New antibody shot shows promise for Tough-to-Treat arthritis
NCT ID NCT06590090
First seen Jun 26, 2026 · Last updated Jun 27, 2026 · Updated 1 time
Summary
This Phase 2 trial tests whether adding a lab-made antibody called natrunix to standard methotrexate treatment helps people with moderate to severe rheumatoid arthritis who haven't improved enough on methotrexate alone. About 108 participants will receive weekly shots of either natrunix or a placebo for 14 weeks, followed by an open-label extension where everyone can get natrunix. The main goal is to see if more people achieve at least a 20% improvement in arthritis symptoms.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- Natrunix (a lab-made antibody similar to a natural human antibody that blocks IL-1a), given as a shot under the skin, plus methotrexate
- What this could lead to
- If it works, this could offer a new treatment option for people with rheumatoid arthritis who do not respond well to methotrexate alone.
- What could go wrong
- This is an early Phase 2 trial with only 108 people, so results may not apply to everyone. The drug may not work better than placebo, and side effects are still being studied.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
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Phase 2
Tests whether the treatment actually works, and watches for side effects, in a larger group.
- Participants
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About 108 people
The number the study aims to enrol. It can still change while the study runs.
- Expected to start
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Jul 2026
An estimate. Start dates often move.
- Expected to finish
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Jul 2027
An estimate. End dates often move.
- Lead sponsor
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A company
The lead sponsor is a pharmaceutical, biotech, or medical-device company.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
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18 years and older
- Sex
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Anyone
- Healthy volunteers
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Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Inclusion Criteria: 1. Weight \> 40 kg 2. Diagnosis of moderate to severe RA according to 2010 ACR/EULAR classification criteria. 3. Patients must be methotrexate-inadequate responders. a. Persistent moderate to severe RA disease activity (i.e., criteria #2 above) despite ongoing treatment with MTX. 4. Meets the following minimum disease activity criteria at screening: ≥6 swollen joints (based on DAS28) and ≥6 tender joints (based on DAS28) and DAS-ESR (Erythrocyte Sedimentation Rate) \> 3.2. 5. Subject must be receiving MTX treatment at a dosage of 10-25 mg/week for a minimum of 12 weeks; and be receiving a stable dose of MTX for \>4 weeks preceding randomization. Subjects must also be in principle agreement to remain at the pre-randomization stable dose of MTX for the entire duration of the study. Subjects must also be willing to take a minimum of 5 mg folic acid/folinic acid per week for the duration of the study. 6. Subjects must have discontinued all csDMARDs (excluding MTX) for at least 4 weeks or 5 half-lives prior to enrollment, whichever is longer. 7. Subjects taking regular NSAIDs, Acetaminophen, oral corticosteroids (\<10mg/day prednisone equivalent), and inhaled corticosteroids must be on a stable dose for 2 weeks prior to enrollment. 8. Subjects must have discontinued high potency opioids (oxycodone, fentanyl, etc.) for at least 4 weeks prior to enrollment. 9. Male or female, at least 18 years of age, willing to provide informed consent, able to attend all clinic visits, comply with study-related procedures and able to understand and complete study-related questionnaires. 10. Patients must provide at least 7 consecutive days of NRS-pain data in the subject's diary prior to the baseline visit. The NRS pain diary should ideally be completed for the 7 days immediately prior to Visit 1 (when the first dose of test drug is administered). Subjects may record more than 7 days of pain records in the diary for their baseline. At least seven consecutive days of pain diary are necessary to be eligible for enrollment in the study. 11. Peripheral blood CD19+ cell count recovery to \>10 cells/uL or \>1% of total lymphocyte count (Required only for subjects who have received a Rituximab (or anti-CD20 biosimilar) infusion within 12 months prior to enrollment). 12. Female patients of childbearing potential must consent to undergo a serum pregnancy test at enrollment, and urine pregnancy tests at each visit after screening. Women of non-childbearing potential include those considered to have a medical history that indicates that pregnancy is not a reasonable risk, including post-menopausal women and those with a history of hysterectomy or surgically sterilized. 