Jeffrey Blumer reviewed the manuscript and provided excellent advice. Footnotes Publisher’s Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. completed dosing without serious adverse events. Two subjects in the 10-day cohort stopped at Day 9 after developing respiratory and systemic symptoms, and a third experienced a decrease in FEV1 (Forced Expiratory Volume in 1 second) after the 9th dose and a further decline after the 10th dose. Plasma DAS181, in the 10-day cohort, peaked and began falling before the last dose. Antibodies, predominately IgG with neutralizing activity, were detected in 15/18 subjects by Day 30. The highest IgG concentrations were in the 10-day cohort. The respiratory adverse events occurring after seven days and rapid drug clearance during continued dosing are consistent with the induction of DAS181 antibodies. This could preclude use of Rabbit polyclonal to ACE2 this medication for longer than seven days or for repeated courses. (These studies have been registered at ClinicalTrials.gov under registration nos. NCT 00527865 and NCT 01651494.) Keywords: Influenza, Parainfluenza, Sialidase, DAS-181 1.0 INTRODUCTION Influenza vaccines have limited effectiveness (1); this and the increasing resistance to influenza antivirals emphasizes the need to develop alternative approaches (1,2). DAS181 is such an alternative; it targets the sialic acid adornments on respiratory epithelial cells to which influenza and parainfluenza viruses bind and has the potential for preventing and treating infections caused by both viruses. DAS181 is a recombinant sialidase, derived from fused to an anchoring domain from the binding sequence of human amphiregulin (3). Administered by inhalation, DAS181 removes sialic acid from the respiratory epithelium (4) and thereby prevents the binding of influenza (5,6) and parainfluenza (7) viruses. This potentially could provide prophylaxis and treatment for all strains of influenza, including those that are resistant to neuraminidase inhibitors (8). Phase I trials of inhaled DAS181, conducted during its development, evaluated various doses, formulations and particle sizes (9). The primary adverse event noted during these trials was elevation of serum alkaline phosphatase (ALP) which was thought to result from the systemic absorption of the drug and de-sialylation of circulating glycoproteins (9). In addition, circulating, and neutralizing, antibodies were induced H4 Receptor antagonist 1 after a single dose of DAS181. Increasing the particle size from ~3.5 (DAS181-F01) to ~6 (DAS181-F02) reduced systemic absorption by depositing the drug higher in the respiratory tract, but did not eliminate elevation of ALP or antibody induction. DAS181-F02 was used in a randomized, double-blind, Phase II trial to determine the safety and tolerability of 10 mg of DAS181, inhaled once or over three days, in otherwise healthy adults with laboratory confirmed influenza (10). As compared with placebo, DAS181 reduced the influenza viral load in pharyngeal washes, but the reduction after a single dose was no longer significant after 48 h. After three daily doses, reduction in viral load remained significant for 48 h, or to Day 5. No significant differences were noted in time to resolution of clinical symptoms, and ALP elevations were H4 Receptor antagonist 1 noted in 19% of the multi-dose recipients. The results of the Phase II trial lead to the formulation of DAS181-F03 which has a particle size of 10 , designed to reduce deep lung deposition and the potential for systemic absorption, and DAS181-F04 which differs from DAS181-F03 only in the addition of MgSO4 as a counter ion excipient (Table 1). In hopes of increasing the effectiveness and duration of its antiviral effect, the dose of DAS181 was increased to 20 mg in the clinical trials reported here, and a duration of ten daily doses was assessed. In the first trial, DAS181-F03 was administered once (1 Day Cohort) or daily for ten days (10 Day Cohort); in the second trial DAS181-F04 was administered daily for three days (3 Day cohort). We assessed the toxicity, systemic absorption and immunogenicity of the two formulations dosed at 20 mg/d. The results of the two trials are combined in this report. Table 1 Composition of DAS181-F03 and DAS181-F04 Dry Powder
DAS18170.0865.06Active Pharmaceutical IngredientHistidine10.1110.09Prevent oligomerizationTrehalose9.238.50Moisture bindingMgSO40.006.16Counter ionCitric Acid2.532.13Counter ionSodium Acetate0.040.03Maintaining pHAcetic Acid0.030.01Maintaining pHWater8.008.00N/ATotal100.00100.00 Open in a separate window 2.0 MATERIALS AND METHODS We conducted three randomized, double-blind, placebo-controlled trials, each consisting H4 Receptor antagonist 1 of nine healthy adult volunteers who received DAS181 or placebo at a ratio of 2:1. The first cohort received a single dose of 20 mg DAS181-F03, or placebo. The second was to receive 20 mg DAS181-F03, or placebo, daily for 10 days. The third was administered DAS181-F04, 20 mg per day, or placebo, for 3 days. The DAS181 formulations were provided by Ansun Biopharma, Inc., San Diego, CA. The studies were authorized by the Johns Hopkins H4 Receptor antagonist 1 University or college Institutional Review Table, and written educated consent was from all.