THE CHIEF executive of Merrion Pharmaceuticals resigned suddenly yesterday.

In a brief statement, the Dublin-listed drug development business said John Lynch “has decided to resign as director and chief executive . . . to pursue other business interests”.

Following a board meeting later yesterday, the company announced that chief financial officer Jonathan O’Connell would take over as chief executive.

Mr O’Connell will continue to function also as chief financial officer, a role he has occupied since November 2005.

In a statement, chairman Paddy O’Sullivan said: “Jonathan O’Connell is an outstanding choice for chief executive and has the ideal credentials to lead Merrion forward.”

Merrion uses a proprietary technology to develop oral versions of existing medicines. The company, which reported pretax losses of €2.5 million for 2010, has been working with diabetes specialist Novo Nordisk to develop oral forms of a number of its drugs.

In 2008, the Danish group agreed to pay Merrion for the cost of its development work, provide €45.7 million in staged payments and give it a share in the royalties on sales of any product brought to market from the collaboration.

Merrion has also been developing its own breast cancer drug Orazol.

Mr Lynch has been with Merrion Pharmaceuticals since it began operations in 2004 to commercialise a number of technologies bought from Irish biotech group Elan. He has been chief executive since early 2008.

Merrion chairman Patrick O’Sullivan said: “John has played a huge part in Merrion’s growth to date and his commitment and focus have been inspiring. We wish him well in the future.”