US-based biopharmaceutical firm Elusys Therapeutics has completed patient enrolment in three Phase III safety studies of ETI-204, an anti-toxin being developed for the treatment of inhalational anthrax.
The company has also completed enrolment in an additional trial designed to assess the tolerability and pharmacokinetics of intramuscular (IM) administration of ETI-204 in 20 adult volunteers.
The first double blind, randomised, placebo-controlled trial is evaluating the safety and tolerability of a single intravenous (IV) dose (16mg/kg) of ETI-204 in 280 adult volunteers.
In this trial, patients are being randomised in a 3:1 ratio, with 210 subjects receiving ETI-204 and 70 subjects receiving placebo.
The study will also assess the bioavailability and clearance (pharmacokinetics), as well as the body's immune response (immunogenicity) of the anti-toxin.
The second double blind, randomised, placebo-controlled trial is designed to evaluate the safety and tolerability of repeat IV administration of ETI-204 (16mg/kg) in 70 adult subjects, as well as the pharmacokinetics and immunogenicity of the anti-toxin.
In this study, subjects are being randomised in a one-to-one ratio, to receive ETI-204 on days one and 14 and placebo on day 120 of the trial, or ETI-204 on days one and 120 and placebo on day 14.
Elusys president and chief executive officer Elizabeth Posillico said: "Our clinical trials include over 400 adult study subjects. We look forward to completing our clinical development programme and moving one step closer to BLA filing."
Elusys has also completed patient enrolment for a Phase III trial to assess the safety and tolerability of ETI-204 when given with oral ciprofloxacin, an antibiotic used to treat anthrax infection after inhalational exposure.
A total of 40 adult volunteers were randomised into two groups, in the first group they were given IV ETI-204 (16mg/kg) followed by a single dose of IV ciprofloxacin (400mg), followed by oral ciprofloxacin (750mg) every 12 hours on days two through eight and one final dose of the antibiotic on the morning of day nine, while the second group is receiving IV ETI-204 alone.
A total of 20 adult volunteers were enrolled in the fourth trial, which is designed to assess the safety and tolerability of IM injection of ETI-204.
Patients have been randomised to receive either IM administration of ETI-204 at doses of 4mg/kg (four subjects), 8mg/kg (eight subjects) or 16mg/kg (eight subjects), or matching placebo.
ETI-204 is a high-affinity, humanised and deimmunised monoclonal antibody, which targets the protective antigen of B anthracis and neutralises the lethal effects of anthrax toxins by binding to protective antigen.
It previously obtained fast-track status and orphan drug designation from the FDA.
Inhalation anthrax is a life-threatening infectious disease caused by the bacterium Bacillus anthracis.
The company said that ETI-204 is formulated as a solution and is the only anthrax anti-toxin in advanced stages of development that is being investigated for IV treatment and IM prophylaxis administration.
ETI-204 is a potential target for future acquisition into the Strategic National Stockpile, the US Government's repository of critical medical supplies for biowarfare preparedness.
Image: Photomicrograph of a gram stain of the bacterium Bacillus anthracis, the cause of the anthrax disease. Photo: courtesy of CDC.