Study to Evaluate the Efficacy, Safety and Tolerability of MAS825 in Patients With Monogenic IL-18 Driven Autoinflammatory Diseases, Including NLRC4-GOF, XIAP Deficiency, or CDC42 Mutations

Inclusion Criteria:

For all Patients:

1. Male and female patients weighing at least 3 kg

2. Written informed consent by parent(s)/legal guardian(s) for the pediatric patients
and assent by the pediatric patient (depending on local requirements) must be
obtained before any study-specific assessment is performed. For adult patients,
written informed consent by patients capable of giving consent, or when the patient
is not capable of giving consent, by his/her legal/authorized representative (if
allowed according to local requirements).

Cohort 1 specific inclusion criteria:

3. Patients with a genetic diagnosis of either NLRC4-GOF, XIAP deficiency, or CDC42
mutation

4. Clinical history and investigations consistent with autoinflammation and infantile
enterocolitis (AIFEC/NLRC4-GOF), XIAP or CDC42. XIAP patients must have persistent
disease or be resistant to escalating therapy.

5. At first treatment, evidence of active disease as assessed by inflammatory markers
and PGA

Cohort 2 specific inclusion criteria:

6. Patients with a genetic diagnosis of NLRC4-GOF, XIAP deficiency, or CDC42 mutations
who are being treated with MAS825 in a Novartis Managed Access Program (MAP).

Exclusion Criteria:

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

2. Signs and symptoms, in the judgment of the investigator, of clinically significant
active bacterial, fungal, parasitic or viral infections, excluding chronic
Epstein-Barr Virus (EBV).

- COVID-19 specific: If in line with health and governmental authority guidance,
it is highly recommended that testing to exclude COVID-19 using PCR or
comparable approved methodology be completed within 1 week prior to first
dosing.

3. Any conditions or significant medical problems, which in the opinion of the
investigator places the patient at unacceptable risk for MAS825 therapy

4. Previous treatment with anti-rejection and/or immunomodulatory drugs within the past
28 days or 5 half-lives (whichever is the longer) for immunomodulatory therapeutic
antibodies (or as listed in the prohibited medications section) prior to MAS825
treatment with the exceptions of glucocorticoids, cyclosporin and targeted binding
or blocking therapies.

5. A positive HIV test result at Screening. Evidence of prior testing within 3 months
is sufficient.

6. A positive Hepatitis B surface antigen (HBsAg) or Hepatitis C test result at
Screening. Evidence of prior testing within 3 months is sufficient.

7. Presence of tuberculosis infection as defined by a positive TB test at Screening.
Evidence of prior testing within 3 months is sufficient.

8. Live vaccinations within 1 month prior to MAS825 treatment, during the trial, and up
to 3 months following the last dose.

9. Pregnant or nursing (lactating) females.

10. Female patients of child-bearing potential (or Tanner stage 2 or above) who are or
might become sexually active, agree to use highly effective contraceptive methods to
prevent pregnancy while on MAS825 therapy

11. Patients weighing >160 kg at Screening.

12. For CDC42 mutation patients: Takenouchi-Kosaki syndrome - CDC42 mutations associated
with a diverse syndrome characterized by variable development delays, cardiac, brain
and hematological abnormalities.