Leflunomide. Me

Leflunomide (LEF; Arava®) is an isoxazole derivative approved by the United States FDA for the treatment of rheumatoid arthritis (RA). Currently leflunomide is the only new disease-modifying anti-rheumatic drug to be introduced in the last two decades.
Leflunomide acts slowly, it as also referred to as a “slow-acting” medication which improves rheumatoid arthritis over 3-12 months. It decreases the number of sick joints, improves pain, and leads to better overall assessments of disease activity. It is both effective and safe compared to other anti-rheumatic medications.

Leflunomide is also called a disease modifying medication, it sounds more impressive than slow-acting. The reason for introducing sych terminology is that reducing joint inflammation also results in improved function and better quality of life. In the long-term it also decreases the progression of joint damage.

LEF is an oral drug that is rapidly absorbed from the gastrointestinal tract. Leflunomide is a prodrug. This means it must be changed by patients’ own metabolisms into the active drug.
This transformation occurs in the patient’s stomach and blood soon after leflunomide is taken. Once absorbed, LEF is converted to its active form, a malononitrilamide known as teriflunomide.

The effect of leflunomide is acheieved by “turning off” the lymphocytes that attack joints. These lymphocytes are one of the major cell type causing inflammation in arthritis. In scientific terms, it the effect is acheved by the inhibition of the synthesis of a pyrimidine known as ribonucleotide uridine monophosphate pyrimidine

Leflunomide Clinical Trials

Six major clinical trials have determined that leflunomide is effective in arthritis treatment. Four of them were original research studies and the other two were follow up researches. All the trials lasted up for up to 2 years and involved 206 to 999 patients.

The conventional way to measure improvement is to assess the number of patients who improve by 20% or more on a range of measures of disease activity. Between 50% and 60% of patients improve by this amount when given leflunomide for 6 and 12 months. Without treatment less than 30% would improve in this way. These improvements are similar to those seen with other disease modifying drugs like methotrexate and sulfasalazine.

The number of patients who improve by 50% or 70% or enter remission also increases with leflunomide, though only a minority of patients will show such impressive results.