S1607 MOLECULAR ANALYSIS IN MAJIC PV CORRELATION WITH CLINICAL ENDPOINTS

Molecular diagnostic criteria of myeloproliferative neoplasms

INTRODUCTION

Myeloproliferative neoplasms (MPN) are a heterogeneous group of clonal hematopoietic stem cell neoplasms characterized by the driver mutations JAK2, CALR, and MPL. These mutations cause constitutive activation of JAK-STAT signaling, which is central to pathogenesis of MPNs. Next-generation sequencing has further expanded the molecular landscape allowing for improved diagnostics, prognostication, and targeted therapy.

AREAS COVERED

This review aims to address current understanding of the molecular diagnosis of MPN not only through improved awareness of the driver mutations but also the disease modifying mutations. In addition, other genetic factors such as clonal hematopoiesis of indeterminate potential (CHIP), order of mutation, and mutation co-occurrence are discussed and how these factors influence disease initiation and ultimately progression. How this molecular information is incorporated into risk stratification models allowing for earlier intervention and targeted therapy in the future will be addressed further.

EXPERT OPINION

The genomic landscape of the MPN has evolved in the last 15 years with integration of next-generation sequencing becoming the gold standard of MPN management. Although diagnostics and prognostication have become more personalized, additional studies are required to translate these molecular findings into targeted therapy therefore improving patient outcomes.

Polycythemia Vera (PV): Update on Emerging Treatment Options

Polycythemia Vera (PV) is a chronic myeloproliferative neoplasm characterized by exuberant red cell production leading to a broad range of symptoms that compromise quality of life and productivity of patients. PV reduces survival expectation, primarily due to thrombotic events, transformation to blast phase and post-PV myelofibrosis or to development of second cancers, which are associates with poor prognosis. Current therapeutic first line recommendations based on risk adapted classification divided patients into two groups, according to age (< or >60 years) and presence of prior thrombotic events. Low-risk patients (age <60 years and no prior history of thrombosis) should be treated with aspirin (81-100 mg/d) and phlebotomy, to maintain hematocrit <45%. High-risk patients (age >60 years and/or prior history of thrombosis), in addition to aspirin and phlebotomies, should receive cytoreductive therapy in order to reduce thrombotic risk. Nowadays hydroxyurea still remains the cytoreductive agent of first choice, reserving Interferon to young patients or childbearing women. During the last years, ruxolitinib emerged as a new treatment in PV patients, as second line therapy: it appeared especially effective in patients with severe pruritus, symptomatic splenomegaly, or post-PV myelofibrosis symptoms. Currently, in PV treatment, several molecules have been tested or are under investigation. At present, the drug that has shown the most encouraging results is givinostat.

Ruxolitinib-Associated Infections in Polycythemia Vera: Review of the Literature, Clinical Significance, and Recommendations

Simple Summary

Polycythemia vera (PV) is a chronic blood disease characterized by elevated red blood cells and splenomegaly. About 98% of all PV patients harbor the JAK2 mutation. Ruxolitinib (RUX), a JAK1/JAK2 inhibitor, received approval as a second-line indication in PV patients who are resistant or intolerant to standard therapy hydroxyurea in both the United States (2014) and Europe (2015). In the studies relevant to approval, RUX achieved excellent PV control. Due to its mechanism of action, RUX also has immunosuppressive effects. As expected, an increased rate of infection was observed in clinical studies and in practical application. In this overview, we have compiled all previous literature references on RUX and infections in PV. However, apart from a few individual cases with special infections and an increased rate of zoster infections, there are no exceptional high infection problems. Recommendations are given on how infections in RUX treated PV patients can be avoided.

Abstract

Ruxolitinib (RUX), a JAK1/JAK2 inhibitor, is approved for second-line therapy in patients with polycythemia vera (PV) who are resistant or intolerant to hydroxyurea. Due to the immunomodulatory and immunosuppressive effect of RUX, there is an increased susceptibility to infections. However, an increased risk of infection is inherent to even untreated myeloproliferative neoplasms (MPN). To obtain more information on the clinical significance of RUX-associated infections in PV, we reviewed the available literature. There is no evidence-based approach to managing infection risks. Most data on RUX-associated infections are available for MF. In all studies, the infection rates in the RUX and control groups were fairly similar, with the exception of infections with the varicella zoster virus (VZV). However, individual cases of bilateral toxoplasmosis retinitis, disseminated molluscum contagiosum, or a mycobacterium tuberculosis infection or a hepatitis B reactivation are reported. A careful assessment of the risk of infection for PV patients is required at the initial presentation and before the start of RUX. Screening for hepatitis B is recommended in all patients. The risk of RUX-associated infections is lower with PV than with MF, but compared to a normal population there is an increased risk of VZV infection. However, primary VZV prophylaxis for PV patients is not recommended, while secondary prophylaxis can be considered individually. As early treatment is most effective for VZV, patients should be properly informed and trained to seek medical advice immediately if cutaneous signs of VZV develop. Vaccination against influenza, herpes zoster, and pneumococci should be considered in all PV patients at risk of infection, especially if RUX treatment is planned. Current recommendations do not support adjusting or discontinuing JAK inhibition in MPN patients to reduce the risk of COVID-19.