng/mL, whichever was lower.

Resolution of clinical signs and symptoms present at baseline: The MAS clinical activity was measured on a visual analog scale (VAS) 10 cm. CR: Resolution of clinical signs and symptoms present at baseline: MAS clinical activity was measured on a 10-cm VAS. Clinical signs were considered resolved if VAS was below or equal to 1/10. and Normalization of laboratory parameters relevant to MAS as follows: * WBC \>LLN. * Platelet count \>LLN. * LDH \<1.5 ULN. * ALT \<1.5 ULN. * AST \<1.5 ULN. * Fibrinogen \>100 mg/dL. * Ferritin levels decreased by at least 80% from values at Screening or baseline (whichever was higher) or \<2000 ng/mL, whichever was lower. PR: Resolution or improvement in clinical signs and symptoms measured by the MAS clinical activity on the VAS. The patient was classified as PR if he or she presented a VAS \<4/10. and Normalization of at least 3 of the abnormal baseline laboratory parameters relevant to MAS, as defined above.

Time to first overall response CR: Resolution of clinical signs and symptoms present at baseline: MAS clinical activity was measured on a 10-cm VAS. Clinical signs were considered resolved if VAS was below or equal to 1/10. and Normalization of laboratory parameters relevant to MAS as follows: * WBC \>LLN. * Platelet count \>LLN. * LDH \<1.5 ULN. * ALT \<1.5 ULN. * AST \<1.5 ULN. * Fibrinogen \>100 mg/dL. * Ferritin levels decreased by at least 80% from values at Screening or baseline (whichever was higher) or \<2000 ng/mL, whichever was lower. PR: Resolution or improvement in clinical signs and symptoms measured by the MAS clinical activity on the VAS. The patient was classified as PR if he or she presented a VAS \<4/10. and Normalization of at least 3 of the abnormal baseline laboratory parameters relevant to MAS, as defined above.

Number of patients with MAS recurrence at anytime after achievement of CR

Number of patients withdrawn from the study due to lack of response as per Investigator decision

Number of patients alive at the end of study

number of patients that experienced at least one AE (serious and non-serious).

Number of participants withdrawn from study treatment due to adverse event

Number of patients with clinically meaningful changes in hematology and chemistry laboratory parameters from baseline

Pediatric Quality of Life Inventory (PedsQL™; Generic Core Scales and Infant Scales, Acute versions) The PedsQL is scored on a 5-point Likert scale from: 0 (Never) to 4 (Almost always) Then, for ease of interpretability, items are reversed scored and linearly transformed to a 0-100 scale, so that higher scores indicate better HRQOL (Health-Related Quality of Life). To reverse score, transform the 0-4 scale items to 0-100 as follows: 0=100, 1=75, 2=50, 3=25, 4=0 To create the Total Scale Score, the mean is computed as the sum of all the items over the number of items answered on all the Scales (this also accounts for missing data). If more than 50% of the items in the scale are missing, the Scale Scores should not be computed. If 50% or more items are completed: Impute the mean of the completed items in a scale

Health-related quality of life: Global Assessment: Clinician Global Impression of Severity Number of patients having an overall severity of the health status over the past week assessed by the clinician as None, Mild, Moderate, or Severe, at the specified timepoints.

Health-related quality of life: Global Assessment: Patient/Parent Global Impression of Severity Number of patients having an overall severity of the health status over the past week assessed by the Patient/Parent as None, Mild, Moderate, or Severe, at the specified timepoints.

Serum concentrations of emapalumab vs. time

Levels of the main IFN-γ-induced chemokine (CXCL9).

Levels of MAS markers; sCD25 (Soluble CD25 (i.e., soluble IL-2 receptor))

Occurrence of ADAs to emapalumab until EOS (1 year after last dose of emapalumab) Baseline and overall incidence