LONDON, Nov 4 (Reuters) - Researchers at Roche ROG.VX have
developed a new weapon to fight hard-to-treat bacteria by arming
an antibody with an antibiotic to reach and kill bugs hidden
inside cells.
The approach is similar to an existing technique used by
scientists at the Swiss group's biotech unit Genentech, which
arms antibodies with a chemotherapy drug to tackle cancer. That
system led to the development of the breast cancer drug Kadcyla.
In a paper in the journal Nature, the Genentech team
reported their new antibody-antibiotic conjugate (AAC) killed
Staphylococcus aureus in mice that standard potent antibiotics
failed to destroy.
Drug-resistant strains of S. aureus, or MRSA, are an
increasing concern in hospitals, where they can be deadly to
vulnerable patients.
The new AAC is designed to be inactive until it enters a
cell, when enzyme activity releases the antibiotic.
In an accompanying Nature commentary, Wolf-Dietrich Hardt at
Zurich's Institute of Microbiology said it remains to be seen
whether the AACs would be as good at treating bacterial
infections in humans as in mice.
But the approach is seen as promising, since it should cut
the emergence of antibiotic resistance by reducing exposure of
other bacteria to active drug, while also limiting damage to the
body's beneficial microbes.
In addition, it may allow scientists to look again at past
antibiotic drug candidates that were deemed too toxic to use but
which might be tolerated if loaded onto a highly targeted
antibody "missile".
Swiss drugmaker Roche, which last launched an antibiotic in
1982, has recently stepped up investment in the field, amid
growing public concern about the emergence of drug-resistant
superbugs.