Citations

Purpose of review To describe an algorithm-based approach, whenever available, to the diagnosis, the risk stratification criteria informing therapy and the current management of polycythemia vera and essential thrombocythemia. Recent findings Description of recurrent genetic abnormalities in driver genes, including Janus Kinase 2 (JAK2), myeloproliferative leukemia and calreticulin, a better appreciation of the key diagnostic role of bone marrow features, results of large epidemiologic studies and a few but landmark controlled clinical trials produced in the last decade, all resulted in a reappraisal of the approach to polycythemia vera and essential thrombocythemia. Summary The revised 2017 WHO classification of polycythemia vera and essential thrombocythemia allows early diagnosis and accurate distinction from other chronic myeloproliferative neoplasms, particulary prefibrotic myelofibrosis. The prognostic value of selected mutations is being appreciated and JAK2V617F mutation is currently incorporated as risk variable in prognostic system for essential thrombocythemia. Risk-adjusted stratification is used to select therapeutic approaches that include target agents. However, there is not yet a curative approach to these hematologic neoplasms, and although their management has much improved in the last decades, the associated morbidity and mortality remains significant and may be worsened by toxicities of therapeutic agents. Therefore, several clinically relevant endpoints remain unmet.

Abstract The 2013 discovery of calreticulin ( CALR ) mutations in myeloproliferative neoplasms was attended by their association with longer survival in primary myelofibrosis (PMF). Subsequent studies have suggested prognostic distinction between type 1/like and type 2/like CALR mutations and detrimental effect from triple‐negative mutational status. Among 709 Mayo Clinic patients with PMF, 467 (66%) harbored JAK2 , 112 (16%) CALR type 1/like, 24 (3.4%) CALR type 2/like, 38 (5.4%) MPL mutations and 68 (10%) were triple‐negative. Survival was longer with type 1/like CALR , compared to JAK2 (HR 2.6, 95% CI 1.9‐3.5), type 2/like CALR (HR 2.5, 95% CI 1.4‐4.5), MPL (HR 1.8, 95% CI 1.1‐2.9) and triple‐negative mutational status (HR 2.4, 95% CI 1.6‐3.6), but otherwise similar between the non‐type 1/like CALR mutational states ( P = .41). In multivariable analysis, the absence of type 1/like CALR ( P < .001; HR 2, 95% CI 1.4‐2.7), presence of ASXL1 / SRSF2 mutations ( P < .001; HR 1.9, 95% CI 1.5‐2.4) and DIPSS‐plus ( P < .001) were each predictive of inferior survival. Furthermore, among 210 patients with ASXL1 / SRSF2 mutations, survival was significantly longer in the presence vs. absence of type 1/like CALR mutations (median 5.8 vs. 2.9 years; P < .001). Triple‐negative status did not disclose additional prognostic information for overall or leukemia‐free survival. The observations regarding the prognostic distinction between CALR mutation variants were validated in an external cohort of 386 patients from the University of Florence Careggi hospital. We conclude that type 1/like CALR mutations in PMF not only predict superior survival, but also partially amend the detrimental effect of high molecular risk mutations.

AbstractTherapy related myeloid neoplasms (t‐MN) including therapy related myelodysplastic syndromes (t‐MDS) and acute myeloid leukemia (t‐AML) are associated with aggressive disease biologies and poor outcomes. In this large (n = 497) and informative (inclusive of molecular and cytogenetic information) chronic myelomonocytic leukemia (CMML) patient cohort, we demonstrate key biological insights and an independent prognostic impact for t‐CMML. T‐CMML was diagnosed in 9% of patients and occurred approximately 7 years after exposure to prior chemotherapy and/or radiation therapy. In comparison to de novo CMML, t‐CMML patients had higher LDH levels, higher frequency of karyotypic abnormalities and had higher risk cytogenetic stratification. There were no differences in the distribution of gene mutations and unlike t‐MDS/AML, balanced chromosomal translocations, abnormalities of chromosome 11q23 (1%) and Tp53 mutations (<2%) were uncommon. Molecularly integrated CMML prognostic models were not effective in risk stratifying t‐CMML patients and responses to hypomethylating agents were dismal with no complete responses. Median overall (OS) and leukemia free survival (LFS) was shorter for t‐CMML in comparison to d‐CMML (Median OS 10.9 vs 26 months and median LFS 50 vs 127 months) and t‐CMML independently and adversely impacted OS (P = .0001 HR 2.1 95% CI 1.4‐3.0). This prognostic impact was retained in the context of the Mayo Molecular Model (P = .001, HR 2.4, 95% CI 1.5‐3.7) and the GFM prognostic model (P < .0001, HR 2.15, 95% CI 1.5‐3.7). In summary, we highlight the unique genetics and independent prognostic impact of t‐CMML, warranting its inclusion as a separate entity in the classification schema for both CMML and t‐MN.