The world's first venture capital fund dedicated to finding new ways to prevent and treat dementia has raised $100 million with the backing of the British government and several of the world's leading drugmakers.

The Global Dementia Discovery Fund is unique in focusing on a single difficult to treat disorder and in bringing together industry and government.

Drug companies involved include GlaxoSmithKline, Johnson & Johnson, Eli Lilly, Pfizer and Biogen Idec.

The initiative, announced by Britain's health minister Jeremy Hunt at a meeting in Geneva on Tuesday, follows a Group of Eight (G8) nations conference in London in December 2013 that set a goal of finding a cure or effective treatment for Alzheimer's and other forms of dementia by 2025.

GSK's head of pharmaceutical research Patrick Vallance told Reuters the 2025 goal was "hugely ambitious" but that pooling resources through the new fund to back promising ideas from academic groups and small biotech firms would help to accelerate research.

"It's tough to crack but the science is moving," Vallance said. "People are now beginning to look at subsets of dementia and the genetics of neurodegeneration, so there are real opportunities."

Venture capital funds are a common source of finance for high-risk, early-stage life science research, but the new fund is the first to focus solely on dementia.

In addition to providing financial support, research projects that secure its backing will gain expert advice during the critical early stages of research, with charity Alzheimer's Research UK also involved alongside industry.

Individual pharmaceutical companies wanting to go on to develop particular projects commercially will be able to bid for rights to do so, with money raised from the bidding process to be reinvested in the fund.

The British government, as project leader, is contributing $22 million, while GSK is putting in $25 million and J&J $10 million, with further money coming from other companies.

Dementia, which can be caused by many kinds of illnesses, affects close to 50 million people worldwide and is set to reach 135 million by 2050, according to non-profit campaign group Alzheimer's Disease International. There is still no treatment that can slow the progression of Alzheimer's. Current drugs can do no more than ease some of the symptoms.