With the report this week of the discovery of plasmid
mediated resistance to colistin, my thoughts turn to the Allergan/Astra-Zeneca
pipeline of antibiotics for highly resistant Gram-negative pathogens. Colistin
is our absolute last line against these superbugs. It’s a toxic drug that no one likes to use,
that most physicians don’t even know how to use correctly, and that is now
threatened with new, emerging resistance emanating from China. Allergan and
AstraZeneca are now marketing ceftazidime-avibactam in the US (soon to be
approved in Europe I hope) and are developing aztreonam-avibactam (at tectonic
speed). These antibiotics are active
against many (but not all) of the Gram-negative superbugs for which colistin therapy
is now used most often. We need these drugs to reach patients – and quickly.
And that’s where my concerns about the Allergan half of the equation come in.
Pfizer has proposed
an acquisition of Allergan to create shareholder value. This will be accomplished, in large part, via
savings in corporate taxes since the new company will be headquartered in
Ireland – where Allergan is currently located. The Newco will then avoid a large
portion of US taxes. The New York Times article
also notes that Pfizer may be planning a split into various bits and pieces
where innovative drugs will remain in one company while those facing imminent
or current generic competition will be part of another company.
So – you all remember Pfizer. The company was one of the few to market
penicillin just after World War II. It
was also the company that walked
away from antibiotics back in 2011 believing antibiotics to be subject to
regulatory uncertainty at the time and having no confidence that antibiotics
would provide a reasonable return on their research investment. AstraZeneca,
Allergan’s partner for the development and marketing of ceftazidime-avibactam
and aztreonam-avibactam, has also jettisoned
their antibiotic research group to form Entasis. They maintain an antibiotic development group
that is now a separate business
unit within AZ.
Allergan’s antibiotic group has no discovery research, but
does provide clinical development and microbiology support for their pipeline.
Will Pfizer-Allergan keep Allergan’s antibiotic group? Will they even keep their product
pipeline? Or will this all somehow be
re-split or even just jettisoned somehow after the merger?
My sources within Allergan are very convinced that Allergan
is committed to the antibiotics space – but will it remain committed under
Pfizer?
Given the threats of emerging resistance to the last line
antibiotics – the carbapenems – and now the new and potentially devastating
threat against colistin, the only backstop for many carbapenem-resistant
superbugs – it would be perfectly reasonable for the US government to insist
that Allergan’s antibiotic pipeline be kept intact and on time (or even
accelerated) for the US market post-merger. Will the US administration take an
aggressive stance here? Stay tuned.
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