Fatal Disseminated Tuberculosis during Treatment with Ruxolitinib Plus Prednisolone in a Patient with Primary Myelofibrosis: A Case Report and Review of the Literature

Momelotinib (JAK1/JAK2/ACVR1 inhibitor): mechanism of action, clinical trial reports, and therapeutic prospects beyond myelofibrosis

Janus kinase (JAK) 2 inhibitors are now part of the therapeutic armamentarium for primary and secondary myelofibrosis (MF). Patients with MF endure shortened survival and poor quality of life. Allogeneic stem cell transplantation (ASCT) is currently the only treatment modality in MF with the potential to cure the disease or prolong survival. By contrast, current drug therapy in MF targets quality of life and does not modify the natural history of the disease. The discovery of JAK2 and other JAK-STAT activating mutations (i.e., CALR and MPL) in myeloproliferative neoplasms, including MF, has facilitated the development of several JAK inhibitors that are not necessarily specific to the oncogenic mutations themselves but have proven effective in countering JAK-STAT signaling, resulting in suppression of inflammatory cytokines and myeloproliferation. This non-specific activity resulted in clinically favorable effects on constitutional symptoms and splenomegaly and, consequently, approval by the Food and Drug Administration (FDA) of three small molecule JAK inhibitors: ruxolitinib, fedratinib, and pacritinib. A fourth JAK inhibitor, momelotinib, is poised for FDA approval soon and has been shown to provide additional benefit in alleviating transfusion-dependent anemia in MF. The salutary effect of momelotinib on anemia has been attributed to inhibition of activin A receptor, type 1 (ACVR1) and recent information suggests a similar effect from pacritinib. ACRV1 mediates SMAD2/3 signaling which contributes to upregulation of hepcidin production and iron-restricted erythropoiesis. Targeting ACRV1 raises therapeutic prospects in other myeloid neoplasms associated with ineffective erythropoiesis, such as myelodysplastic syndromes with ring sideroblasts or SF3B1 mutation, especially those with co-expression of a JAK2 mutation and thrombocytosis.

Recent progress of JAK inhibitors for hematological disorders

JAK inhibitors are important therapeutic options for hematological disorders, especially myeloproliferative neoplasms. Ruxolitinib, the first JAK inhibitor approved for clinical use, improves splenomegaly and ameliorates constitutional symptoms in both myelofibrosis and polycythemia vera patients. Ruxolitinib is also useful for controlling hematocrit levels in polycythemia vera patients who were inadequately controlled by conventional therapies. Furthermore, pretransplantation use of ruxolitinib may improve the outcome of allo-hematopoietic stem cell transplantation in myelofibrosis. In contrast to these clinical merits, evidence of the disease-modifying action of ruxolitinib, i.e., reduction of malignant clones or improvement of bone marrow pathological findings, is limited, and many myelofibrosis patients discontinued ruxolitinib due to adverse events or disease progression. To overcome these limitations of ruxolitinib, several new types of JAK inhibitors have been developed. Among them, fedratinib was proven to provide clinical merits even in patients who were resistant or intolerant to ruxolitinib. Pacritinib and momelotinib have shown merits for myelofibrosis patients with thrombocytopenia or anemia, respectively. In addition to treatment for myeloproliferative neoplasms, recent studies have demonstrated that JAK inhibitors are novel and attractive therapeutic options for corticosteroid-refractory acute as well as chronic graft versus host disease.

Ruxolitinib inhibits cytokine production by human lung macrophages without impairing phagocytic ability

Background: The Janus kinase (JAK) 1/2 inhibitor ruxolitinib has been approved in an indication of myelofibrosis and is a candidate for the treatment of a number of inflammatory or autoimmune diseases. We assessed the effects of ruxolitinib on lipopolysaccharide (LPS)- and poly (I:C)-induced cytokine production by human lung macrophages (LMs) and on the LMs’ phagocytic activity.

Methods: Human LMs were isolated from patients operated on for lung carcinoma. The LMs were cultured with ruxolitinib (0.5 × 10−7 M to 10–5 M) or budesonide (10–11 to 10–8 M) and then stimulated with LPS (10 ng·ml−1) or poly (I:C) (10 μg·ml−1) for 24 h. Cytokines released by the LMs into the supernatants were measured using ELISAs. The phagocytosis of labelled bioparticles was assessed using flow cytometry.

