The reason for changes to treatment strategy:

• Achieving inactive disease
• Achieving clinical remission
• Lack of effectiveness
• Occurrence of adverse events
• Patient's /Parent's decision
• Other

The adapted ACR Pediatric 30/50/70/90 criteria was used to determine efficacy defined as improvement from baseline of at least 30/50/70/90% respectively in at least 3 of the following 6 components

• Physician's Global Assessment of disease activity on a 0-100 mm VAS from 0 mm = no disease activity to 100 mm = very severe disease activity.
• Parent's or patient's Global Assessment of Subject's overall wellbeing on a 0-100 mm VAS from 0 mm= very well to 100 mm= very poor.
• Functional ability: Childhood Health Assessment Questionnaire (CHAQ©)
• Number of joints with active arthritis using the ACR definition (The ACR definition of active arthritis is any joint with swelling, or in the absence of swelling, limitation of motion accompanied by either pain on motion or tenderness not due to deformity)
• Number of joints with limitation of motion
• Laboratory measure of inflammation: CRP (mg/L)

Patients who achieved minimal disease activity and inactive disease can be defined based on JADAS-10 score. JADAS-10 is a composite disease activity score for JIA including four measures:

• physician's global assessment of disease activity (NRS)
• parent/guardian's or patient's global assessment of overall wellbeing (NRS)
• number of joints (up to 10) with active arthritis
• CRP/ESR, whichever is available

Inactive disease is achieved if either of the following two criteria is fulfilled:

• Wallace et al (2011) ACR criteria for inactive disease:
• no joints with active arthritis
• no active uveitis
• normal CRP/ESR, or if elevated, not attributable to JIA
• physician's global assessment of disease activity ≤ 1 (NRS)
• duration of morning stiffness attributable to JIA ≤ 15 minutes
• JADAS-10 score-based definition for inactive disease:
• physician's global assessment of disease activity (NRS)
• parent/guardian's or patient's global assessment of overall wellbeing (NRS)
• number of joints (up to 10) with active arthritis
• CRP/ESR, whichever is available

Patients with 6 consecutive months of inactive disease are defined as entering clinical remission.

Number of patients achieving complete resolution of dactylitis and enthesitis.

Change from baseline in pain score through numeric rating scale (NRS). Numeric rating scale spans from 0 (no pain) to 10 (strongest pain).

Summary of JIA ACR core components for all subjects and each JIA category.

Negative percent change indicates improvement.

JIA ACR criteria individual components:

• Number of joints with active arthritis
• Number of joints with limited range of motion
• C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR), whichever is available.
• Functional status using the Childhood Health Assessment Questionnaire (CHAQ) disability index and Health Assessment Questionnaire for adults.
• Physician global assessment of overall well-being through NRS.
• Parent/guardian's or patient's global assessment of overall well-being through NRS.

JADAS-10 stands for Juvenile Arthritis Disease Activity Score, with up to 10 joints assessed for active arthritis as part of the score. JADAS-10 individual criteria are:

• Physician's global assessment: NRS scale - 0 (inactive disease ) to 10 (active disease)
• Parent/guardian's or patient's global assessment: NRS scale - 0 (inactive disease ) to 10 (active disease)
• Number of joints with active arthritis: from 0 active joints to 10 active joints.
• CRP/ESR, whichever is available: Westergren erythrocyte sedimentation rate (ESR), normalized to a 0-10 scale. The CRP was truncated to a 0-10 scale accord¬ing to the following formula: (CRP (mg/l)-10)/10, similar to the normalized ESR used in the original JADAS.

Before calculation, CRP values <10 mg/l were converted to 10 and CRP values >110 mg/l were converted to 110.

JADAS-10 stands for Juvenile Arthritis Disease Activity Score, with up to 10 joints assessed for active arthritis as part of the score. The score spans from 0 to 40. Lower values mean lower activity and higher values mean higher activity.

Change from baseline in swollen joint count

Change from baseline in tender joint count

Total dactylitis count

Total enthesitis count, number of affected sites.

The Enthesitis score using Maastricht Ankylosing Spondylitis Enthesitis Score (MASES) asks for evaluation of swelling and tenderness at different anatomical locations.

All locations are scored as 0 "no activity" or 1 "activity". The MASES is the sum of all site scores.

JIA-related manifestations:

• Uveitis presence.
• Serositis presence.
• General lymphadenopathy presence.
• Fever presence.

Modified Schober's test is measuring lumbar spine mobility quantitatively. It measures lumbar spine flexion range of motion.

To conduct the test, the patient stands upright. The examiner locates the two posterior superior iliac spines and draws a horizontal line between them. A second point is marked 15cm above this line.Then the patient is asked to bend forwards as far as possible whilst keeping the knees fully extended. The distance between the previously marked points is measured again and indicates the amount of flexion.

For patients with Enthesitis-Related Arthritis (ERA), the overall and nocturnal back pain through NRS will be recorded. NRS stands for Numerical Rating Scale: 0 (no pain) to 10 (strongest pain).

The IGA Mod is a simple score for the evaluation of psoriasis:

0 = clear (e.g., no signs of psoriasis, some post-inflammatory hyperpigmentation may be present);

1. = almost clear (e.g., no thickening, normal or pink coloration);
2. = mild (e.g., mild thickening, pink to light red coloration),
3. = moderate (e.g., moderate thickening, dull to bright red);
4. = severe (e.g., severe thickening, bright to deep red).

For patients with Juvenile Psoriatic Arthritis (JPsA), the PASI score will be calculated. The PASI is used for assessing and grading the severity of psoriatic lesions and their response to therapy. PASI scores can range from a lower value of 0, corresponding to no signs of psoriasis, up to a theoretic maximum of 72.0.

Number of patients with relevant Juvenile Idiopathic Arthritis (JIA)-related manifestations (such as uveitis, serositis)

Time from symptom onset to diagnosis of Enthesitis-Related Arthritis (ERA) or Juvenile Psoriatic Arthritis (JPsA)

Disease duration at the time of secukinumab initiation

Therapy duration prior to start of secukinumab (including all drug and non-drug therapies prescribed for ERA or JPsA)

Number of treatment lines prior to start of secukinumab

Prior medication and dosage (including all drug and non-drug therapies prescribed for ERA or JPsA)