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

Cavitary lung lesions caused by Pneumocystis jirovecii in a patient with myelofibrosis on ruxolitinib

We report a rare case of a patient with Janus kinase 2-positive myelofibrosis on ruxolitinib, presenting with indolent pneumonia and cavitary lung lesions. Initial transthoracic biopsy was non-specific, but thoracoscopic biopsy revealed necrotising granulomatous disease caused by Pneumocystis jirovecii pneumonia (PJP). The patient, initially treated with trimethoprim-sulfamethoxazole, was switched to atovaquone due to gastrointestinal intolerance. Given the patient's immunosuppression and extensive cavitary lesions, an extended course of atovaquone was administered, guided by serial imaging, resulting in clinical and radiological improvement. Unfortunately, the patient later passed away from a severe SARS-CoV-2 infection before complete radiographic resolution was observed. This case highlights the importance of recognising atypical PJP presentations causing granulomatous disease in immunosuppressed patients. While rare, documenting such cases may improve diagnosis using less invasive methods and help determine optimal treatment durations for resolution of these atypical infections.

Ruxolitinib associated psoas muscle tuberculosis abscess in a primary myelofibrosis woman: A case report and literature review

RATIONALE

Primary myelofibrosis is a subtype of myeloproliferative neoplasm that leads to bone marrow fibrosis. Historically, the only curative option for primary myelofibrosis was allogeneic hematopoietic stem cell transplant. Ruxolitinib, a Janus kinase inhibitor, is now used for the treatment of primary myelofibrosis and polycythemia vera. It effectively improves symptoms related to splenomegaly and anemia. However, its association with the development of opportunistic infections has been observed in clinical studies and practical application.

PATIENT CONCERNS

A 64-year-old female with primary myelofibrosis and chronic hepatitis B infection who received ruxolitinib treatment. She was admitted for spiking fever and altered consciousness.

DIAGNOSIS

Tuberculosis meningitis was suspected but cerebrospinal fluid can't identify any pathogens. An abdominal computed tomography scan revealed a left psoas abscess and an enlarged spleen. A computed tomography-guided pus drainage procedure was performed, showing a strong positive acid-fast stain and a positive Mycobacterium tuberculosis polymerase chain reaction result.

INTERVENTIONS

antituberculosis medications were administered. The patient developed a psoas muscle abscess caused by tuberculosis and multiple dermatomes of herpes zoster during antituberculosis treatment.

OUTCOMES

The patient was ultimately discharged after 6 weeks of treatment without apparent neurological sequelae.

LESSONS

This case underscores the importance of clinicians evaluating latent infections and ensuring full vaccination prior to initiating ruxolitinib-related treatment for primary myelofibrosis.

Ocular side effects of oncological therapies: Review

With the advance of cancer therapy in recent years, the knowledge of the mechanisms involved in this disease has increased, which has meant an increase in the quality of life and survival of patients with tumor pathologies previously considered incurable or refractory to treatment. The number of drugs used has increased exponentially in number, and although the implicit toxicity is lower than that of conventional antineoplastic therapy, they lead to the appearance of new associated adverse effects that the ophthalmologist must recognize and manage.

Serious infections in patients with VEXAS syndrome: data from the French VEXAS registry

INTRODUCTION

Vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic (VEXAS) syndrome is an acquired autoinflammatory monogenic disease with a poor prognosis whose determinants are not well understood. We aimed to describe serious infectious complications and their potential risk factors.

METHODS

Retrospective multicentre study including patients with VEXAS syndrome from the French VEXAS Registry. Episodes of serious infections were described, and their risk factors were analysed using multivariable Cox proportional hazards models.

RESULTS

Seventy-four patients with 133 serious infections were included. The most common sites of infection were lung (59%), skin (10%) and urinary tract (9%). Microbiological confirmation was obtained in 76%: 52% bacterial, 30% viral, 15% fungal and 3% mycobacterial. Among the pulmonary infections, the main pathogens were SARS-CoV-2 (28%), Legionella pneumophila (21%) and Pneumocystis jirovecii (19%). Sixteen per cent of severe infections occurred without any immunosuppressive treatment and with a daily glucocorticoid dose ≤10 mg. In multivariate analysis, age >75 years (HR (95% CI) 1.81 (1.02 to 3.24)), p.Met41Val mutation (2.29 (1.10 to 5.10)) and arthralgia (2.14 (1.18 to 3.52)) were associated with the risk of serious infections. JAK inhibitors were most associated with serious infections (3.84 (1.89 to 7.81)) compared with biologics and azacitidine. After a median follow-up of 4.4 (2.5-7.7) years, 27 (36%) patients died, including 15 (56%) due to serious infections.