Results: Ruxolitinib inhibited both the LPS- and poly (I:C)-stimulated production of tumor necrosis factor alpha, interleukin (IL)-6, IL-10, chemokines CCL2, and CXCL10 in a concentration-dependent manner. Ruxolitinib also inhibited the poly (I:C)- induced (but not the LPS-induced) production of IL-1ß. Budesonide inhibited cytokine production more strongly than ruxolitinib but failed to mitigate the production of CXCL10. The LMs’ phagocytic activity was not impaired by the highest tested concentration (10–5 M) of ruxolitinib.

Conclusion: Clinically relevant concentrations of ruxolitinib inhibited the LPS- and poly (I:C)-stimulated production of cytokines by human LMs but did not impair their phagocytic activity. Overall, ruxolitinib’s anti-inflammatory activities are less intense than (but somewhat different from) those of budesonide—particularly with regard to the production of the corticosteroid-resistant chemokine CXCL-10. Our results indicate that treatment with a JAK inhibitor might be a valuable anti-inflammatory strategy in chronic obstructive pulmonary disease, Th1-high asthma, and both viral and non-viral acute respiratory distress syndromes (including coronavirus disease 2019).

Fatal Disseminated Tuberculosis and Concurrent Disseminated Cryptococcosis in a Ruxolitinib-treated Patient with Primary Myelofibrosis: A Case Report and Literature Review

Ruxolitinib, a Janus kinase inhibitor, improves symptoms in patients with myelofibrosis. However, its association with the development of opportunistic infections has been a concern. We herein report a 71-year-old man with primary myelofibrosis who developed disseminated tuberculosis and concurrent disseminated cryptococcosis during ruxolitinib treatment. We also reviewed the literature on disseminated tuberculosis and/or cryptococcosis associated with ruxolitinib treatment. This is the first case of disseminated tuberculosis and concurrent disseminated cryptococcosis during treatment with ruxolitinib. We therefore suggest considering not only disseminated tuberculosis but also cryptococcosis in the differential diagnosis of patients with abnormal pulmonary shadows during ruxolitinib treatment.

Myelofibrosis: Genetic Characteristics and the Emerging Therapeutic Landscape

Primary myelofibrosis (PMF) is one of three myeloproliferative neoplasms (MPN) that are morphologically and molecularly inter-related, the other two being polycythemia vera (PV) and essential thrombocythemia (ET). MPNs are characterized by JAK-STAT-activating JAK2, CALR, or MPL mutations that give rise to stem cell-derived clonal myeloproliferation, which is prone to leukemic and, in case of PV and ET, fibrotic transformation. Abnormal megakaryocyte proliferation is accompanied by bone marrow fibrosis and characterizes PMF, while the clinical phenotype is pathogenetically linked to ineffective hematopoiesis and aberrant cytokine expression. Among MPN-associated driver mutations, type 1-like CALR mutation has been associated with favorable prognosis in PMF, while ASXL1, SRSF2, U2AF1-Q157, EZH2, CBL, and K/NRAS mutations have been shown to be prognostically detrimental. Such information has enabled development of exclusively genetic (GIPSS) and clinically integrated (MIPSSv2) prognostic models that facilitate individualized treatment decisions. Allogeneic stem cell transplantation remains the only treatment modality in MF with the potential to prolong survival, whereas drug therapy, including JAK2 inhibitors, is directed mostly at the inflammatory component of the disease and is therefore palliative in nature. Similarly, disease-modifying activity remains elusive for currently available investigational drugs, while their additional value in symptom management awaits controlled confirmation. There is a need for genetic characterization of clinical observations followed by in vitro and in vivo preclinical studies that will hopefully identify therapies that target the malignant clone in MF to improve patient outcomes.

