A Randomized, Double-Blind, Placebo-Controlled Phase 2/3 Study of BLU-263 in Indolent Systemic Mastocytosis
This is a randomized, double-blind, placebo-controlled, Phase 2/3 study comparing the efficacy and safety of elenestinib (BLU-263) + symptom directed therapy (SDT) with placebo + SDT in participants with indolent systemic mastocytosis (ISM) whose symptoms are not adequately controlled by SDT. Parts 1 and 2 will enroll participants with ISM. Participants enrolled in Part 2 will roll over onto Part 3 to receive treatment with elenestinib in an open-label fashion following completion of the earlier Part. Part K will enroll participants with ISM who have previously received an approved selective KIT inhibitor. The study also includes pharmacokinetic (PK) groups that will enroll participants with ISM.
‣ 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