Elusys Therapeutics Announces Publication Of Results From Five Clinical Trials With Its Inhalational Anthrax Antitoxin, ANTHIM® (obiltoxaximab) Injection

PINE BROOK, N.J., Sept. 14, 2016 /PRNewswire/ -- Elusys Therapeutics, Inc. (Elusys) today announced that the company published data on over 450 healthy adult subjects from five clinical trials used to support recent U.S. Food and Drug Administration (FDA) marketing approval of ANTHIM® (obiltoxaximab) Injection, its treatment for inhalation anthrax. The results are published online at Clinical Therapeutics. ANTHIM received FDA marketing approval in March 2016.  ANTHIM is indicated in adult and pediatric patients for the treatment of inhalational anthrax due to Bacillus anthracis in combination with appropriate antibacterial drugs and for prophylaxis of inhalational anthrax when alternative therapies are not available or are not appropriate.

ANTHIM should only be used for prophylaxis when its benefit for prevention of inhalational anthrax outweighs the risk of hypersensitivity and anaphylaxis. The effectiveness of ANTHIM is based solely on efficacy studies in animal models of inhalational anthrax. There have been no studies of the safety or pharmacokinetics (PK) of ANTHIM in the pediatric population. Dosing in pediatric patients was derived using a population PK approach. ANTHIM does not have direct antibacterial activity. ANTHIM should be used in combination with appropriate antibacterial drugs. ANTHIM is not expected to cross the blood-brain barrier and does not prevent or treat meningitis. ANTHIM was developed under the FDA's Animal Rule which requires human healthy volunteer safety and pharmacokinetic studies in addition to animal efficacy studies. The Animal Rule applies to approval of drugs and biologics intended to treat serious or life-threatening conditions caused by exposure to lethal or permanently disabling substances and for which clinical efficacy studies in humans are unethical or unfeasible.

The article, Pharmacokinetics and Tolerability of Obiltoxaximab: A Report of 5 Healthy Volunteer Studies, describes the safety, immunogenicity, and pharmacokinetic results from five clinical trials of ANTHIM:

• randomized, double-blind studies of obiltoxaximab versus placebo (Studies 1-3)
• open-label, parallel group study of obiltoxaximab alone versus obiltoxaximab and ciprofloxacin (Study 4)
• randomized, double-blind, placebo-controlled study involving administration of a second dose of obiltoxaximab 2 weeks and 4 months after an initial dose (Study 5)

Results from the two multiple-dose studies (Studies 1 and 2) demonstrated that obiltoxaximab exposure increased proportionally. Pharmacokinetic results were consistent across studies with a terminal half-life of 17 to 23 days, mean volume of distribution 6.3 to 7.5 L, and mean systemic clearance of 0.27 L/d, suggesting that hepatic metabolism and/or renal excretion are not critical to obiltoxaximab. Obiltoxaximab was generally well tolerated; hypersensitivity reactions were the most common adverse reactions in the safety clinical trials (studies 3, 4, 5) (34/320 or 10.6% versus 4/70 or 5.7% in subjects receiving placebo). Three (0.9%) cases of anaphylaxis occurred during or immediately after the infusion.

ANTHIM infusion was discontinued in 8 (2.5%) subjects due to hypersensitivity or anaphylaxis.  The most common adverse events were headache, pruritus, upper respiratory tract infection, cough, infusion site swelling, bruising and/or pain, nasal congestion, urticaria, and extremity pain. 

"These data, combined with previously reported efficacy data from animal model studies, further support the addition of ANTHIM to the therapeutic armamentarium in the treatment of inhalation anthrax," said Elizabeth Posillico, PhD, President and Chief Executive Officer of Elusys. "Based on the consistent results from five clinical trials in healthy volunteers, the pharmacokinetics of ANTHIM can be considered adequately characterized, a criteria of the Animal Rule."

In these studies, ANTHIM was administered intravenously (IV). Safety was characterized by physical exams, including examinations of the skin and infusion sites, study drug infusion discontinuation, and adverse events assessment, vital signs, electrocardiograms, laboratory parameters, and immunogenicity. Studies 3-5 were the primary safety studies and ANTHIM was administered at 16 mg/kg.