Isolated Nodal TBC Reactivation in a Patient with Post-Thrombocythemia Myelofibrosis Treated with Ruxolitinib: Case Report and Review of the Literature

Ruxolitinib side effects include the most frequent hematological toxicity along with a more recently evidenced immunosuppressive activity, interfering both with the innate and adaptive immunity, and several cases of reactivation of latent infections by opportunistic agents in patients in treatment with ruxolitinib have been published in the last years. Several pathophysiological mechanisms may explain an association between ruxolitinib and opportunistic infections. From what we know, the only case of an isolated lymph node TBC reactivation in a ruxolitinib-treated myelofibrosis (MF) patient was reported by Patil et al. in 2016 [Int J Med Sci Public Health. 2017;6(3):1]. Other 10 cases describing TBC reactivations in MF patients assuming ruxolitinib and successfully treated with 4-drug anti-TBC therapy are available in the literature to date. The case we reported describes an isolated lymph nodal TBC reactivation in a patient with the diagnosis of post-essential thrombocythemia-MF during ruxolitinib treatment after a long course of interferon-a (IFN-α2b) assumed for the previous diagnosis of ET. The case we report teaches that lymphadenopathy with or without constitutional symptoms developing during ruxolitinib therapy should be considered as a possible manifestation of a TBC reactivation in patients with a previous positive TBC-exposure test. In these cases, Ziel-Nielsen testing on urine and sputum has to be performed to rule out infectiousness and eventually isolate the patient. Moreover, previous long-time exposition to IFN-α2b may be related with a higher risk for TBC reactivation in these subset of patients. We encourage reevaluation of the cohorts of patients treated with ruxolitinib in previous and current large prospective studies to study the possible correlation between previous exposition to IFN-α2b and TBC reactivation.

Infectious Risks Associated with Biologics Targeting Janus Kinase-Signal Transducer and Activator of Transcription Signaling and Complement Pathway for Inflammatory Diseases

The recognition of the role of complement and Janus kinase (JAK)-dependent cytokines in the pathogenesis of inflammatory and immune-mediated disorders has revolutionized the treatment of a myriad of rheumatological and inflammatory diseases. C5 inhibitors and Janus kinase inhibitors have emerged as attractive therapeutic options. Because of the blockage of immune pathways, these targeted therapies carry an increased risk of infection. This article reviews the mechanism of action and the approved and off-label indications of the agents with most clinical experience within this drug classes. It discusses the associated risks of infection, proposing screening, prevention, and risk mitigation strategies.

Primary myelofibrosis: 2021 update on diagnosis, risk-stratification and management

DISEASE OVERVIEW

Primary myelofibrosis (PMF) is a myeloproliferative neoplasm (MPN) characterized by stem cell-derived clonal myeloproliferation that is often but not always accompanied by JAK2, CALR, or MPL mutations. Additional disease features include bone marrow reticulin/collagen fibrosis, aberrant inflammatory cytokine expression, anemia, hepatosplenomegaly, extramedullary hematopoiesis (EMH), constitutional symptoms, cachexia, leukemic progression, and shortened survival.

DIAGNOSIS

Bone marrow morphology is the primary basis for diagnosis. Presence of JAK2, CALR, or MPL mutation, expected in around 90% of the patients, is supportive but not essential for diagnosis; these mutations are also prevalent in the closely related MPNs, namely polycythemia vera (PV) and essential thrombocythemia (ET). The 2016 World Health Organization classification system distinguishes "prefibrotic" from "overtly fibrotic" PMF; the former might mimic ET in its presentation. Furthermore, approximately 15% of patients with ET or PV might progress into a PMF-like phenotype (post-ET/PV MF) during their clinical course.

ADVERSE MUTATIONS

SRSF2, ASXL1, and U2AF1-Q157 mutations predict inferior survival in PMF, independent of each other and other risk factors. RAS/CBL mutations predicted resistance to ruxolitinib therapy.

ADVERSE KARYOTYPE

Very high risk abnormalities include -7, inv (3), i(17q), +21, +19, 12p-, and 11q-.

RISK STRATIFICATION

Two new prognostic systems for PMF have recently been introduced: GIPSS (genetically-inspired prognostic scoring system) and MIPSS70+ version 2.0 (MIPSSv2; mutation- and karyotype-enhanced international prognostic scoring system). GIPSS is based exclusively on mutations and karyotype. MIPSSv2 includes, in addition, clinical risk factors. GIPSS features four and MIPSSv2 five risk categories.

