The FRACTION trial will evaluate the clinical efficacy of Fedratinib and Nivolumab combination therapy in patients with primary and secondary myelofibrosis based on the consensus criteria of the International Working Group for Myelofibrosis Research and treatment (IWG-MRT), extended by the criterion RBC-transfusion independence (RBC-TI).

The FDA recently approved fedratinib for myelofibrosis, making it just the second drug approved for the disease, as well as the second approved JAK inhibitor. The approval was based on the phase III JAKARTA trial, in which the drug significantly reduced symptoms compared with a placebo. However, the drug comes with a Boxed Warning for encephalopathy.

This is a multicenter prospective and retrospective observational clinical study with the aim of assessing the efficacy of fedratinib upon AIFA approval in patients with primary myelofibrosis or post polycythemia vera or post essential thrombocythemia myelofibrosis. Patients must meet current diagnostic criteria of MF, according to the WHO (World Health Organization) classification version 5th or the ICC (International Consensus Conference) either published in 2022 or post- polycythemia vera and post-essential thrombocythemia myelofibrosis (according to the ICC classification 2022). Patients enter the study at diagnosis or already in follow-up, at any stage of disease, except if transformed to blast phase. Patients who received fedratinib after June 2022 (time of AIFA reimbursement in Italy) will be enrolled and will be included both those ruxolitinib-naïve and ruxolitinib-exposed.

PURPOSE: Fedratinib is an orally administered Janus kinase (JAK) 2-selective inhibitor for the treatment of adult patients with intermediate-2 or high-risk primary or secondary myelofibrosis. In vitro, fedratinib is predominantly metabolized by cytochrome P450 (CYP) 3A4 and to a lesser extent by CYP2C19. Coadministration of fedratinib with CYP3A4 inhibitors is predicted to increase systemic exposure to fedratinib. This study evaluated the effect of multiple doses of the dual CYP3A4 and CYP2C19 inhibitor, fluconazole, on the pharmacokinetics of a single dose of fedratinib. METHODS: In this non-randomized, fixed-sequence, open-label study, healthy adult participants first received a single oral dose of fedratinib 100 mg on day 1. Participants then received fluconazole 400 mg on day 10 and fluconazole 200 mg once daily on days 11-23, with a single oral dose of fedratinib 100 mg on day 18. Pharmacokinetic parameters were calculated for fedratinib administered with and without fluconazole. RESULTS: A total of 16 participants completed the study and were included in the pharmacokinetic population. Coadministration of fedratinib with fluconazole increased maximum observed plasma concentration (Cmax) and area under the plasma concentration-time curve from time 0 to the last quantifiable concentration (AUC0-t) of fedratinib by 21% and 56%, respectively, compared with fedratinib alone. Single oral doses of fedratinib 100 mg administered with or without fluconazole were well tolerated. CONCLUSIONS: Systemic exposure after a single oral dose of fedratinib was increased by up to 56% when fedratinib was coadministered with fluconazole compared with fedratinib alone. TRIAL REGISTRY: CLINICALTRIALS.GOV: NCT04702464.

The purpose of the study is to evaluate the effectiveness and safety of fedratinib as maintenance therapy in participants with myeloproliferative neoplasms (MPNs) after allogeneic hematopoietic cell transplant (HCT).

This is a nonrandomized, fixed-sequence, open-label study to evaluate the effect of a single dose of fedratinib on the PK, safety, and tolerability of single doses of digoxin, rosuvastatin, and metformin in healthy subjects. The subjects will participate as follows: * Screening phase * Treatment phase (includes baseline) * Follow-up telephone call Subjects will be screened for eligibility during the screening phase. Subjects who meet all inclusion criteria and none of the exclusion criteria will return to the clinical site on Day -1 for protocol-specified assessments, and will be domiciled at the clinical site from Day -1 through the morning of Day 22. During the study, blood samples will be collected at prespecified times for PK and PD. Urine samples will be collected at prespecified times for urinary PK evaluation of metformin. Subject safety will be monitored throughout the study.

