This clinical trial focuses on a condition known as Systemic Mastocytosis, which is a rare disorder where there is an abnormal accumulation of mast cells in various parts of the body. The study involves a medication called Avapritinib, also known by its code name BLU-285. Avapritinib is provided in the form of a film-coated tablet and is taken orally.
The purpose of this study is to allow patients who have previously participated in an Avapritinib clinical study to continue receiving the medication until it becomes commercially available. This is intended for patients who have been benefiting from the treatment, as determined by their doctor. The study is open-label, meaning both the researchers and participants know what treatment is being administered.
Participants in this study will continue to take Avapritinib as they did in their previous study. The study will last until the medication is commercially available, or until the participant no longer benefits from the treatment. This trial is designed to ensure that patients who have shown positive results with Avapritinib can maintain their treatment without interruption.



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