The full manuscript of the article is currently accessible on the Clinical Therapeutics website and will be published in the September issue of the journal.

In November 2015, Elusys was awarded a $45M delivery order from the U.S. government to produce ANTHIM for the U.S. Strategic National Stockpile, the U.S. government's repository of critical medical supplies for public health emergency preparedness.

ANTHIM is a monoclonal antibody that binds to the protective antigen (PA) component of anthrax toxin. ANTHIM's toxin neutralizing activity prevents entry of anthrax toxin into susceptible cells, avoiding further spread of the toxin throughout the body and the ensuing tissue damage that leads to death. ANTHIM is supplied as single-dose vials for IV infusion.

Anthrax is a life-threatening infectious disease caused by B. anthracis.  Cases of inhalational anthrax in humans can occur through intentional spread of B. anthracis spores as a biowarfare or bioterrorism agent. B. anthracis spores introduced through the lungs lead to inhalational anthrax, which is deadly in humans. 

IMPORTANT SAFETY INFORMATION

WARNINGS AND PRECAUTIONS
Hypersensitivity and anaphylaxis have been reported during the IV infusion of ANTHIM. Due to the risk of hypersensitivity and anaphylaxis, ANTHIM should be administered in monitored settings by personnel trained and equipped to manage anaphylaxis. Monitor individuals who receive ANTHIM closely for signs and symptoms of hypersensitivity reactions throughout the infusion and for a period of time after administration. Stop ANTHIM infusion immediately and treat appropriately if hypersensitivity or anaphylaxis occurs. Pre-medication with diphenhydramine is recommended prior to administration of ANTHIM. Diphenhydramine pre-medication does not prevent anaphylaxis, and may mask or delay onset of symptoms of hypersensitivity.

ADVERSE REACTIONS
The safety of ANTHIM has been studied only in healthy volunteers. It has not been studied in patients with inhalational anthrax. The most frequently reported adverse reactions were headache, pruritus, infections of the upper respiratory tract, cough, vessel puncture site bruise, infusion site swelling, urticaria, nasal congestion, infusion site pain, and pain in extremity.

USE IN SPECIFIC POPULATIONS
Pediatric Use: There have been no studies of the safety or PK of ANTHIM in the pediatric population.
To see the complete prescribing information for ANTHIM, click here.

The ANTHIM program was supported primarily 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 numbers HHSO100201000026C, fully funded at $140.9 million, and HHS0100201100034C, currently funded at $54.7 million.

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. In March 2016, the U.S. Food and Drug Administration (FDA) approved ANTHIM (obiltoxaximab) Injection (www.anthim.com), the company's monoclonal antibody (mAb) anthrax antitoxin, for the treatment of inhalational anthrax due to Bacillus anthracis in combination with appropriate antibacterial drugs, and for prophylaxis of inhalational anthrax when alternative therapies are not available or are not appropriate. Elusys has received over $240 million in development grants and contracts from the U.S. Department of Defense (DoD), National Institutes of Health (NIH) and BARDA. Current investors include Essex Woodlands Health Ventures LLC, Invesco Private Capital, Crescendo Ventures, MedImmune Ventures and Pfizer. For more information, visit www.elusys.com. 

SAFE HARBOR STATEMENT
This announcement includes statements that are forward-looking within the meaning of the Private Securities Litigation Reform Act of 1995. This release includes forward-looking statements. Any statements, other than statements of historical fact, including statements regarding our strategy, future operations, future financial position, future revenues, projected costs, prospects, plans and objectives of management, and any other statements containing the words "believes", "expects", "anticipates", "plans", "estimates" and similar expressions, are forward-looking statements. Such statements are based upon the current beliefs and expectations of management that are subject to risks, uncertainties and other important factors that could cause the company's actual results to differ materially from those indicated by such forward-looking statements. The guidance in this presentation is only effective as of the date given and will not be updated or affirmed unless and until the Company publicly announces updated or affirmed guidance.

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SOURCE Elusys Therapeutics, Inc.

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