The deal – which will see Heptares get $189m (€178m) per G protein-coupled receptor (GPCR) targeting compound it identifies – is designed to bolster Pfizer’s candidate drug pipeline.
The US – but possibly soon to be Irish - drugmaker will also buy $33m worth of Sosei shares under the agreement.
Pfizer did not name any specific disease areas that Heptares will look at, but did say the agreement will cover up to 10 potential drug candidates.
The partnership follows just a week after Israeli drugmaker Teva Pharmaceutical Industries partnered with Heptares to develop treatments for migraine using its structure-based drug design platform, known as StaR.
Big Pharma partners
The firm also has a platform technology deal with Morphosys that sees it supply its German partner with GPCRs against which antibodies are generated using the Ylanthia discovery platform.
The various deals are in keeping with the strategy outlined by Sosei when it paid Heptares’ former owners - MVM Life Science Partners, Clarus Ventures, Novartis Venture Fund, Takeda Ventures and the Stanley Family Foundation - $400m for the UK firm in February.
At the time Sosei said “the acquisition has no effect on existing partnerships, and indeed the partnering strategy is to continue” and explained that Heptares would continue to operate as a largely autonomous unit.
This was echoed by a Heptares spokesman who told us "When Heptares was acquired, we were encouraged to continue with our successful business development and partnering strategy. Sosei brings additional technology, corporate development expertise and high level networks that complement our own capabilities."
He rejected the suggestion Heptares' ability to attract Big Pharma partners was partly a legacy of in-house R&D cuts - Pfizer shut down its UK research campus in 2011.
Instead he said: "Pharma companies have exceptional research in certain areas. Heptares brings something that they do not have, which is unique capability to enable structure based drug design for GPCRs."