History

First Generation: Murine

Therapeutic antibodies for treatment of human disease were first developed from mice (murine) about twenty-years ago. Although still available as drugs, Murine antibodies have limited therapeutic value, because when injected they are recognized by the human body as foreign substances. The ensuing human immune response neutralizes the foreign antibody, thus limiting its effectiveness and even resulting in dangerous side effects, such as anaphylaxis.

Second Generation: Chimeric

Soon after the arrival of murine antibodies for treating human disease, therapeutic antibodies were introduced that were fusion molecules, combining murine and human antibody segments. These so called chimeric antibodies have achieved great commercial success, and include the blockbuster product Rituxan™, used to treat certain kinds of cancer.

Third Generation: Humanized

While chimeric antibodies were finding their way into human therapies, other sophisticated approaches to further reduce murine content of antibodies were well underway. In addition to the fusion of murine and human segments that comprised the chimeric antibodies, humanized antibodies further interspersed human sequences into the murine segments. From 2003-2006, sales growth for therapeutic antibodies was primarily driven by the humanized products, although chimeric antibodies continued to hold strong market positions.

Fourth Generation: “Fully Human”

More recently, research and development efforts in the industry have centered on the production of so called “fully human” antibodies. Despite the reassuring title, these antibodies are actually not from a human but are engineered, or produced in mice that have been genetically modified to incorporate human antibody gene sequences. Extensive clinical experience with these antibodies now suggest that fully human antibodies still may be recognized by the human immune system as foreign substances.

Next Generation: True Human™

XBiotech is pioneering the development of true human therapeutic antibodies. That is, our antibodies are derived from a naturally occurring human antibody, cloned from a human gene involved in a human immune response. The Company believes that True Human™ antibodies should not be detected by the human immune system as a foreign substance, and depending on target, are expected to exhibit excellent safety, efficacy and commercial value compared to earlier generation antibody therapeutics.