The deal would give AstraZeneca a majority stake of 55% and value the anti-cancer drug developer at approximately $7bn.

AstraZeneca (AZ) has agreed to acquire a 55% stake in Netherlands-based anti-cancer drug developer Acerta Pharma, backed by the regional government venturing unit BOM Capital, that could value the company at about $7bn. This would be the largest venture-backed exit of the year.

AZ has agreed to pay $2.5bn initially if the deal for a majority-stake closes as expected in the first quarter of 2016. Another $1.5bn will be paid either on receipt of the first regulatory approval for its main drug, Acalabrutinib, for any indication in the US, or the end of 2018, depending on which is first. AZ also has a $3bn option to buy the remaining shares.

Acerta is testing Acalabrutinib, a so-called BTK inhibitor, designed to interrupt the signalling process that B-cell cancers use to proliferate, and which could bring in $5bn a year at its peak if clinical trials work out, according to AZ in its press release.

Acerta Pharma raised $13m-14m in a first tranche of its $130-175m series A round in 2013 from Dutch region Brabantse Ontwikkelings Maatschappij’s BOM Capital and venture capital firms BioGeneration Ventures, Frazier Healthcare Ventures and OrbiMed Advisors, according to Fortune. BioGeneration Ventures started in 2007 as an initiative between the government’s Netherlands Genomics Initiative (NGI), Leiden University, bank ABN Amro and its former VC unit Forbion Capital Partners.

It also raised an undisclosed, reported at up to $375m, amount of series B funding in May, according to news provider Fortune, which meant US investors “significantly” diluted Biogeneration to “low single digit” percentage, according to one industry expert. Biogeneration was unavailable to comment at short notice.

By February 2014, BOM had invested €749,222 in Acerta, according to the answer to political questions.

Deal manager Mariette van der Velden-Roesink, senior investment manager for life sciences and health at BOM Capital, declined to disclose its investment but said the Brabant (Oss) region had been important in Acerta’s development.

She said: “Two of the entrepreneurs were former Organon scientists that – after the Schering Plough and MSD takeovers – took the opportunity to license the BTK inhibitor lead from MSD [Merck Sharp & Dohme, as US-based Merck is known outside of North America,] to develop in a new company in 2012, which soon thereafter was connected to the other (US) founders with the clinical expertise, leading to the start of Acerta in January 2013.

“So the Brabant (Oss) ‘region’ was very much a factor in this startup, which deserved our support but also soon attracted many American investors and has management and clinical operations in California [under CEO Dave Johnson].”

Allard Kaptein, Tjeerd Barf and Ahmed Hamdy co-founded Acerta and merged it with another startup, Aspire Therapeutics, according to their LinkedIn profiles.