CONCLUSION

VEXAS syndrome is associated with a high incidence of serious infections, especially in older patients carrying the p.Met41Val mutation and treated with JAK inhibitors. The high frequency of atypical infections, especially in patients without treatment, may indicate an intrinsic immunodeficiency.

Management of polycythemia vera: A survey of treatment patterns in Italy

OBJECTIVES

Polycythemia vera (PV) is an acquired clonal hematopoietic stem cell disorder characterized by the overproduction of red blood cells. It has long been underlined that there are differences in treatment patterns in routine practice. Therapeutic strategies have also expanded, and in recent years the JAK1/JAK2 inhibitor ruxolitinib has emerged as a second-line therapeutic option in patients who are intolerant to or resistant to hydroxyurea. Determining the impact of changes on practice patterns is of interest, especially for aspects that lack detailed guidance for management.

METHODS

To gain insights into treatment patterns by clinicians treating patients with PV in Italy, we carried out a survey of 60 hematologists and transfusion specialists. The questions covered: treatment of low-risk patients, definition of significant leukocytosis, splenomegaly and excessive phlebotomies, resistance/intolerance to hydroxyurea, use of ruxolitinib, cytoreductive therapy, and vaccines.

RESULTS

In general, the results of the survey indicate that there is a large heterogeneity in management of patients with PV across these areas.

CONCLUSIONS

While helping to provide greater understanding of treatment patterns for patients with PV in Italy, our survey highlights the need for additional clinical studies to obtain more precise guidance for the routine care of patients with PV.

SOHO State of the Art Updates and Next Questions | Polycythemia Vera: Is It Time to Rethink Treatment?

Polycythemia vera (PV) is a Philadelphia-negative myeloproliferative neoplasm characterized by excessive myeloid cells production, mostly secondary to mutations in the Janus kinase 2 (JAK2) gene. PV natural history might be burdened by thrombotic events (TEs) and evolution into post-PV myelofibrosis (PPV-MF) or blast phase (BP). To date, no treatment strategies have been shown to have disease modifying effects, so therapy is directed at preventing TEs. All patients require phlebotomies (PHLs) to keep hematocrit below 45% and once-daily low dose aspirin (if not contraindicated). Apart from patients at "high risk" because of age over 60 years or a thrombosis history, cytoreductive therapies (CT) should be given to patients with relevant signs of myeloproliferation or intolerance to PHLs. Approved choices both for first and second line CT are hydroxyurea (HU) and pegylated forms of interferon (peg-IFN), the latter probably being better for young patients, and subjects without critical and recent vascular events or massive splenomegaly. The JAK1/2 inhibitor ruxolitinib is the treatment of choice in case of resistance/intolerance to HU, with proved efficacy in terms of thrombotic prevention. Data are too preliminary to consider CT for "low risk" PV cases, but ropeg-IFN is being studied in this setting with a short follow-up. A careful monitoring for signs of evolution into PPV-MF is fundamental for optimizing patient management.

Impaired Antibody Response Following the Second Dose of the BNT162b2 Vaccine in Patients With Myeloproliferative Neoplasms Receiving Ruxolitinib

Data on the effect of ruxolitinib on antibody response to severe acute respiratory coronavirus 2 (SARS-CoV-2) vaccination in patients with myeloproliferative neoplasms (MPN) is lacking. We prospectively evaluated anti-spike-receptor binding domain antibody (anti-S Ab) levels after the second dose of the BNT162b2 (Pfizer-BioNTech) vaccine in MPN patients. A total of 74 patients with MPN and 81 healthy controls who were vaccinated were enrolled in the study. Of the MPN patients, 27% received ruxolitinib at the time of vaccination. Notably, MPN patients receiving ruxolitinib had a 30-fold lower median anti-S Ab level than those not receiving ruxolitinib (p < 0.001). Further, the anti-S Ab levels in MPN patients not receiving ruxolitinib were significantly lower than those in healthy controls (p < 0.001). Regarding a clinical protective titre that has been shown to correlate with preventing symptomatic infection, only 10% of the MPN patients receiving ruxolitinib had the protective value. Univariate analysis revealed that ruxolitinib, myelofibrosis, and longer time from diagnosis to vaccination had a significantly negative impact on achieving the protective value (p = 0.001, 0.021, and 0.019, respectively). In subgroup analysis, lower numbers of CD3⁺ and CD4⁺ lymphocytes were significantly correlated with a lower probability of obtaining the protective value (p = 0.011 and 0.001, respectively). In conclusion, our results highlight ruxolitinib-induced impaired vaccine response and the necessity of booster immunisation in MPN patients. Moreover, T-cell mediated immunity may have an important role in the SARS-CoV-2 vaccine response in patients with MPN, though further studies are warranted.

