NCT06590090

Natrunix in Combination With Methotrexate for Rheumatoid Arthritis Treatment

Phase II, Double-Blind, Placebo-Controlled, Randomized Trial Examining Natrunix in Combination With Methotrexate for the Treatment of Rheumatoid Arthritis

• Status: Not Yet Recruiting
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 108 (estimated)
• Sponsor: XBiotech, Inc. · Industry
• Sex: All
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

Approximately 108 subjects will be randomized in 2 arms in 2:1 ratio to receive weekly subcutaneous injections of either 400mg Natrunix + MTX weekly or placebo + MTX weekly for 14 weeks. At the week 14 visit subjects in both arms will undergo a safety follow up visit OR begin receiving biweekly subcutaneous injections of 400mg Natrunix for 14 weeks as part of an Open Label Extension (OLE). The study will last for a maximum of 33 weeks, including: a screening period of up to 4 weeks, a 14-week double-blinded treatment phase followed by a 14-week open label extension phase and one-week follow-up.

Detailed description

Number of Planned Subjects: Approximately 108 subjects within 2 arms randomized 2:1 \[400 mg Natrunix + MTX weekly (n=72) or placebo + MTX weekly arms (n=36)\]. Study Duration: The study will last for a maximum of 33 weeks, including: a screening period of up to 4 weeks, a 14-week double-blinded treatment phase followed by a 14-week open label extension phase and one-week follow-up. Study Design: Subjects will be randomized into the study in a 2:1 ratio to receive weekly subcutaneous injections of either 400mg Natrunix + MTX weekly or placebo + MTX weekly for 14 weeks. At the week 14 visit subjects in both arms will undergo a safety follow up visit OR begin receiving biweekly subcutaneous injections of 400mg Natrunix for 14 weeks as part of an Open Label Extension (OLE). Subjects will undergo a preliminary assessment for study eligibility. Subjects who meet pre-screening requirements may then provide informed consent to acknowledge understanding of and accept enrollment into the clinical study. Subjects enrolled in the study will be taking concomitant methotrexate, have a diagnosis of moderate to severe RA according to 2010 ACR/EULAR classification criteria and have ≥6 swollen joints (based on DAS28), ≥6 tender joints (based on DAS28) and DAS-ESR \> 3.2.

Conditions

• Rheumatoid Arthritis

Interventions

Type	Name	Description
BIOLOGICAL	Natrunix 400 mg	The active ingredient of Natrunix is an IgG4 monoclonal antibody indistinguishable from that naturally occurring in an IL-1a-immune healthy human. Natrunix is formulated as 200 mg/mL sterile liquid in a stabilizing isotonic formulation buffered to pH 7.0. The product is filled into a 2 mL glass pre-filled syringe suitable for subcutaneous injection. The drug product is formulated and buffered to a neutral body pH of 7.0.
DRUG	Placebo	Placebo is a sterile liquid solution filled into a 2 mL glass pre-filled syringe, suitable for subcutaneous injection, containing the exact same buffer matrix used for Natrunix drug product
DRUG	Methotrexate (MTX)	Methotrexate may be administered in pill form by mouth, as liquid by mouth, or by subcutaneous injection.Subjects enrolled in this study should be receiving a stable minimum weekly dose of 10mg. Weekly methotrexate should not exceed 25 mg/week.

Timeline

• Start date: 2026-07-15
• Primary completion: 2027-01-15
• Completion: 2027-07-15
• First posted: 2024-09-19
• Last updated: 2025-12-09

Regulatory

• FDA-regulated drug study