13. In case of female patients of childbearing potential, willingness to use one method of contraception of high efficacy during the entire study period. These methods can include but not limited to hormonal contraceptives, intrauterine devices, condoms, diaphragms, etc. 14. Males participating in this clinical research study should not get a sexual partner pregnant during their participation in this research study as the effect of the study drug on sperm is not known. Male contraception methods can include but are not limited to mechanical methods (e.g., abstinence, non-vaginal intercourse), contemporary methods comprising barrier methods (e.g., spermicide, condom, sponge, diaphragm and cervical cap) and vasectomy. Exclusion Criteria: 1. History of treatment with Natrunix for any reason. 2. Any active, chronic, or recurrent infections. (e.g., ongoing bacterial, viral, or fungal infection). 3. Comorbid severe psychiatric illness and/or complicated social situations that would limit compliance with study requirements. 4. Patients with a positive result of TB test (QuantiFERON-TB Gold (QFT) at screening unless the patients can present a documentation of completion of TB treatment course by the local Health Department and a clear chest x-ray at enrollment. 5. Patients who have failed more than 1 conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) regimen (excluding Methotrexate monotherapy) due to inefficacy at any point prior to enrollment. 6. Patients who have received any biological therapy including anakinra, rilonacept, canakinumab, adalimumab, certolizumab, etanercept, golimumab, infliximab, abatacept, tocilizumab, sarilumab, and biosimilars at any point prior to enrollment. 7. Treatment with JAK inhibitors at any point prior to enrollment. 8. Patients who have received treatment with Injectable corticosteroids within 8 weeks prior to enrollment. 9. Investigational therapy administered within a time interval less than at least 5 half-lives of the investigational agent prior to the first scheduled day of dosing in this study. 10. Pregnant or breastfeeding patients. 11. Patients with current drug or alcohol abuse or dependence, or a history of drug or alcohol abuse or dependence within a year prior to enrollment. 12. Uncontrolled heart disease, including NYHA Class III or IV congestive heart failure, ventricular arrhythmia, uncontrolled blood pressure (defined as ≥ 160/100 mm Hg), or unstable angina. 13. Clinically significant laboratory abnormalities, including: 1. Hemoglobin \<9.0 g/dL 2. White blood cell counts \< 4000/mm3 3. Absolute neutrophil count (ANC) \<1500/mm3 4. Platelet count \<100,000/mm3 5. Absolute lymphocyte count (ALC) \<500/mm3 6. eGFR \<45 mL/min 7. Alanine Aminotransferase (ALT) \>1.5x lab upper limit of normal (ULN) 8. Aspartate Aminotransferase (AST) \>1.5x lab upper limit of normal (ULN) 9. Bilirubin \>1.5x lab upper limit of normal (ULN) 14. Major surgery (including joint surgery) within 3 months of baseline. 15. Patients who have suffered severe trauma or fracture within 4 weeks of baseline. 16. Evidence of active hepatitis B, hepatitis C, or HIV infection. 1. Patients positive for HBsAg and/or positive for anti-HBc antibody (regardless of anti-HBs antibody status) are excluded. 2. Patients who are positive for Hepatitis C antibody and negative when the Hepatitis C RNA-PCR assay is performed on a subsequent sample will be eligible to participate. Patients who are positive for Hepatitis C antibody and have a positive result for the HCV when the Hepatitis C RNA-PCR assay is performed on the subsequent sample will not be eligible to participate. 17. Any other concomitant disease, disorder, or condition that could interfere with the interpretation of study endpoints, or the patient's ability to participate in and complete the study, including but not limited to: 1. Coexisting diseases which are contraindicated for MTX treatment. 2. Cardiovascular, renal, pulmonary, gastrointestinal, or nervous system disorders that, in the opinion of the principal investigator and/or study medical monitor, make the patient not suitable for enrollment. 3. Concurrent autoimmune disease excluding Sjogren's syndrome secondary to rheumatoid arthritis.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
How to take part
Only the study team decides who joins. These are the ways to reach them.
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The official record
ClinicalTrials.gov lists the study team's own contact details, including names and phone numbers. We don't republish those.
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A doctor treating you
A doctor who knows your case can contact a study site on your behalf, and can tell you whether this study is worth pursuing at all.
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