RISK-ADAPTED THERAPY

Observation alone is advised for MIPSSv2 "low" and "very low" risk disease (estimated 10-year survival 56%-92%); allogeneic hematopoietic stem cell transplant (AHSCT) is the preferred treatment for "very high" and "high" risk disease (estimated 10-year survival 0%-13%); treatment-requiring patients with intermediate-risk disease (estimated 10-year survival 30%) are best served by participating in clinical trials. In non-transplant candidates, conventional treatment for anemia includes androgens, prednisone, thalidomide, and danazol; for symptomatic splenomegaly, hydroxyurea and ruxolitinib; and for constitutional symptoms, ruxolitinib. Fedratinib, another JAK2 inhibitor, has now been FDA-approved for use in ruxolitinib failures. Splenectomy is considered for drug-refractory splenomegaly and involved field radiotherapy for non-hepatosplenic EMH and extremity bone pain.

NEW DIRECTIONS

A number of new agents, alone or in combination with ruxolitinib, are currently under investigation for MF treatment (ClinicalTrials.gov); preliminary results from some of these clinical trials were presented at the 2020 ASH annual meeting and highlighted in the current document.

Tuberculosis in Patients with Primary Myelofibrosis During Ruxolitinib Therapy: Case Series and Literature Review

Background

The selective Janus-activated kinase inhibitor ruxolitinib (rux) is now widely used to treat myelofibrosis and polycythemia vera due to its remarkable effect of reducing splenomegaly and improving constitutional symptoms. With opportunistic infections secondary to rux constantly reported; however, an increasing number of studies have begun to investigate the mechanism and underlying immunosuppressive effect of rux.

Case Presentation

We report two cases of tuberculosis (TB) in primary myelofibrosis patients during rux therapy. The first patient received rux soon after diagnosis, and tracheobronchial TB (TBTB) and bronchoesophageal fistula were found after 4 months. After discontinuation of rux, antituberculosis therapy (ATT) was introduced. The second patient initiated rux due to progressive splenomegaly after 7.5 years of interferon therapy and was diagnosed with disseminated TB after 2 months. He received ATT as well. His rux was maintained due to the high burden of systematic symptoms and splenomegaly. Both myelofibrosis and TB were well controlled in these patients.

Conclusion

This is the first case report that describes rux-related TBTB accompanied by a bronchoesophageal fistula. Through a review of the literature, we provide supporting evidence to the finding that intrinsic disorders of myeloproliferative neoplasms and rux-induced immunologic deregulation together lead to TB. We highlight the importance of screening for latent TB infection and timely chemoprophylaxis before rux therapy. Once TB is diagnosed during treatment, rux is recommended to be stopped and active ATT should begin quickly.

Tuberculosis Peritonitis During Treatment of Polycythemia Vera with Ruxolitinib

Ruxolitinib is a selective JAK1/2 inhibitor that is widely used for the treatment of myeloproliferative neoplasms (MPNs), including myelofibrosis and polycythemia vera (PV). Despite its clinical efficacy for MPNs, ruxolitinib possesses immunosuppressive properties that potentially increase the risks for opportunistic infection, such as mycobacterium tuberculosis (MTB) infection, and reactivation of occult viral infection. Herein, we report the case of a 76-year-old male with PV who developed tuberculosis peritonitis under ruxolitinib therapy for 28 weeks. While previous studies and case reports have suggested an increased risk of MTB infection of various organs during ruxolitinib treatment of MPNs, this case is apparently the first of tuberculosis peritonitis in a patient with MPN treated with ruxolitinib. A review of previous case reports suggests the need for careful observation for MTB from the relatively early phase of ruxolitinib treatment, given that the median duration from the start of ruxolitinib treatment to the emergence of MTB was 20 weeks (range: 3-88 weeks). Clinicians should consider tuberculosis peritonitis as a differential diagnosis when patients with MPN treated with ruxolitinib develop infectious abdominal symptoms.

Necessity to screen and treat latent tuberculosis before ruxolitinib treatment—Ruxolitinib-associated disseminated tuberculosis: A case report and literature review

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Ruxolitinib, a JAK inhibitor, improves polycythemia vera and myelofibrosis symptoms.

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Tuberculosis (disseminated) reactivation reported after ruxolitinib treatment.

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Screening for/treating latent tuberculosis suggested before administering ruxolitinib.