Safety and effectiveness of ruxolitinib in the real-world management of polycythemia vera patients: a collaborative retrospective study by pH-negative MPN latial group

Ruxolitinib is approved for polycythemia vera (PV) patients after failure to previous cytoreductive therapy, based on durable results observed in phase 3 trials. We report a multicenter retrospective study demonstrating the efficacy and safety of ruxolitinib in real-life setting. Eighty-three patients were evaluated. Median follow-up was 24.5 months (IQR 14.0-29.3). At a 3-month response assessment, ruxolitinib provided significant benefit in reducing hematocrit (HCT) level (p < 0.001), phlebotomy requirement (p < 0.001), leucocytes (p = 0.044), and disease-related symptoms (p < 0.001). The exposure-adjusted rates (per 100 patient-years) of infectious complications, thromboembolic events, and secondary malignancies were 6.9, 3, and 3.7, respectively. Non-melanoma skin cancers (NMSC) were the most frequent (40%) SM type. Lymphoproliferative disorders were not detected. Five (6%) patients permanently discontinued ruxolitinib treatment and four (5%) evolved in myelofibrosis (MF), but none in acute leukemia. The rate of MF evolution per 100 patient-years of exposure was 2.8. In our experience, ruxolitinib confirmed its efficacy and safety outside of clinical trials.

Early Use of Low-Dose Ruxolitinib: A Promising Strategy for the Treatment of Acute and Chronic GVHD

Janus kinases (JAK) are a family of tyrosine kinases (JAK1, JAK2, JAK3, and TYK2) that transduce cytokine-mediated signals through the JAK–STAT metabolic pathway. These kinases act by regulating the transcription of specific genes capable of inducing biological responses in several immune cell subsets. Inhibition of Janus kinases interferes with the JAK–STAT signaling pathway. Besides being used in the treatment of cancer and inflammatory diseases, in recent years, they have also been used to treat inflammatory conditions, such as graft-versus-host disease (GVHD) and cytokine release syndrome as complications of allogeneic hematopoietic stem cell transplantation and cell therapy. Recently, the FDA approved the use of ruxolitinib, a JAK1/2 inhibitor, in the treatment of acute steroid-refractory GVHD (SR-aGVHD), highlighting the role of JAK inhibition in this immune deregulation. Ruxolitinib was initially used to treat myelofibrosis and true polycythemia in a high-dose treatment and caused hematological toxicity. Since a lower dosage often could not be effective, the use of ruxolitinib was suspended. Subsequently, ruxolitinib was evaluated in adult patients with SR-aGVHD and was found to achieve a rapid and effective response. In addition, its early low-dose use in pediatric patients affected by GVHD has proved effective, safe, and reasonably preventive. The review aims to describe the potential properties of ruxolitinib to identify new therapeutic strategies.

JAK2 in Myeloproliferative Neoplasms: Still a Protagonist

The discovery of the activating V617F mutation in Janus kinase 2 (JAK2) has been decisive for the understanding of myeloproliferative neoplasms (MPN). Activated JAK2 signaling by JAK2, CALR, and MPL mutations has become a focus for the development of targeted therapies for patients with MPN. JAK2 inhibitors now represent a standard of clinical care for certain forms of MPN and offer important benefits for MPN patients. However, several key aspects remain unsolved regarding the targeted therapy of MPN with JAK2 inhibitors, such as reducing the MPN clone and how to avoid or overcome a loss of response. Here, we summarize the current knowledge on the structure and signaling of JAK2 as central elements of MPN pathogenesis and feature benefits and limitations of therapeutic JAK2 targeting in MPN.

T Helper Cell Lineage-Defining Transcription Factors: Potent Targets for Specific GVHD Therapy?

Allogenic hematopoietic stem cell transplantation (allo-HSCT) represents a potent and potentially curative treatment for many hematopoietic malignancies and hematologic disorders in adults and children. The donor-derived immunity, elicited by the stem cell transplant, can prevent disease relapse but is also responsible for the induction of graft-versus-host disease (GVHD). The pathophysiology of acute GVHD is not completely understood yet. In general, acute GVHD is driven by the inflammatory and cytotoxic effect of alloreactive donor T cells. Since several experimental approaches indicate that CD4 T cells play an important role in initiation and progression of acute GVHD, the contribution of the different CD4 T helper (Th) cell subtypes in the pathomechanism and regulation of the disease is a central point of current research. Th lineages derive from naïve CD4 T cell progenitors and lineage commitment is initiated by the surrounding cytokine milieu and subsequent changes in the transcription factor (TF) profile. Each T cell subtype has its own effector characteristics, immunologic function, and lineage specific cytokine profile, leading to the association with different immune responses and diseases. Acute GVHD is thought to be mainly driven by the Th1/Th17 axis, whereas Treg cells are attributed to attenuate GVHD effects. As the differentiation of each Th subset highly depends on the specific composition of activating and repressing TFs, these present a potent target to alter the Th cell landscape towards a GVHD-ameliorating direction, e.g. by inhibiting Th1 and Th17 differentiation. The finding, that targeting of Th1 and Th17 differentiation appears more effective for GVHD-prevention than a strategy to inhibit Th1 and Th17 cytokines supports this concept. In this review, we shed light on the current advances of potent TF inhibitors to alter Th cell differentiation and consecutively attenuate GVHD. We will focus especially on preclinical studies and outcomes of TF inhibition in murine GVHD models. Finally, we will point out the possible impact of a Th cell subset-specific immune modulation in context of GVHD.

