XBiotech Advances Phase 1/2 Clinical Study of Novel True Human(TM) Therapeutic Antibody for Treating Serious Infections Due to Staphylococcus Aureus

XBiotech XBIT, the world's leading developer of next-generation True Human™ therapeutic antibodies, announced today the completion of the first cohort in its Phase 1/2 clinical study of a novel True Human monoclonal antibody therapy intended to treat all forms of Staphylococcus aureus infections, including Methicillin-resistant S. aureus (MRSA). Having met this milestone, XBiotech will advance to the next dose level in the Phase 1 portion of the study. The dose will be increased by a factor of 5, and represents the second of three planned dosing cohorts. XBiotech's antibody therapy, known as 514G3, was developed from a human donor with natural antibodies effective at neutralizing MRSA and non-MRSA forms of S. aureus. 514G3 knocks out the principle immune evasion mechanism of the bacteria, allowing white blood cells to detect and destroy the bacteria. 514G3 is expected to treat all strains of MRSA and can be used without consideration for strain-specific resistance to various antibiotics. As a True Human monoclonal antibody, 514G3 is expected to be well tolerated without the side effects or risks of antibiotics. Michael Stecher, M.D., XBiotech's Medical Director, said, "Review of the safety data from this dose cohort revealed no adverse safety signals, and we are pleased to continue enrolling and dosing patients with 514G3 in accordance with our clinical plan. Based on patient responses to date, we are eager to advance to our next dose cohort." The randomized, placebo-controlled, Phase 1/2 study is designed to evaluate dosing, safety and efficacy of 514G3 and will enroll 52 patients at approximately 16 clinical sites in the United States, Europe and Southeast Asia. Hospitalized patients with S. aureus bacteremia will be randomized to receive 514G3 plus standard of care antibiotics or placebo plus antibiotics. The study will be unblinded during the Phase 1 dose escalation stage, where the maximum tolerated dose will be determined, followed by a Phase 2 study designed to assess efficacy against S. aureus infection. Efficacy measures include time to clearance of bacteremia, as measured by blood culture, duration of fever and length of hospitalization. For more information about the study, visit www.clinicaltrials.gov.