Antares Pharma, Inc. (NASDAQ: ATRS) today announced positive results from a human factors usability study for VIBEX Methotrexate (MTX), a proprietary auto injector product designed to self-administer a rapid subcutaneous weekly injection of methotrexate for the treatment of rheumatoid arthritis (RA). The purpose of this study was to conduct a cumulative and summative round of simulated usability testing of the VIBEX MTX device in accordance with Food and Drug Administration (FDA) draft guidance “Applying Human Factors and Usability Engineering to Optimize Medical Device Design, dated June 22, 2011”. The study design was reviewed by the FDA prior to initiation. Fifty individuals representing three user groups participated in this study, including 17 RA patients, 16 lay caregivers and 17 healthcare professionals. All participants in the patient group had been diagnosed with rheumatoid arthritis by a physician. In addition, the patients were screened twice using the Health Assessment 20 Item Disability Scale (HAQ) to determine the extent of hand function impairment of the sort associated with RA patients. Patients with an average HAQ score of 2.0 to 2.5, defined as “severe to very severe” hand function impairment, were enrolled into the study. The RA patients and lay caregivers (n=33) completed simulated injections on two days spaced one week apart, which is reflective of the intended weekly dosing. The healthcare professionals (n=17) participated in a single session where they used the device on a simulated patient. The results of the study showed that the VIBEX MTX device is safe and effective for intended users, uses and use environments. The validation testing proved the product is easy to learn and safe to use as demonstrated by correct and successful injections. The Company is continuing to conduct additional studies including an ongoing human use study in 100 RA patients, and expects to complete enrolment in this study during the third quarter of 2012. Antares Pharma continues to expect and remains on track for a first quarter 2013 NDA filing of VIBEX MTX for self-injection by patients with rheumatoid arthritis.