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.

Disseminated blastomycosis in a patient with polycythemia vera on ruxolitinib

Ruxolitinib (RUX) is a kinase inhibitor used in the treatment of various medical conditions and its mechanism of action involves suppression of the immune system. While beneficial in treatment of polycythemia vera, myelofibrosis and other indications, it can also increase a patient's susceptibility to various infections, including bacterial, viral and fungal. We present a case of a patient being treated with RUX who presented with a disseminated fungal infection. This case emphasises the need for vigilance of endemic fungal infections in individuals who are on RUX therapy.

Data-driven analysis of the kinetics of the JAK2V617F allele burden and blood cell counts during hydroxyurea treatment of patients with polycythemia vera, essential thrombocythemia, and primary myelofibrosis

BACKGROUND

Hydroxyurea (HU) treatment of patients with essential thrombocythemia (ET), polycythemia vera (PV), and primary myelofibrosis (PMF) (MPNs) normalizes elevated blood cell counts within weeks in the large majority of patients. Studies on the impact of HU upon the kinetics of the JAK2V617F allele burden, leukocyte, and platelet counts over time are scarce.

PURPOSE

Using data-driven analysis as a novel tool to model the kinetics of the JAK2V617F allele burden and blood cell counts over time during treatment with HU.

MATERIAL AND METHODS

Using serial measurements of JAK2V617F and correlation analysis of routine hematological values (the Hb-concentration, leukocyte count, platelet count, and lactic dehydrogenase), we present a detailed description and analysis of the kinetics of the JAK2V617F, leukocyte, and platelet counts and lactic dehydrogenase in 27 patients (PV = 18; ET = 7; PMF = 2), who were followed in the Danish randomized trial (DALIAH). To further analyze the JAK2V617F kinetics, we use a machine learning clustering algorithm to group the response patterns.

RESULTS

Response patterns were highly heterogeneous, with clustering resulting in 3 groups and 3 outliers. In the large majority of patients, HU treatment was initially associated with a modest decline in the JAK2V617F allele burden in concert with a decline in leukocyte and platelet counts. However, HU did not induce a sustained and continuous decrease in the JAK2V617F allele burden.

CONCLUSION

Using data-driven analysis of the JAK2V617F allele burden, leukocyte, and platelet kinetics during treatment with HU, we have shown that HU does not induce a sustained decrease in the JAK2V617F allele burden and neither induces sustained normalization of elevated cell counts in MPN patients. Our results may explain why MPN patients during treatment with HU still have a substantially increased risk of thrombosis.

Cryptococcal fungemia and Mycobacterium haemophilum cellulitis in a patient receiving ruxolitinib: a case report and literature review

Background

Ruxolitinib is a novel oral Janus kinase inhibitor that is used for treatment of myeloproliferative diseases. It exhibits potent anti-inflammatory and immunosuppressive effects, and may increase the risk of opportunistic infections. Here, we report a rare case of Cryptococcus neoformans and Mycobacterium haemophilum coinfection in a myelofibrosis patient who was receiving ruxolitinib.

Case presentation

A 70-year-old Thai man who was diagnosed with JAK2V617F-mutation-positive primary myelofibrosis had been treated with ruxolitinib for 4 years. He presented with cellulitis at his left leg for 1 week. Physical examination revealed fever, dyspnea, desaturation, and sign of inflammation on the left leg and ulcers on the right foot. Blood cultures showed positive for C. neoformans. He was prescribed intravenous amphotericin B deoxycholate with a subsequent switch to liposomal amphotericin B due to the development of acute kidney injury. He developed new onset of fever after 1 month of antifungal treatment, and the lesion on his left leg had worsened. Biopsy of that skin lesion was sent for mycobacterial culture, and the result showed M. haemophilum. He was treated with levofloxacin, ethambutol, and rifampicin; however, the patient eventually developed septic shock and expired.

Conclusions

This is the first case of C. neoformans and M. haemophilum coinfection in a patient receiving ruxolitinib treatment. Although uncommon, clinicians should be aware of the potential for multiple opportunistic infections that may be caused by atypical pathogens in patients receiving ruxolitinib.