Antifolate Effectiveness in Arthritis

December 14, 2016 updated by: University of Alabama at Birmingham

Mechanisms of Antifolate Efficacy in Arthritis

This study looks at how the arthritis drug methotrexate works in low doses to treat rheumatoid arthritis. (High doses of methotrexate are used to treat some types of cancer.) Methotrexate blocks the action of the B-vitamin known as folic acid. We are studying the biochemical reactions affected by this vitamin because we think that blocking many of these reactions may be necessary for methotrexate to work in treating rheumatoid arthritis. Through these studies, we hope to gain a better understanding of how this drug and related drugs work as treatments for arthritis.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Low-dose methotrexate therapy suppresses autoimmune arthritis in human and animal models. We hypothesize that the effect of methotrexate in the treatment of rheumatoid arthritis is due to the inhibition of aminoimidazole-carboxamide ribotide transformylase, a folate-dependent enzyme that catalyzes the last step in the de novo biosynthesis of inosine monophosphate. The resulting accumulation of aminoimidazole carboxamide riboside inhibits adenosine deaminase, therefore interfering with normal adenosine metabolism. It is well known that children with adenosine deaminase deficiency have severe combined immunodeficiency syndrome. This suggests that adenosine deaminase activity is key to immune competence and is associated with the mechanism of efficacy in methotrexate therapy of rheumatoid arthritis.

Several studies indicate that supplemental folinic acid (5-formyltetrahydrofolate) used in large doses during low-dose methotrexate therapy for rheumatoid arthritis causes a flare in joint inflammation. However, supplemental folic acid (pteroylglutamic acid) does not lessen the efficacy of the therapy. We further hypothesize that if methotrexate efficacy is driven by aminoimidazole carboxamide ribotide transformylase inhibition, folic acid supplementation should not alter urinary levels of aminoimidazole carboxamide, adenosine, and deoxyadenosine, while folinic acid supplementation should prevent the accumulation of these compounds.

We will test our hypotheses both in people with rheumatoid arthritis and in Lewis rat adjuvant arthritis. Our objectives include: (1) determining if the dose level of methotrexate that is clinically optimal in the treatment of Lewis rat adjuvant arthritis interferes with normal adenosine metabolism; (2) determining the effectiveness of drugs that interfere with adenosine metabolism (deoxycoformycin, aminoimidazole carboxamide, and aminoimidazole carboxamide with a suboptimal dose of methotrexate) in Lewis rat adjuvant arthritis; and (3) determining whether supplemental folic acid and folinic acid during methotrexate therapy normalize adenosine metabolism in patients with rheumatoid arthritis. The information we obtain will enhance the understanding of the biochemical action of antifolates/antimetabolites that are effective in the treatment of human and animal arthritis.

Study Type

Interventional

Enrollment (Actual)

40

Phase

  • Phase 2

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Alabama
      • Birmingham, Alabama, United States, 35294
        • The University of Alabama at Birmingham

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

14 years to 81 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Individuals starting methotrexate for rheumatoid arthritis.
  • Study subjects should not currently be taking folic acid-containing vitamins.

Exclusion Criteria:

  • Cancer, renal, or liver disease.
  • Previous use of methotrexate within the past 6 months or current use of folic acid-containing supplements.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Diagnostic
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Double

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Group 1 - Folinic acid
Subjects receiving Methotrexate for 6 weeks and 5 mg of Folinic acid daily for 1 week.
Drug: Methotrexate
Dietary supplement: Folinic acid
Experimental: Group 2: Folic acid
Subjects receiving Methotrexate for 6 weeks and 5 mg of Folic acid daily for 1 week.
Drug: Methotrexate
Dietary supplement: Folic acid

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Determine the effect of Folic acid and Folinic acid on urinary 5-amino=imidazole-4-carboxaminde (AICA in individuals with rheumatoid arthritis treated with low dose methotrexate.

Secondary Outcome Measures

Outcome Measure
Determine the effect of folic acid and folinic acid on urinary adenosine excretion in individuals with rheumatoid arthritis treated with low dose methotrexate
Correlate disease activity with urinary AICA and adenosine levels

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Alabama at Birmingham

Collaborators

National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Office of Dietary Supplements (ODS)

Investigators

  • Principal Investigator: Sarah L. Morgan, M.D., R.D., University of Alabama Department of Nutrition Sciences

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

September 1, 1996

Primary Completion (Actual)

August 1, 2002

Study Completion (Actual)

August 1, 2002

Study Registration Dates

First Submitted

November 3, 1999

First Submitted That Met QC Criteria

November 3, 1999

First Posted (Estimate)

November 4, 1999

Study Record Updates

Last Update Posted (Estimate)

December 16, 2016

Last Update Submitted That Met QC Criteria

December 14, 2016

Last Verified

June 1, 2013

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • R29AR042674 (U.S. NIH Grant/Contract)
  • NIAMS-035

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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