Absence of canonical MPN-driver mutations (JAK2V617F, CALR, MPL) with some cases harboring rare non-canonical variants or high molecular risk mutations (ASXL1, SRSF2, U2AF1Q157)
Target Population
Patients diagnosed with chronic phase triple-negative primary myelofibrosis
Care Setting
Specialized hematology/oncology centers with molecular diagnostic capabilities
Key Highlights
Triple-negative PMF accounts for approximately 8.5% of chronic phase PMF cases and is characterized by absence of JAK2, CALR, and MPL mutations using sensitive institutional assays.
Independent risk factors for overall survival in triple-negative PMF include age >65 years, hemoglobin <10 g/dL, leukocyte count >25 × 10^9/L, peripheral blood blasts ≥1%, and unfavorable karyotype.
High molecular risk mutations (ASXL1, SRSF2, U2AF1Q157) and unfavorable karyotype cluster differently in triple-negative versus JAK2-mutated PMF and are associated with worse overall and leukemia-free survival.
Guideline-Based Recommendations
Diagnosis
Use institutional mutation screening methods with high analytic sensitivity to exclude JAK2V617F, CALR, and MPL mutations for triple-negative PMF classification.
Confirm diagnosis according to International Consensus Classification criteria with central pathology review.
Perform cytogenetic analysis examining at least 10 metaphases to classify karyotype as favorable or unfavorable.
Management
Consider prognostic scoring systems such as DIPSS and DIPSS-plus incorporating clinical and cytogenetic variables to guide risk stratification.
Monitor for anemia severity and leukocytosis as these impact prognosis.
Allogenic stem cell transplantation (ASCT) may be considered, noting censoring of survival analyses at ASCT.
Monitoring & Follow-up
Regular assessment of blood counts including hemoglobin, leukocyte, and platelet counts.
Monitor peripheral blood blast percentage to detect disease progression.
Surveillance for leukemic transformation given observed rates (~14% in triple-negative PMF).
Risks
Increased mortality risk associated with age >65, anemia, leukocytosis, peripheral blasts, and unfavorable karyotype.
High molecular risk mutations confer worse overall and leukemia-free survival.
Unfavorable karyotype has a significant negative impact on survival in triple-negative PMF but not in JAK2-mutated PMF.
Patient & Prescribing Data
Patients with chronic phase triple-negative primary myelofibrosis identified via molecular testing
Survival outcomes and risk stratification differ from JAK2-mutated PMF; treatment decisions should consider unique prognostic factors including karyotype and high molecular risk mutations.
Clinical Best Practices
Employ sensitive molecular assays to accurately classify PMF mutation status.
Incorporate cytogenetic and molecular risk factors into prognostic models for personalized patient management.
Exclude patients with accelerated phase PMF (≥10% blasts) from chronic phase analyses and management protocols.
Use multivariable analyses to identify independent risk factors guiding clinical decision-making.
Consider the differential impact of unfavorable karyotype in triple-negative versus JAK2-mutated PMF when counseling patients.
by Yassin A. Bashir, Ahmed A. Abdelrheem, Maymona Abdelmagid, Kaaren K. Reichard, Rong He, Cinthya J. Zepeda Mendoza, Animesh Pardanani, Naseema Gangat, Ayalew Tefferi
