(PATHFINDER) Study to Evaluate Efficacy and Safety of Avapritinib (BLU-285), A Selective KIT Mutation-targeted Tyrosine Kinase Inhibitor, in Patients With Advanced Systemic Mastocytosis
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ClinicalTrials.gov Identifier: NCT03580655 |
Recruitment Status :
Active, not recruiting
First Posted : July 9, 2018
Last Update Posted : August 2, 2023
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Condition or disease | Intervention/treatment | Phase |
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Advanced Systemic Mastocytosis Aggressive Systemic Mastocytosis Systemic Mastocytosis With an Associated Hematologic Neoplasm Mast Cell Leukemia | Drug: Avapritinib | Phase 2 |
Study Type : | Interventional (Clinical Trial) |
Estimated Enrollment : | 103 participants |
Allocation: | N/A |
Intervention Model: | Single Group Assignment |
Masking: | None (Open Label) |
Primary Purpose: | Treatment |
Official Title: | An Open-label, Single Arm, Phase 2 Study to Evaluate Efficacy and Safety of Avapritinib (BLU-285), A Selective KIT Mutation-targeted Tyrosine Kinase Inhibitor, in Patients With Advanced Systemic Mastocytosis |
Actual Study Start Date : | November 21, 2018 |
Estimated Primary Completion Date : | January 31, 2026 |
Estimated Study Completion Date : | January 31, 2026 |

Arm | Intervention/treatment |
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Experimental: Avapritinib
Avapritinib will be administered as an immediate release tablet, orally, continuously, in 28-day cycles
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Drug: Avapritinib
Avapritinib tablet
Other Name: BLU-285 |
- Objective response rate (ORR) based on modified International Working Group-Myeloproliferative Neoplasms Research and Treatment and European Competence Network on Mastocytosis (IWG-MRT-ECNM) response criteria [ Time Frame: 10 Months ]
- Mean Change from Baseline in Advanced Systemic Mastocytosis-Symptom Assessment Form (AdvSM-SAF) Total Symptom Score [ Time Frame: 10 Months ]0 - 80 points (higher value represents worse symptom outcomes)
- Objective response rate [ Time Frame: Approximately 4 years after the first subjected enrolled ]Including morphologic complete remission (mCR), morphologic CR with partial recovery of peripheral blood (mCRh), and morphologic partial remission (mPR) based on Pure Pathologic Response
- Time-to-response (TTR) [ Time Frame: 10 Months ]Months
- Duration of Response (DOR) [ Time Frame: 10 Months ]Months
- Progression-free Survival (PFS) [ Time Frame: 10 Months ]Months
- Overall Survival (OS) [ Time Frame: 10 Months ]Months
- Changes in bone marrow mast cells [ Time Frame: 10 Months ]percentage
- Change in serum tryptase [ Time Frame: 10 Months ]ng/mL
- Change in V-kit Hardy-Zuckerman 4 feline sarcoma viral oncogene homolog aspartate 816 valine (KIT D816V) mutation burden [ Time Frame: 10 Months ]percentage
- Change in liver volume by imaging [ Time Frame: 10 Months ]mL
- Change in spleen volume by imaging [ Time Frame: 10 Months ]mL
- Clinical benefit based on modified IWG-MRT-ECNM consensus criteria [ Time Frame: 10 Months ]
- Change in PGIS [ Time Frame: 10 Months ]0 - 10 points (higher value represents worse symptom outcomes)
- Change in EORTC QLQ-C30 [ Time Frame: 10 Months ]0 - 100 points (lower value represents worse quality of life)
- Safety of Avapritinib as assessed by incidence of adverse events [ Time Frame: 10 Months ]CTCAE version 4.0
- Area Under Curve (0 to Tau) for Avapritinib [ Time Frame: 4 Months ]h•ng/mL

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.
Ages Eligible for Study: | 18 Years and older (Adult, Older Adult) |
Sexes Eligible for Study: | All |
Accepts Healthy Volunteers: | No |
Key Inclusion Criteria:
- Patient must have a diagnosis of aggressive systemic mastocytosis (ASM), systemic mastocytosis with an associated hematologic neoplasm (SM-AHN) or mast cell leukemia (MCL) based on World Health Organization diagnostic criteria. Before enrollment, the Study Steering Committee must confirm the diagnosis of AdvSM (based on Central Pathology Laboratory assessment of bone marrow).
- Patient must have a serum tryptase ≥ 20 ng/mL.
- Patient must have Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0 to 3.
Key Exclusion Criteria:
- Patient has received prior treatment with avapritinib.
- Patient has received any cytoreductive therapy (including midostaurin and other TKIs, hydroxyurea, azacitidine) or an investigational agent less than 14 days, and for cladribine, interferon alpha, pegylated interferon and any antibody therapy (eg, brentuximab vedotin) less than 28 days before obtaining screening BM biopsy for this study.
- Patient has eosinophilia and known positivity for the FIP1L1 PGDFRA fusion, unless the patient has demonstrated relapse or PD on prior imatinib therapy. Patients with eosinophilia (> 1.5 × 10^9/L), who do not have a detectable KIT D816 mutation, must be tested for a PDGFRA fusion mutation by fluorescence in situ hybridization (FISH) or polymerase chain reaction (PCR).
- Patient has history of another primary malignancy that has been diagnosed or required therapy within 3 years before the first dose of study drug. The following are exempt from the 3-year limit: completely resected basal cell and squamous cell skin cancer, curatively treated localized prostate cancer, and completely resected carcinoma in situ of any site.
- Patient has a QT interval corrected using Fridericia's formula (QTcF) > 480 msec.
- Patient has a known risk or recent history (12 months before the first dose of study drug) of intracranial bleeding (eg, brain aneurysm, concomitant vitamin K antagonist use).
- Platelet count < 50,000/μL (within 4 weeks of the first dose of study drug) or receiving platelet transfusion(s).
- Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) >3 x the upper limit of normal (ULN); no restriction if due to suspected liver infiltration by mast cells.
- Bilirubin >1.5 × ULN; no restriction if due to suspected liver infiltration by mast cells or Gilbert's disease. (In the case of Gilbert's disease, a direct bilirubin >2 × ULN would be an exclusion.)
- Estimated glomerular filtration rate (eGFR) < 30 mL/min/1.73m2 or creatinine > 1.5 × ULN.
- Patient has a primary brain malignancy or metastases to the brain.
- Patient has a history of a seizure disorder (eg, epilepsy) or requirement for antiseizure medication.

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03580655

Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: | Blueprint Medicines Corporation |
ClinicalTrials.gov Identifier: | NCT03580655 |
Other Study ID Numbers: |
BLU-285-2202 2017-004836-13 ( EudraCT Number ) |
First Posted: | July 9, 2018 Key Record Dates |
Last Update Posted: | August 2, 2023 |
Last Verified: | August 2023 |
Studies a U.S. FDA-regulated Drug Product: | Yes |
Studies a U.S. FDA-regulated Device Product: | No |
Mastocytosis Mastocytosis, Systemic Hematologic Neoplasms Leukemia, Mast-Cell Neoplasms, Connective Tissue Neoplasms, Connective and Soft Tissue Neoplasms by Histologic Type Neoplasms |
Mast Cell Activation Disorders Immune System Diseases Neoplasms by Site Hematologic Diseases Leukemia Leukemia, Myeloid, Acute Leukemia, Myeloid |