Tuesday, November 24, 2015

Pfizer, Allergan and Antibiotics

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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