Systemic Mastocytosis Clinical Trials

‣ All Participants:

• Participant must have an Eastern Cooperative Oncology Group Performance Status (ECOG PS) of 0 to 2.

‣ Part 1 and PK groups:

⁃ Participant has confirmed diagnosis of ISM, confirmed by Central Pathology Review

⁃ Participant must have failed to achieve adequate symptom control for 1 or more Baseline symptoms, as determined by the Investigator, with at least 2 of the following symptom-directed therapies administered: H1 blockers, H2 blockers, proton-pump inhibitors, leukotriene inhibitors, cromolyn sodium, corticosteroids, or omalizumab.

⁃ Participants must have SDT for ISM symptom management stabilized for at least 14 days prior to starting screening procedures.

⁃ For participants receiving corticosteroids, the dose must be ≤ 20 mg/day prednisone or equivalent, and the dose must be stable for ≥ 14 days.

‣ Part K:

• Participant has confirmed diagnosis of ISM, confirmed by Central Pathology Review

‣ Part S:

• Participant has confirmed diagnosis of SSM, confirmed by Central Pathology Review of BM biopsy and central review of B- and C-findings by WHO diagnostic criteria.

‣ Part 2:

• Participant has confirmed diagnosis of ISM, confirmed by Central Pathology Review