Eisai and Toyama Chemical Receive Approval to Market Anti-rheumatic Agent Iguratimod in Japan

Eisai Co., Ltd.
Toyama Chemical Co., Ltd.

Eisai Co., Ltd. (Headquarters: Tokyo, President & CEO: Haruo Naito, “Eisai”) and Toyama Chemical Co., Ltd. (Headquarters: Tokyo, President: Masuji Sugata, “Toyama Chemical”) announced today that they have received approval from Japan’s Ministry of Health, Labour and Welfare to market iguratimod (generic name; development code: T-614) for the treatment of rheumatoid arthritis.

Iguratimod, originally discovered by Toyama Chemical, is a novel disease modifying anti-rheumatic drug (DMARD) jointly developed in Japan by Eisai and Toyama Chemical based on a co-development and license agreement previously concluded between the two companies.

In a clinical study of iguratimod administered as a monotherapy in patients with rheumatoid arthritis, the agent demonstrated superiority over placebo and non-inferiority compared to an existing DMARD (salazosulfapyridine). In addition, in a trial of iguratimod in combination with methotrexate (“MTX”), the standard of care, conducted in rheumatoid arthritis patients who did not achieve satisfactory benefit with MTX alone, patients who were administered a combination of the two agents demonstrated favorable tolerability as well as significant improvements compared to those treated with placebo (MTX-only arm) in the study's primary endpoint of ACR20 response rate at Week 24. Out of all the orally-administered anti-rheumatic drugs currently approved in Japan, iguratimod is the first agent evaluated in domestic clinical trials to demonstrate efficacy as an add-on therapy to MTX in patients who did not achieve satisfactory benefit with MTX alone.

Once listed on Japan’s National Health Insurance (NHI) drug price list, iguratimod will be sold by Eisai and Taisho Toyama Pharmaceutical Co., Ltd. (Headquarters: Tokyo, President: Akira Ohira) under the brand names Careram® Tablets 25 mg and KOLBET® Tablets 25 mg, respectively, with both companies working to market the product and provide information on its proper use.
Following launch, the two companies will also conduct a special use results survey (all-case surveillance) in all patients who are administered the drug until a pre-determined number of patients has been reached.

By providing iguratimod as a new option for the pharmacological treatment of rheumatoid arthritis, Eisai and Toyama Chemical believe that they will be able to make further contributions to address the diversified needs and improve the quality of life of rheumatoid arthritis patients.

[ Please refer to the following notes for a product outline, further information on iguratimod clinical trials and a glossary of terms ]

The Iguratimod-MTX combination trial was a 52 week trial conducted in rheumatoid arthritis patients who did not achieve satisfactory benefit with MTX alone. The trial was conducted in two phases: a double-blinded phase that evaluated the efficacy and safety of iguratimod in combination with MTX compared to MTX combination with placebo; and a continuation period that evaluated the long-term safety of inguratimod-MTX in all patients. In the study’s primary end point of ACR20 (see 5 for further details) response rate at Week 24, patients treated with iguratimod demonstrated a 69.5% (114/164 patients) improvement as compared to a 30.7% (27/88 patients) improvement amongst those patients administered placebo, with the inguratimod arm showing a significant improvement in ACR20 response rate over the placebo arm (p<0.001). At Week 24, the rate of adverse drug reactions was 51.8% (85/164 patients) and 33.0% (29/88 patients) in the iguratimod and placebo arms, respectively, and 65.2% (107/ 164 patients) in the iguratimod arm at Week 52.

Rheumatoid arthritis is a disease that leads to the inflammation of multiple joints throughout the body, causing joint swelling and pain. With joint destruction progressing right from the early stages of the disease, rheumatoid arthritis causes joint deformities and functional impairment over the long term. Rheumatoid arthritis is an autoimmune disease in which synovial cells, which line the inner surface of the joint cavity, proliferate due to an unknown cause. An immune-reaction occurs in localized joints, causing an inflammatory reaction and the progression of cartilage and bone destruction due to the effects of cytokines produced by lymphocytes and macrophages. In Japan, approximately 700,000 to 800,000 patients are said to be affected by rheumatoid arthritis.

DMARDs (Disease Modifying Anti-Rheumatic Drugs) are a category of drugs that work to control the underlying processes of rheumatoid arthritis. They are expected to control the immune abnormalities that are thought to cause inflammation in the disease.

ACR20 is a criterion developed by the American College of Rheumatology that measures improvement in clinical symptoms of rheumatoid arthritis. It expresses the percentage of patients who demonstrated a 20% or greater improvement in tender and swollen joint counts and at least three of the following five disease activity variables: patient assessment of pain; patient assessment of global disease activity; physician assessment of global disease activity; patient assessment of physical function; and chronic response protein (CRP) or erythrocyte sedimentation rate (ESR) concentrations.