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This is especially pertinent in areas where the risk of tuberculosis is high.

Ruxolitinib, a Janus kinase inhibitor, considerably improves symptoms of patients with polycythemia vera and primary or secondary myelofibrosis. However, its association with the development of infectious complications is a concern. Herein, we report the case of an 80-year-old man with primary myelofibrosis who developed disseminated tuberculosis during treatment with ruxolitinib at 15 mg twice daily and prednisone at 5 mg. We also reviewed the literature on patients who developed tuberculosis during treatment with ruxolitinib. There are 13 case reports of patients who developed tuberculosis during treatment with ruxolitinib, including our case. Disseminated tuberculosis manifestations were observed in 84.6 % of the patients and 50 % of them died. Although the interferon-gamma release assay was performed for seven of the patients with six positive results at the time of tuberculosis diagnosis, none were tested before the commencement of ruxolitinib. We suggest taking a history of tuberculosis and screening for and treating latent tuberculosis before administering ruxolitinib, especially in areas where the risk of tuberculosis is high.

A journey through infectious risk associated with ruxolitinib

Ruxolitinib has proved to be effective for the treatment of patients with myelofibrosis (either primary or secondary) and polycythaemia vera, and its approval led to a significant change in the current treatment algorithm. Despite its efficacy and beyond its well described haematological toxicity, a peculiar immunosuppressive effect emerged as our clinical experience grew, both within and outside of a clinical trial setting. Definite and negative interactions with multiple pathways of the immune system of patients have been reported so far, involving both adaptive and innate immune responses. These pathophysiological mechanisms may contribute to the increased risk of reactivation of silent infections (e.g., tuberculosis, hepatitis B virus and varicella zoster virus) that have been associated with the drug. Even though such infectious events may be fatal or may lead to significant impairment of organ function, compromising the eligibility of patients for an allotransplant procedure, there are no dedicated guidelines that may help us in assessing and managing the risk of developing serious infections. On this basis, our aim for the present work was to review the current knowledge on the pathophysiological mechanisms through which ruxolitinib may exert its immunosuppressive effect, and to illustrate our personal approach to the management of three peculiar clinical scenarios, for which a risk-based algorithm is suggested.

Mycobacterial Infections With Ruxolitinib: A Retrospective Pharmacovigilance Review

BACKGROUND

Ruxolitinib is a selective Janus kinase inhibitor (JAKI) 1/2 approved for the treatment of myelofibrosis (MF) and polycythemia vera (PV). These patients may be at risk for developing opportunistic infections. We assessed the number of patients that developed typical (Mycobacterium tuberculosis [MTB]) and atypical mycobacterial infections (AMI) while on treatment with ruxolitinib by utilizing the United States Food and Drug Administration (FDA) adverse events reporting system (FAERS).

MATERIALS AND METHODS

This is a retrospective study utilizing FAERS, a pharmacovigilance database. We queried FAERS for cases of MTB and AMI secondary to ruxolitinib between January 1, 2011 and December 31, 2018. Disproportionality signal analysis was done by calculating the reporting odds ratio (ROR). ROR was considered significant when the lower limit of 95% confidence interval (CI) was > 1.

RESULTS

There were 91 reported cases of MTB associated with ruxolitinib compared with 4575 cases from all other drugs. The ROR was significant at 9.2 (95% CI, 7.5-11.4). There were 23 reports of AMI with ruxolitinib compared with 1287 reported with all other drugs. The ROR was significant at 8.3 (95% CI, 5.5-12.6). Twelve (13.2%) patients with MTB and 8 (34.8%) with AMI died.

CONCLUSION

Patients on ruxolitinib are at increased risk of developing MTB and AMI. Clinicians should be aware of this risk and consider screening patients for latent MTB prior to initiating ruxolitinib.

Fungal Infections with Ibrutinib and Other Small-Molecule Kinase Inhibitors

Purpose of review

Small molecule kinase inhibitors (SMKIs) have revolutionized the management of malignant and autoimmune disorders. Emerging clinical reports point toward an increased risk for invasive fungal infections (IFIs) in patients treated with certain SMKIs. In this mini-review, we highlight representative examples of SMKIs that have been associated with or are expected to give rise to IFIs.

