Antares Pharma, Inc. announced the positive results of a clinical study evaluating Vibex MTX, a proprietary auto injector product designed to give a rapid subcutaneous injection of methotrexate (MTX) for the treatment of rheumatoid arthritis (RA). The clinical pharmacokinetic study evaluated several dose strengths of MTX delivered by a healthcare professional to RA patients with Vibex MTX versus subcutaneous or intramuscular injection using a conventional needle and syringe. The primary end points were met with all  three methods of administration providing equivalent performance in the patients studied, together with comparable safety.

Vibex MTX is designed for rapid injection of subcutaneous MTX in three simple steps and is engineered to enable RA patients to self-inject reliably, comfortably, and conveniently at home. Safety for patients is enhanced through the use of an integrated, shielded needle and lockout system which prevents accidental needle-sticks after use. The availability of Vibex MTX could give physicians a new option to optimize both patient treatment and the use of biological agents in RA. Vibex MTX is protected by several issued and pending patents.

Paul K Wotton, president and CEO commented, “I am pleased that we have completed this clinical pharmacokinetic study with positive results and that we remain on track to file a New Drug Application (NDA) with the US Food and Drug Administration (FDA) in 2012. Patient interviews following the studies indicated that the Vibex MTX product was comfortable and easy for patients to use and preferred over a conventional needle and syringe.” Dr Wotton added, “The filing of a new patent application based on findings from the study will potentially fortify our patent portfolio around this product. Moving forward we will continue to focus our efforts on commercializing innovative injectable products designed to improve patient care and provide therapeutic benefits cost effectively.”

Used in an estimated 70 per cent of patients alone and in combination with biological therapies, MTX is a foundational Disease-Modifying Anti-Rheumatic Drug (DMARD) for RA. Generally initiated orally at lower doses and titrated up, published studies have reported as many as 30 per cent to 60 per cent of patients experience gastrointestinal side effects with oral MTX. This can prevent further dose escalation or require discontinuation in some patients which can be avoided by subcutaneous administration.

The extent of oral absorption of MTX varies considerably between patients and has been shown to decline with increasing doses. Studies have also reported that switching patients from oral to parenteral MTX improves absorption providing superior therapeutic response resulting in longer duration of use.

Independent market research commissioned by Antares with 200 rheumatologists has confirmed that physicians, if offered a reliable and patient-friendly method for self-injection, would like to switch many patients to an injectable form of MTX, potentially providing improved absorption, reduced side effects, and a better therapeutic response.

Rheumatoid Arthritis (RA) is a chronic autoimmune disorder characterized by painful inflammation of the synovial tissues lining the joints. RA generally starts between the ages of 25 and 55 years. Left untreated it often progresses to proliferation of tissues surrounding the joints and destruction of bones and cartilage, which restricts normal movement of the joint. According to the National Institutes of Health (NIH), RA affects about 1 per cent of the population worldwide, including up to 2.1 million Americans, occurring in women at twice to three times the rate as that in men.

Antares Pharma focuses on self-injection pharmaceutical products and topical gel-based medicines.