Rheumatoid Arthritis (RA)Phase 4NCT06913907
Changes in MTX-PG Concentrations During Subcutaneous MTX Therapy in Patients With Rheumatoid Arthritis(COSMOS Study)
A Phase 4 study testing Methotrexate (MTX) in people with Rheumatoid Arthritis (RA), run by Keio University at 1 site in Japan.
Trial summary
Methotrexate is known to exist intracellularly as methotrexate polyglutamate, which is formed by the addition of glutamic acid after absorption into the body. The objective of this study is to measure the concentration of methotrexate polyglutamate in red blood cells and peripheral blood mononuclear cells after… Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Rheumatoid Arthritis (RA)
- What is being tested?
- Methotrexate (MTX)
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 100 participants
- Where
- 1 siteJapan
- Study dates
- 10 Apr 2025to 31 Dec 2027
- Phase
- Phase 4
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 1) Patients who were previously untreated with MTX, regardless of route of administration 2) Patients aged >=18 years at the time of informed consent 3) Patients who meet 2010 EULAR/ACR criteria 4) Patients who have disease activity of SDAI >11 at screening 5) Patients who were previously untreated with JAK inhibitor or bDMARDs 6) Female of child-bearing potential who can use appropriate contraceptive during the study and for at least one menstrual period after completion of MTX administration, female in whom time from menopause to informed consent is >=1 year, or female of no child-bearing potential through sterilization 7) Virile male who can use appropriate contraceptive during the study and for at least three months after completion of MTX administration 8) Patients who can adequately understand this study procedures, and voluntarily consent in writing to take part in this study
Who cannot join
- 1) Pregnant women or women who may be pregnant 2) Patients with a history of hypersensitivity to any ingredient of the study drug 3) Patients with serious hematologic and lymphatic disorders
- Patients with a history of myelodysplastic syndrome, aplastic anemia, or erythroblastoma
- Patients with a diagnosis or treatment of lymphoproliferative disease within the past 5 years
- Patients with significant leukopenia (white blood cell count <3000/mm3) or thrombocytopenia (platelet count <50000/mm3millimeter) 4) Patients with significant hepatic impairment
- Patients with acute or chronic active viral hepatitis B or C
- Patients diagnosed with cirrhosis
- Patients with other significant hepatic impairment (AST >150 U/L or ALT >150 U/L) 5) Patients with severe renal impairment The following criteria should be used as a reference.
- Dialysis patients or renal dysfunction correspon ding to renal glomerular filtration rate (GFR) <30 mL/min/1.73 m2 6) Patients who have pleural effusion or ascites 7) Patients who have active tuberculosis 8) Patients otherwise whom principal investigator/sub- investigator considered medically ineligible to participate in the study
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Japan1 site, 1 recruiting
- Recruiting
Keio University Hospital
Shinjuku-ku, Tokyo, 35 Shinanomachi
Yuko Kaneko, +81-3-5363-3786, ykaneko.z6@keio.jp
About this study
Official title: Changes in Methotrexate Polyglutamate Concentrations When Changing From Oral to Subcutaneous Methotrexate Therapy in Methotrexate-naive Patients With Rheumatoid Arthritis: (COSMOS Study)
Methotrexate is known to exist intracellularly as methotrexate polyglutamate, which is formed by the addition of glutamic acid after absorption into the body.
The objective of this study is to measure the concentration of methotrexate polyglutamate in red blood cells and peripheral blood mononuclear cells after initiating methotrexate treatment in patients with rheumatoid arthritis who have no prior history of using methotrexate (either subcutaneous or oral formulations). Additionally, we aim to examine changes in methotrexate polyglutamate concentrations when switching from oral methotrexate to subcutaneous Metoject, as well as to investigate the relationship between methotrexate polyglutamate concentration and the efficacy and safety of the treatment. Another objective of this study is to evaluate whether switching to subcutaneous Metoject allows for an increased maximum tolerable dosage while maintaining safety.
