The boss of a York-based healthcare company has left after a slump in revenues.

The Aptamer Group has announced the immediate departure of CEO and Director Dr Arron Tolley, who co-founded the business in 2008.

A company statement said the 45-year-old will leave his job with the firm after a period of gardening leave.

As a result, Chairman of the Board Dr Ian Gilham has become interim Executive Chairman and current CFO Dr Rob Quinn has become interim CEO. A search for a full-time CEO has started already.

Ian Gilham is an experienced CEO and Chairman of life science companies.

He is Chairman of AIM company Genedrive plc and was Chairman and Executive Chairman, of Horizon Discovery, which was listed on AIM, until its was bought by Perkin Elmer for £296m.

Prior to that, he was CEO of Main Market diagnostics company, Axis-Shield plc, which Alere Inc bought for £230m.

Rob Quinn is an experienced life sciences executive with highly relevant scientific experience working with publicly listed biotechnology and pharmaceutical companies, including as CFO of Silence Therapeutics.

Dr Gilham said: “I’d like to thank Arron for his achievements in building a company that is now providing its leading aptamer solutions to 15 of the top 20 pharmaceutical companies in the world. Alongside building the Optimer platform he has scaled the business through significant operational and corporate milestones, most significantly its AIM listing in December 2021. On behalf of the Board, I wish him well in the future.

“The Board is now focused on appointing an appropriate successor who will be able to lead Aptamer’s next phase of development and build on the foundations of the business to deliver shareholder value in the long term.”

Dr Quinn said: “I recognise the immense power of Aptamer Group’s technology and the impact it can have across the life sciences industry and I would like to thank Arron for everything he has contributed to the Company.

“I look forward to working closely with Ian, the wider management team and the Board as we look to drive revenues, grow the business, and to deliver value for shareholders.”

The Aptamer Group is noted for developing Optimer® protein binders which help drug companies develop new products.

Earlier this month, the company said it expected full year revenues in 2023 to be ‘materially below’ 2022. It blamed a ‘pipeline’ of existing business taking longer to convert, with much now falling in the next financial year.

“The Group is making cost savings in order to extend the cash runway,” it said.

It was also exploring a range of funding options to strengthen the balance sheet.

The company’s shareprice fell 13% following news of Dr Tolley’s departure.

Last summer, it moved to new premises three times its former size elsewhere at York Science Park.