By James DeGiulio —

Last
week, NexBio, Inc. announced the issuance of U.S. Patent No. 7,645,448,
entitled "Class of Therapeutic Protein Based Molecules."  The '448
patent, issued January 12, 2010, is the company's first issued U.S. patent.  The
patent covers NexBio's sialidase pharmaceutical compositions, including its
lead compound DAS181 (Fludase®) and methods of treating or preventing viral
infection by influenza and parainfluenza with such compositions.

Fludase® (at left) is
a recombinant fusion protein that inactivates sialic viral receptors on the cells
of the human respiratory tract, thereby preventing all types of influenza
(including H1N1) and other viruses from both infecting the human body and
amplifying in already-infected individuals.  Fludase® is currently undergoing a
Phase II clinical trial for the treatment of community-acquired influenza.  More
information on the clinical trial can be found here.

Current
antivirals target the virus particle and thus are limited by virus
resistance.  According to the
patent, NexBio's technology is not limited by virus resistance because its
compounds target the virus point of attachment and entry on cells, rather than
the virus itself.  The patent further discloses the use of these compounds to
enhance gene delivery for gene therapy applications.  Finally, the patent
contains several examples of synthesizing sialidase proteins and corresponding
functional assays.

The
21 allowed claims cover the peptides, pharmaceutical compositions, and methods
of treating or preventing viral infection.  Representative claims include:

1.  An isolated polypeptide comprising an amino acid sequence that begins at any of
the amino acids from amino acid 270 to amino acid 290 of the Actinomyces viscosus sialidase protein
sequence (SEQ ID NO:12) and ends at any of the amino acids from amino acid 665
to amino acid 901 of the Actinomyces
viscosus sialidase protein sequence (SEQ ID NO:12), wherein the isolated
polypeptide does not comprise the sequence extending from amino acid 1 to amino
acid 269 of SEQ ID NO:12 and wherein the isolated polypeptide has sialidase
activity.

7.  A pharmaceutical formulation comprising the isolated polypeptide of claim 1.

9.  A method of treating or preventing viral infection by influenza, comprising:
    applying
a therapeutically effective amount of the formulation of claim 7 to epithelial
cells of a subject.

James
DeGiulio has a doctorate in molecular biology and genetics from
Northwestern University and is a third-year law
student at the Northwestern University School of Law.  Dr. DeGiulio
was a member of MBHB's 2009 class of summer associates, and he can be
contacted at degiulio@mbhb.com.