Together, they will work on the discovery and development of novel anti-infective medicines, using the natural product compound collection and chemistry capabilities of its services division, BioFocus DPI.
The two firms are already working together in an ongoing osteoarthritis alliance, although this is Galapagos' first collaboration with an external firm beyond its core area of expertise - bone and joint diseases.
"It shows that Galapagos can generate significant business in new therapeutic areas," said Onno van de Stolpe, Galapagos' CEO.
Specifically, Galapagos will grant GSK options to license product candidates that are directed against up to six anti-infective discovery targets.
Galapagos will be responsible for the discovery and development of natural product small molecule drug candidates through to clinical proof of concept, at which point GSK can choose to bring them through to commercialisation.
Out of the agreement, Galapagos stands to pocket upfront fees of up to €3.5m from GSK, depending on the number of programmes undertaken, in addition to development and regulatory milestones payments for each product candidate, to a value of up to €95m. For any drugs that reach the market, Galapagos could be eligible for a further €120m in sales milestone payments and would also receive royalties on revenue from any co-developed products.
"This alliance fits within our strategy of executing risk/reward sharing deals with big pharma and at the same time underscores our M&A approach and successful integration of DPI into the BioFocus service division," said van de Stolpe.
In October, Galapagos penned 'by far' its biggest ever deal, with Johnson & Johnson (J&J) committing an estimated €1bn to a joint arthritis research programme.
The two-part deal has quite a complicated structure and incorporates both an alliance part and a part concerning Galapagos' own internal R&D programmes to develop rheumatoid arthritis (RA) drugs.
The bottom line though, as van de Stolpe told DrugResearcher.com at the time, is that the company estimates it will receive a total of €1bn for around five or six first-in-class drugs.
The deal dwarved the alliance that Galapagos expanded with GSK around the same time - worth around €180m - although as Van de Stolpe pointed out, that deal was concerned with much earlier stage research.