IMPORTANCE: Myelofibrosis (MF) is a BCR-ABL-negative myeloproliferative neoplasm characterized by anemia, splenomegaly, debilitating constitutional symptoms, and shortened survival. Fedratinib, a JAK2-selective inhibitor, previously demonstrated clinically beneficial activity in patients with MF in early-phase trials. OBJECTIVE: To evaluate the efficacy and safety of fedratinib therapy in patients with primary or secondary (post-polycythemia vera or post-essential thrombocythemia) MF. DESIGN, SETTING, AND PARTICIPANTS: Double-blind, randomized, placebo-controlled phase 3 study in 94 sites in 24 countries in which 289 adult patients (≥18 years of age) with intermediate-2 or high-risk primary MF, post-polycythemia vera MF, or post-essential thrombocythemia MF were randomly assigned between December 2011 and September 2012 to once-daily oral fedratinib, at a dose of 400 mg or 500 mg, or placebo, for at least 6 consecutive 4-week cycles. MAIN OUTCOMES AND MEASURES: The primary end point was spleen response (≥35% reduction in spleen volume from baseline as determined by magnetic resonance imaging or computed tomography) at week 24 and confirmed 4 weeks later. The main secondary end point was symptom response (≥50% reduction in total symptom score, assessed using the modified Myelofibrosis Symptom Assessment Form). RESULTS: The primary end point was achieved by 35 of 96 (36% [95% CI, 27%-46%]) and 39 of 97 (40% [95% CI, 30%-50%]) patients in the fedratinib 400-mg and 500-mg groups, vs 1 of 96 (1% [95% CI, 0%-3%]) in the placebo group (P < .001). Symptom response rates at week 24 were 33 of 91 (36% [95% CI, 26%-46%]), 31 of 91 (34% [95% CI, 24%-44%]), and 6 of 85 (7% [95% CI, 2%-13%]) in the fedratinib 400-mg, 500-mg, and placebo groups, respectively (P < .001). Common adverse events with fedratinib treatment were anemia, gastrointestinal symptoms, and increased levels of liver transaminases, serum creatinine, and pancreatic enzymes. Encephalopathy was reported in 4 women who received fedratinib 500 mg/d. A diagnosis of Wernicke encephalopathy was supported by magnetic resonance imaging in 3 cases and suspected clinically in 1 case. CONCLUSIONS AND RELEVANCE: Fedratinib therapy significantly reduced splenomegaly and symptom burden in patients with MF. These benefits were accompanied by toxic effects in some patients, the most important being encephalopathy of unknown mechanism. Clinical development of fedratinib was subsequently discontinued. TRIAL REGISTRATION: clinicaltrials.gov identifier: NCT01437787.

The purpose of the study is to evaluate the effectiveness, safety, and tolerability of a study drug called fedratinib in participants with myelodysplastic/myeloproliferative neoplasms (MDS/MPNs) and chronic neutrophilic leukemia (CNL).

OUTLINE: Patients receive decitabine intravenously (IV) once daily (QD) over 1 hour on days 1-10, and either ruxolitinib orally (PO) twice daily (BID), fedratinib PO daily, or pacritinib PO BID on days 1-28. Treatment repeats every 28 days for up to 6 cycles in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up for up to 5 years.

The purpose of this study is to assess the real-world safety of fedratinib for the treatment of adult participants with primary myelofibrosis (PMF), post polycythemia vera myelofibrosis (post-PV MF), or post essential thrombocythemia myelofibrosis (post-ET MF) who were previously treated with ruxolitinib. Participants will represent the overall patient population with PMF, post-PV MF or post-ET MF who lost adequate response to and/or are intolerant to ruxolitinib. Inadequate response definitions will follow Ministry of Food and Drug Safety-approved label and reimbursement criteria of the Health Insurance Review \& Assessment Service.