Recent findings

The clinical use of the Bruton's tyrosine kinase inhibitor ibrutinib as well as other FDA-approved SMKIs has been associated with IFIs. The fungal infection susceptibility associated with the clinical use of certain SMKIs underscores their detrimental effects on innate and adaptive antifungal immune responses.

Summary

The unprecedented development and clinical use of SMKIs is expected to give rise to an expansion of iatrogenic immunosuppressive factors predisposing to IFIs (and other opportunistic infections). Beyond increased clinical surveillance, better understanding of the pathogenesis of SMKI-associated immune dysregulation should help devising improved risk stratification and prophylaxis strategies in vulnerable patients.

Review of literature on disseminated tuberculosis with emphasis on the focused diagnostic workup

Disseminated tuberculosis (TB) is a life-threatening disease resulting from the hematogenous spread of Mycobacterium tuberculosis. The diagnosis is challenging owing to its subtle nonspecific clinical presentation, which usually reflects the underlying organ involved. Besides, tools for confirmatory laboratory diagnosis are limited. Therefore, a high index of suspicion is required for early diagnosis. Miliary pattern on chest radiography is a common finding that has an important role in the early detection of the disease. Nevertheless, approximately 10%-15% of patients have normal chest radiography. Although abnormalities are present, basic hematologic and biochemical tests as well as tuberculin skin test are nonspecific for the diagnosis. Imaging studies are helpful adjunct tools for disseminated TB as they can help determine the involved sites and guide technicians to obtain appropriate specimens for diagnosis. Clinical confirmation of the diagnosis of disseminated TB is usually based on bacteriological or histological evidence. Response to first-line anti-TB drugs is good as evidenced by many reports. This review aims to present a current update on disseminated TB with emphasis on the diagnostic workup of this devastating condition.

Primary myelofibrosis: 2019 update on diagnosis, risk-stratification and management

DISEASE OVERVIEW

Primary myelofibrosis (PMF) is a myeloproliferative neoplasm (MPN) characterized by stem cell-derived clonal myeloproliferation that is often but not always accompanied by JAK2, CALR, or MPL mutations; additional disease features include bone marrow stromal reaction including reticulin fibrosis, abnormal cytokine expression, anemia, hepatosplenomegaly, extramedullary hematopoiesis (EMH), constitutional symptoms, cachexia, leukemic progression, and shortened survival.

DIAGNOSIS

Diagnosis of PMF is based on bone marrow morphology. Presence of JAK2, CALR, or MPL mutation, expected in ∼ 90% of the patients, is supportive but not essential for diagnosis. The revised 2016 World Health Organization (WHO) classification system distinguishes "prefibrotic" from "overtly fibrotic" PMF; the former might mimic ET in its presentation and it is prognostically relevant to distinguish the two.

RISK STRATIFICATION

Two new prognostic systems for PMF have recently been introduced: GIPSS (genetically inspired prognostic scoring system) and MIPSS70+ version 2.0 (mutation- and karyotype-enhanced international prognostic scoring system). GIPSS is based exclusively on mutations and karyotype. MIPSS70+ version 2.0 utilizes both genetic and clinical risk factors. GIPSS features four and MIPSS70+ version 2.0 five risk categories. MIPSS70+ version 2.0 requires an online score calculator (http://www.mipss70score.it) while GIPPS offers a lower complexity prognostic tool.

RISK-ADAPTED THERAPY

Observation alone is advised for MIPSS70+ version 2.0 "low" and "very low" risk disease (estimated 10-year survival 56%-92%); allogeneic stem cell transplant is the preferred treatment of choice for "very high" and "high" risk disease (estimated 10-year survival 0-13%); treatment-requiring patients with intermediate-risk disease (estimated 10-year survival 30%) are best served by participating in clinical trials. All other treatment approaches, including the use of JAK2 inhibitors, are mostly palliative and should not be used in the absence of clear treatment indications. Conventional treatment for anemia includes androgens, prednisone, thalidomide and danazol, for symptomatic splenomegaly hydroxyurea and ruxolitinib and for constitutional symptoms ruxolitinib. Splenectomy is considered for drug-refractory splenomegaly and involved field radiotherapy for nonhepatosplenic EMH and extremity bone pain.