Ruxolitinib-associated infections: A systematic review and meta-analysis

Vaccination of patients with haematological malignancies who did not have transplantations: guidelines from the 2017 European Conference on Infections in Leukaemia (ECIL 7)

Patients with haematological malignancies are at high risk of infection because of various mechanisms of humoral and cell-mediated immune deficiencies, which mainly depend on underlying disease and specific therapies. Some of these infections are vaccine preventable. However, these malignancies are different from each other, and the treatment approaches are diverse and rapidly evolving, so it is difficult to have a common programme for vaccination in a haematology ward. Additionally, because of insufficient training about the topic, vaccination is an area often neglected by haematologists, and influenced by cultural differences, even among health-care workers, in compliance to vaccines. Several issues are encountered when addressing vaccination in haematology: the small size of the cohorts that makes it difficult to show the clinical benefits of vaccination, the subsequent need to rely on biological parameters, their clinical pertinence not being established in immunocompromised patients, scarcity of clarity on the optimal timing of vaccination in complex treatment schedules, and the scarcity of data on long-term protection in patients receiving treatments. Moreover, the risk of vaccine-induced disease with live-attenuated vaccines strongly limits their use. Here we summarise guidelines for patients without transplantations, and address the issue by the haematological group-myeloid and lymphoid-of diseases, with a special consideration for children with acute leukaemia.

Invasive aspergillosis manifesting as retinal necrosis in a patient treated with ruxolitinib

A 30 year-old man with acute myeloblastic leukaemia and secondary myelodysplastic syndrome developed graft-versus-host disease. The patient was treated with ruxolitinib. After being treated for 3 months with ruxolitinib, an inhibitor of Janus kinase, he developed Aspergillus retinal necrosis resistant to common treatment. Treatment with Janus kinase inhibitors may lead to an increased incidence of opportunistic infections. Janus kinase inhibitor administration may result in poor treatment efficacy.

Classical Philadelphia-negative myeloproliferative neoplasms: focus on mutations and JAK2 inhibitors

Classical Philadelphia- negative myeloproliferative neoplasms (MPNs) encompass three main myeloid malignancies: polycythemia vera (PV), essential thrombocythemia (ET), and myelofibrosis (MF). Phenotype-driver mutations in Janus kinase 2 (JAK2), calreticulin (CALR), and myeloproliferative leukemia virus oncogene (MPL) genes are mutually exclusive and occur with a variable frequency. Driver mutations influence disease phenotype and prognosis. PV patients with JAK2 exon 14 mutation do not differ in number of thrombotic events, risk of leukemic and fibrotic transformation, and overall survival to those with JAK2 exon 12 mutation. Type 2-like CALR-mutated ET patients have lower risk of thrombosis if compared with those carrying JAK2 or type 1-like CALR mutation. For ET, overall survival is comparable between patients with JAK2 and either type 1-like and type 2-like CALR mutations. For MF, better OS is demonstrated for patients harboring a type 1-like CALR mutation than those with type 2-like CALR or JAK2. The discovery of driver mutations in MPNs has prompted the development of molecularly targeted therapy. Among JAK2 inhibitors, ruxolitinib (RUX) has been approved for (1) treatment of intermediate-2 and high-risk MF and (2) PV patients who are resistant to or intolerant to hydroxyurea. RUX reduces spleen size and alleviates disease symptoms in a proportion of MF patients. RUX in MF leads to prolonged survival and reduces risk of death. RUX controls hematocrit, reduces spleen size and alleviates symptoms in PV. Adverse events of RUX are moderate, however, its long-term use may be associated with opportunistic infections. Trials with other JAK2 inhibitors are ongoing.

How I treat myelofibrosis after failure of JAK inhibitors

The introduction of JAK inhibitors, leading to regulatory approval of ruxolitinib, represents a major therapeutic advance in myelofibrosis (MF). Most patients experience reduction in splenomegaly and improved quality of life from symptom improvement. It is a paradox, however, that, despite inhibition of signaling downstream of disease-related driver mutations, JAK inhibitor treatment is not associated with consistent molecular or pathologic responses in MF. Furthermore, there are important limitations to JAK inhibitor therapy including development of dose-limiting cytopenias and/or nonhematological toxicities such as neuropathy or opportunistic infections. Over half of the patients discontinue treatment within 3 years of starting treatment. Although data are sparse, clinical outcome after JAK inhibitor "failure" is likely poor; consequently, it is important to understand patterns of failure to select appropriate salvage treatment(s). An algorithmic approach, particularly one that incorporates cytogenetics/molecular data, is most helpful in selecting stem cell transplant candidates. Treatment of transplant-ineligible patients relies on a problem-based approach that includes use of investigational drugs, or consideration of splenectomy or radiotherapy. Data from early phase ruxolitinib combination studies, despite promising preclinical data, have not shown clear benefit over monotherapy thus far. Development of effective treatment strategies for MF patients failing JAK inhibitors remains a major unmet need.

Momelotinib therapy for myelofibrosis: a 7-year follow-up

One-hundred Mayo Clinic patients with high/intermediate-risk myelofibrosis (MF) received momelotinib (MMB; JAK1/2 inhibitor) between 2009 and 2010, as part of a phase 1/2 trial (NCT00935987); 73% harbored JAK2 mutations, 16% CALR, 7% MPL, 44% ASXL1, and 18% SRSF2. As of July 2017, MMB was discontinued in 91% of the patients, after a median treatment duration of 1.4 years. Grade 3/4 toxicity included thrombocytopenia (34%) and liver/pancreatic test abnormalities (<10%); grade 1/2 peripheral neuropathy occurred in 47%. Clinical improvement (CI) occurred in 57% of patients, including 44% anemia and 43% spleen response. CI was more likely to occur in ASXL1-unmutated patients (66% vs 44%) and in those with <2% circulating blasts (66% vs 42%). Response was more durable in the presence of CALR type 1/like and absence of very high-risk karyotype. In multivariable analysis, absence of CALR type 1/like (HR 3.0; 95% CI 1.2-7.6) and presence of ASXL1 (HR 1.9; 95% CI 1.1-3.2) or SRSF2 (HR 2.4, 95% CI 1.3-4.5) mutations adversely affected survival. SRSF2 mutations (HR 4.7, 95% CI 1.3-16.9), very high-risk karyotype (HR 7.9, 95% CI 1.9-32.1), and circulating blasts ≥2% (HR 3.9, 95% CI 1.4-11.0) predicted leukemic transformation. Post-MMB survival (median 3.2 years) was not significantly different than that of a risk-matched MF cohort not receiving MMB.