PINE BROOK, NJ, USA I February 12, 2015 I Elusys Therapeutics, Inc. (Elusys), a biopharmaceutical company developing antibody therapies to treat infectious disease, presented data demonstrating that obiltoxaximab (ETI-204) demonstrated a statistically significant survival benefit across a range of disease severity in animal model studies assessing treatment of inhalational anthrax, as well as effectiveness in post-exposure prophylaxis. Obiltoxaximab is the company’s investigational monoclonal antibody (mAb) anthrax antitoxin for the treatment and prevention of inhalational anthrax used in a bioterror attack. Study results were highlighted in poster presentations at the ASM Biodefense and Emerging Diseases Research meeting being held this week in Washington, DC. Obiltoxaximab is in late stage development, and is a candidate for future acquisition into the Strategic National Stockpile, the U.S. government’s repository of critical medical supplies for biowarfare preparedness. 

In the first presentation, results of four studies conducted in a monkey treatment model of inhalational anthrax were discussed; survival to 28 days was the primary endpoint. There was significant survival for the majority of obiltoxaximab treatment groups (5/8) over placebo groups (p<0.025). Statistically significant obiltoxaximab survival benefit versus placebo were demonstrated across a range of disease severity. Survival outcomes were shown to be dependent on severity of disease prior to treatment as measured by the amount of bacteria in the blood; 16 mg/kg of ETI-204 was determined to be the maximally efficacious dose.

A second presentation by Elusys demonstrated significant efficacy in two studies in monkeys. In both studies, obiltoxaximab was dosed via a single intramuscular injection (IM) at 16 mg/kg, 18-48 hours following challenge with aerosolized B. anthracis spores. Survival to day 28 or day 56 was the primary endpoint. In the first study, obiltoxaximab survival was 100%, 83% and 50% at 18, 24 and 36 hours compared to zero survival in the placebo group. In the second study, obiltoxaximab survival was 93%, 43%, and 25% at 24, 36 and 48 hours compared to 10% in placebo.  IM obiltoxaximab was significantly efficacious compared to placebo when given at 18 and 24 hours post-exposure, and provided increased protection compared to controls at 36 and 48 hours post-exposure.  Obiltoxaximab prevented development of Protective Antigen (PA) toxemia and bacteremia in the majority of animals when administered at 18 or 24 hours post challenge, and effectively neutralized serum PA in animals treated at 36 and 48 hours post challenge.

“Elusys is pleased to be presenting important data on the efficacy and pharmacology of obiltoxaximab,” said Elizabeth Posillico, PhD, President and Chief Executive Officer of Elusys. “We have completed the nonclinical efficacy studies required for filing our biologics license application and are delighted and confident that our BLA will be submitted in the coming weeks. We believe that obiltoxaximab can be an important addition to the Strategic National Stockpile to help protect the U.S. public from this deadly bioterror threat.”

The third poster presented by the company examined the pharmacology of obiltoxaximab in animal models following anthrax infection. Obiltoxaximab was shown to rapidly reduce free Protective Antigen (PA) in serum, a critical component in anthrax virulence. The company’s anti-toxin also enabled host-directed bacterial clearance when given after the onset of systemic inhalation anthrax infection. In addition, treatment with obiltoxaximab did not interfere with development of adaptive immunity, which is expected to provide protection from future infection.

Inhalation anthrax is a life-threatening infectious disease caused by the bacterium Bacillus anthracis and remains one of the nation’s top biowarfare threats. Much of the morbidity and mortality of anthrax can be attributed to anthrax toxins. Inhaled anthrax is often fatal, despite treatment with antibiotics. In the 2001 anthrax letter attacks, inhalational anthrax had a fatality rate of approximately 50% in humans infected even when victims were given antibiotics and supportive hospital care.

Obiltoxaximab is formulated as a solution and is the only anthrax anti-toxin in advanced stages of development that is being investigated for intravenous (IV) treatment and intramuscular (IM) prophylaxis administration. IV administration is being evaluated for the treatment of patients who have established infection and are symptomatic for anthrax disease, as well as for prophylaxis. Prophylaxis includes immediate pre-exposure prophylaxis (as in the case of emergency personnel responding to an event) and post-exposure prophylaxis (when there is reason to believe a person may have been exposed to anthrax but prior to signs/symptoms of infection). The ability to administer an anti-toxin via IM injection may provide a valuable alternative to IV injection in an emergency where medical resources and personnel may be limited or when IV administration is not feasible.

About Obiltoxaximab (ETI-204)
Obiltoxaximab (ETI-204) is a high-affinity monoclonal antibody that is in the late stages of development for the treatment and prevention of inhalational anthrax, a top bioterror threat. All pivotal animal efficacy studies and human safety studies required for Biologics License Application (BLA) filing, the U.S. Food and Drug Administration (FDA)-required regulatory submission, have been conducted, and a BLA is in preparation. A commercial scale manufacturing process has been established.  

Obiltoxaximab efficacy and safety have been studied in animal models of inhalational anthrax and safety has been evaluated in 470 healthy human volunteers. Six studies assessing safety and pharmacokinetics of IV administration of obiltoxaximab in adult volunteers have been completed. The more common treatment emergent adverse events occurring in clinical trials of obiltoxaximab include somnolence, upper respiratory tract infection, headache, infusion site swelling, erythema or pain, nausea, urticaria, erythema, nasal congestion, back pain and oropharyngeal pain.

Obiltoxaximab was granted Fast Track status and Orphan Drug Designation by the FDA.

This program is supported with federal funds from the Office of the Assistant Secretary for Preparedness and Response, Biomedical Advanced Research and Development Authority (BARDA), the Department of Health and Human Services (HHS) under Contract Nos. HHSO100201000026C and HHS0100201100034C.

About Elusys Therapeutics, Inc.
Elusys Therapeutics, a private company based in Pine Brook, NJ, is focused on the development of antibody therapeutics for the treatment of infectious disease. Elusys has been engaged in the development of obiltoxaximab, an anthrax biowarfare countermeasure, since 2002. The company has received multiple grants and contracts totaling over $200 million to support the development of obiltoxaximab to protect people in the event of an anthrax attack. Today, obiltoxaximab has advanced to the final stages of development, and is closer to achieving the company’s goals of receiving FDA licensure and becoming part of the Strategic National Stockpile. For more information, please visit

SOURCE: Elusys Therapeutics