Avapritinib is for the treatment of adults with unresectable or metastatic gastrointestinal stromal tumor (GIST) harboring a PDGFRA exon 18 mutation.
GIST harboring a PDGFRA exon 18 mutation do not respond to standard therapies for GIST.
Response rate with almost 85% of patients experiencing tumor shrinkage with this targeted drug.
300 mg or 400 mg once daily was provided until disease progression or unacceptable toxicity occurred.
Patients harboring a PDGFRA exon 18 mutation had an overall response rate of 84%, including 7% having complete responses and 77% having partial responses.
Among patients with PDGFRA D842V mutations, the ORR was 89%, with 8% and 82% having complete and partial responses, respectively.
61% of patients had responses that lasted ≥6 months.
The most common side effects reported with avapritinib were edema, nausea, fatigue/asthenia, cognitive impairment, vomiting, decreased appetite, diarrhea, hair color changes, increased lacrimation, abdominal pain, constipation, rash and dizziness.
Avapritinib is approved to treat advanced systemic mastocytosis, according to phase 1 and phase 2 clinical trial data.
Single-agent avapritinib was approved by the FDA for the treatment of adult patients with advanced systemic mastocytosis, including aggressive systemic mastocytosis (ASM), systemic mastocytosis with associated hematological neoplasm (SM-AHN), and mast cell leukemia (MCL).
Ayvakit is the tradename.
Phase 1 EXPLORER and the phase 2 PATHFINDER trials showed remarkable clinical efficacy to patients with advanced systemic mastocytosis.
Then daily dose of 200 mg, the overall response rate was 57% which included a complete remission rate of 28% and partial remission rate of 28%.
The median response duration was 38.3 months , and there was also a 2.1-month median time to response.
Adverse effects associated with avapritinib include: edema, diarrhea, nausea, and fatigue/asthenia.
Administration is not recommended in patients with advanced systemic mastocytosis whose platelet count is lower than 50 × 109/L.
Avapritinib is a kinase inhibitor that is already approved for the treatment of unresectable or metastatic gastrointestinal stromal tumors harboring PDGFRA exon 18 mutations.
It is a new standard of care for patients with advanced systemic mastocytosis.