PAXIS Trial for VEXAS Syndrome: Study Design & Eligibility Criteria

Study Design

PAXIS Trial for VEXAS Syndrome criteria for eligibility and study design

VEXAS, Vacuoles, E1 enzyme, X-linked, Autoinflammatory, Somatic; mg, milligrams; GC, Glucocorticoid; EOW, End of Week

aPatients who are stable on GC doses of 10-14 mg daily in addition to another non-GC anti-inflammatory therapy at Screening who have a previously documented VEXAS flare on GC monotherapy at a dose of ≥10 mg may be eligible, provided their GC dose is escalated to 15-45mg daily after washout.

bTime periods for washout are variable based on type of non-GC anti-inflammatory therapy

Trial Eligibility Criteria

Key Inclusion Criteria

  • Documented evidence of a pathogenic mutation (M41 or neighboring splice site) in UBA1
  • Current or documented evidence of past inflammatory involvement within 6 months prior to enrollment
  • Receiving ongoing GC therapy at a stable prednisone or prednisolone dose of 15-45 mg/day
    • Patients who are stable on GC doses of 10-14 mg/day in addition to another non-GC anti-inflammatory therapy screening who have a previously documented VEXAS flare on a GC dose ≥10 mg/day may be eligible provided that their GC dose is escalated to 15-45 mg/day after washout
  • Karnofsky Performance Status ≥50%
  • Adequate hepatic and renal function
  • Absolute neutrophil count ≥500/µL
  • Platelet count ≥25 x 109/L
  • Peripheral blasts <5%

Key Exclusion Criteria

  • Prior allogeneic hematopoietic stem cell transplant (allo-HSCT) or solid organ transplant (other than corneal)
  • Current use of systemic GCs for conditions other than VEXAS syndrome
  • More than one prior admission to an intensive care unit due to a VEXAS Syndrome flare within the prior 6 months
  • Received ≥9 units of intensive red blood cell (RBC) transfusions in the 90 days prior to enrollment
  • Known concurrent myelodysplastic syndrome (MDS) requiring antineoplastic treatment, or allo-HSCT, or known high-risk MDS based on the Revised International Prognostic Scoring System (IPSS-R). Patients who do not meet these criteria may enroll.
  • Malignancy within 1 year prior to enrollment with the exception of MDS (per exclusion criteria), curatively treated non-melanoma skin cancer, or curatively treated carcinoma in situ. Patients with pre-malignant hematologic condition (e.g., monoclonal gammopathy of unknown significance [MGUS], clonal cytopenia of unknown significance may enroll.
  • Exposure to hypomethylating agents (HMA) within 6 months prior to enrollment, or exposure to more than 6 cycles of HMAs at any time
  • Exposure to non-GC anti-inflammatory therapy or hematologic support therapy within protocol defined timeframes prior to enrollment*
  • Exposure to anti-platelet therapy with the exception of low-dose aspirin (≤100 mg daily) within 28 days prior to enrollment
  • Grade ≥2 bleeding within the prior 3 months, unless precipitated by an inciting event
  • History of clinically significant cardiovascular disease, or clinically significant abnormalities in rhythm or conduction during Screening, including:
    • QTc > 480msec
    • Grade ≥3 cardiac event within the prior 3 months
  • New thrombosis within the prior 60 days

*Anti-CD20 agents (e.g., rituximab): 180 days, Anti-IL-23 agents (e.g., ustekinumab): 90 days, Anti-TNFα except for etanercept (e.g., infliximab): 60 days, Canakinumab: 60 days, Intravenous anti-IL-6 agents (e.g., tocilizumab): 42 days, Subcutaneous anti-IL-6 agents: 28 days, Anti-IL-17 agents (e.g., secukinumab): 28 days, Anti-integrins (e.g., vedolizumab): 60 days, Intravenous immunoglobulin: 28 days, Danazol, immunomodulatory imide drugs (ImiDs), luspatercept, or thrombopoietin receptor agonists: 28 days, Cytotoxic chemotherapy: 28 days, Etanercept: 21 days, Oral Janus kinase (JAK) inhibitors: 14 days, Anti-IL-1 agents except for canakinumab: 14 days, Any other non-GC anti-inflammatory therapy (e.g., mycophenolate, azathioprine, cyclosporine, sulfasalazine, methotrexate): 14 days

For additional information, visit:

ClinicalTrials.gov EU CTIS

*This trial is evaluating the investigational use of pacritinib in VEXAS syndrome. The safety and efficacy of pacritinib in VEXAS syndrome has not been established. Pacritinib is not approved by any Health Authority for this use.

Pacritinib (commercially known as VONJO®) was approved by U.S. Food and Drug Administration (FDA) on February 28, 2022 for the treatment of adults with myelofibrosis with a platelet count below 50 x 109/L, and has since been marketed in the US under the brand name VONJO®. This indication is approved under accelerated approval based on spleen volume reduction. Continued approval for this indication may be contingent upon verification and description of clinical benefit in a confirmatory trial(s).

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