- Conditions
- Rheumatoid Arthritis (RA)
- Being tested
- Methotrexate (MTX)
- Medical subject headings
- Arthritis, Rheumatoid
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Methotrexate (MTX)Drug
Single arm study
| Study group | Role | What they receive |
|---|---|---|
| MTX group | Other | Not described Receives: Drug: Methotrexate (MTX) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in MTX-PG concentrations in erythrocytes from baseline
Measured: From enrollment to the end of treatment at 24 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 Apr 2025
- Study start10 Apr 2025 (estimated)
- Primary completion31 Dec 2027 (estimated)
- Study completion31 Dec 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Rheumatoid Arthritis (RA)Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Keio University
- Sponsor type
- University, hospital or other
- Collaborators
- Eisai Co., Ltd., Mebix Inc
- Responsible party
- Principal investigator, Yuko Kaneko, Keio University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06913907
- Sponsor's protocol ID
- N20240003
- Status last verified
- Mar 2025
- First submitted
- 30 Mar 2025
- Last updated
- 6 Apr 2025
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 6 Apr 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Changes in Methotrexate Polyglutamate Concentrations When Changing From Oral to Subcutaneous Methotrexate Therapy in Methotrexate-naive Patients With Rheumatoid Arthritis: (COSMOS Study)
- ClinicalTrials.gov ID
- NCT06913907
- Acronym / sponsor ID
- N20240003
- Conditions
- Rheumatoid Arthritis (RA)
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- Keio UniversityUniversity, hospital or other
- Collaborators
- Eisai Co., Ltd., Mebix Inc
- Study start
- 10 Apr 2025 (estimated)
- Primary completion
- 31 Dec 2027 (estimated)
- Study completion
- 31 Dec 2027 (estimated)
- First posted
- 6 Apr 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Methotrexate is known to exist intracellularly as methotrexate polyglutamate, which is formed by the addition of glutamic acid after absorption into the body.
The objective of this study is to measure the concentration of methotrexate polyglutamate in red blood cells and peripheral blood mononuclear cells after initiating methotrexate treatment in patients with rheumatoid arthritis who have no prior history of using methotrexate (either subcutaneous or oral formulations). Additionally, we aim to examine changes in methotrexate polyglutamate concentrations when switching from oral methotrexate to subcutaneous Metoject, as well as to investigate the relationship between methotrexate polyglutamate concentration and the efficacy and safety of the treatment. Another objective of this study is to evaluate whether switching to subcutaneous Metoject allows for an increased maximum tolerable dosage while maintaining safety.
Study design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| MTX group | Other | Drug: Methotrexate (MTX) |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- 1) Patients who were previously untreated with MTX, regardless of route of administration 2) Patients aged >=18 years at the time of informed consent 3) Patients who meet 2010 EULAR/ACR criteria 4) Patients who have disease activity of SDAI >11 at screening 5) Patients who were previously untreated with JAK inhibitor or bDMARDs 6) Female of child-bearing potential who can use appropriate contraceptive during the study and for at least one menstrual period after completion of MTX administration, female in whom time from menopause to informed consent is >=1 year, or female of no child-bearing potential through sterilization 7) Virile male who can use appropriate contraceptive during the study and for at least three months after completion of MTX administration 8) Patients who can adequately understand this study procedures, and voluntarily consent in writing to take part in this study
Key exclusion criteria (8 listed)
- 1) Pregnant women or women who may be pregnant 2) Patients with a history of hypersensitivity to any ingredient of the study drug 3) Patients with serious hematologic and lymphatic disorders
- Patients with a history of myelodysplastic syndrome, aplastic anemia, or erythroblastoma
- Patients with a diagnosis or treatment of lymphoproliferative disease within the past 5 years
- Patients with significant leukopenia (white blood cell count <3000/mm3) or thrombocytopenia (platelet count <50000/mm3millimeter) 4) Patients with significant hepatic impairment
- Patients with acute or chronic active viral hepatitis B or C
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Methotrexate (MTX)Single arm study | Drug | MTX group |
Primary outcome
Change in MTX-PG concentrations in erythrocytes from baseline
Time frame: From enrollment to the end of treatment at 24 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Apr 2025.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Methotrexate (MTX) in people with Rheumatoid Arthritis (RA), run by Keio University at 1 site in Japan.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 6 Apr 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Japan. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Kaneko Yuko (+81-3-5363-3786, ykaneko.z6@keio.jp), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in MTX-PG concentrations in erythrocytes from baseline (time frame: From enrollment to the end of treatment at 24 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 Apr 2025; AzTrials last refreshed its copy on 26 Oct 2026.