Philadelphia-Negative Myeloproliferative Neoplasms Around the COVID-19 Pandemic

A Review of Hematological Complications and Treatment in COVID-19

COVID-19, caused by SARS-CoV-2, and its variants have spread rapidly across the globe in the past few years, resulting in millions of deaths worldwide. Hematological diseases and complications associated with COVID-19 severely impact the mortality and morbidity rates of patients; therefore, there is a need for oversight on what pharmaceutical therapies are prescribed to hematologically at-risk patients. Thrombocytopenia, hemoglobinemia, leukopenia, and leukocytosis are all seen at increased rates in patients infected with COVID-19 and become more prominent in patients with severe COVID-19. Further, COVID-19 therapeutics may be associated with hematological complications, and this became more important in immunocompromised patients with hematological conditions as they are at higher risk of hematological complications after treatment. Thus, it is important to understand and treat COVID-19 patients with underlying hematological conditions with caution. Hematological changes during COVID-19 infection and treatment are important because they may serve as biomarkers as well as to evaluate the treatment response, which will help in changing treatment strategies. In this literature review, we discuss the hematological complications associated with COVID-19, the mechanisms, treatment groups, and adverse effects of commonly used COVID-19 therapies, followed by the hematological adverse events that could arise due to therapeutic agents used in COVID-19.

Splenomegaly in patients with primary or secondary myelofibrosis who are candidates for allogeneic hematopoietic cell transplantation: a Position Paper on behalf of the Chronic Malignancies Working Party of the EBMT

Splenomegaly is a hallmark of myelofibrosis, a debilitating haematological malignancy for which the only curative option is allogeneic haematopoietic cell transplantation (HCT). Considerable splenic enlargement might be associated with a higher risk of delayed engraftment and graft failure, increased non-relapse mortality, and worse overall survival after HCT as compared with patients without significantly enlarged splenomegaly. Currently, there are no standardised guidelines to assist transplantation physicians in deciding optimal management of splenomegaly before HCT. Therefore, the aim of this Position Paper is to offer a shared position statement on this issue. An international group of haematologists, transplantation physicians, gastroenterologists, surgeons, radiotherapists, and radiologists with experience in the treatment of myelofibrosis contributed to this Position Paper. The key issues addressed by this group included the assessment, prevalence, and clinical significance of splenomegaly, and the need for a therapeutic intervention before HCT for the control of splenomegaly. Specific scenarios, including splanchnic vein thrombosis and COVID-19, are also discussed. All patients with myelofibrosis must have their spleen size assessed before allogeneic HCT. Myelofibrosis patients with splenomegaly measuring 5 cm and larger, particularly when exceeding 15 cm below the left costal margin, or with splenomegaly-related symptoms, could benefit from treatment with the aim of reducing the spleen size before HCT. In the absence of, or loss of, response, patients with increasing spleen size should be evaluated for second-line options, depending on availability, patient fitness, and centre experience. Splanchnic vein thrombosis is not an absolute contraindication for HCT, but a multidisciplinary approach is warranted. Finally, prevention and treatment of COVID-19 should adhere to standard recommendations for immunocompromised patients.

Treatment and Clinical Endpoints in Polycythemia Vera: Seeking the Best Obtainable Version of the Truth

Polycythemia vera (PV) is a Philadelphia chromosome-negative myeloproliferative neoplasm driven by the JAK2 V617F (or rarely exon 12) mutation. Its natural history can extend over a few decades, and therefore treatment planning is predicated on continual re-assessment of traditional risk features (age, prior thrombosis) to evaluate the need for cytoreduction besides foundational therapy with low-dose aspirin and stringent phlebotomy. Shorter- and longer-term patient goals should be considered in light of several variables such as co-morbid conditions (especially cardiovascular risk factors), disease symptoms, and the risk-benefit profile of available drugs. While hydroxyurea has been the pro forma choice of cytoreduction for many practitioners over the last half-century, the more recent regulatory approvals of ruxolitinib and ropeginterferon-alfa-2b, based on phase 3 randomized trials, highlight an expanding portfolio of active drugs. Obtaining high-level evidence for short-term clinical trial endpoints such as hematocrit control, symptom burden/quality of life, splenomegaly, and JAK2 V617F allele burden lies within the timeline of most studies. However, in many cases, it may not be possible to adequately power trials to capture significant differences in the typically low event rates of thrombosis, as well as longer-horizon endpoints such as evolution to myelofibrosis and acute myeloid leukemia, and survival. This Perspective highlights the challenges of addressing these data gaps and outstanding questions in the emerging treatment landscape of PV.

Immune Dysregulation and Infectious Complications in MPN Patients Treated With JAK Inhibitors

BCR-ABL1-negative myeloproliferative neoplasms are burdened by a reduced life expectancy mostly due to an increased risk of thrombo-hemorrhagic events, fibrotic progression/leukemic evolution, and infectious complications. In these clonal myeloid malignancies, JAK2V617F is the main driver mutation, leading to an aberrant activation of the Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling pathway. Therefore, its inhibition represents an attractive therapeutic strategy for these disorders. Several JAK inhibitors have entered clinical trials, including ruxolitinib, the first JAK1/2 inhibitor to become commercially available for the treatment of myelofibrosis and polycythemia vera. Due to interference with the JAK-STAT pathway, JAK inhibitors affect several components of the innate and adaptive immune systems such as dendritic cells, natural killer cells, T helper cells, and regulatory T cells. Therefore, even though the clinical use of these drugs in MPN patients has led to a dramatic improvement of symptoms control, organ involvement, and quality of life, JAK inhibitors–related loss of function in JAK-STAT signaling pathway can be a cause of different adverse events, including those related to a condition of immune suppression or deficiency. This review article will provide a comprehensive overview of the current knowledge on JAK inhibitors’ effects on immune cells as well as their clinical consequences, particularly with regards to infectious complications.