Expectation has been building for a decade that an era of personalized medicine will transform the global drugs business, but the reality is a slow start and an angry blame game between scientists, marketers and regulators.

Drug firms accuse regulators of imposing cumbersome and expensive licensing requirements they say hark back to an old model of drug discovery when one-size-fits-all drugs had to be tested on thousands of patients before going on sale.

I've been talking about personalized medicines since 1989, and I was passionate about it ... but 20 years later we have only made modest progress, said Arthur Higgins, chief executive of Bayer HealthCare BAYG.DE and head of Europe's Federation of Pharmaceutical Industries and Associations.

And to be honest I'm not so convinced we will make much progress in the future...unless things change, he said, adding that the first requirement was a new regulatory framework to allow more interaction between drug firms and regulators.

Speaking alongside Higgins at a pharmaceutical conference in London last week, Chris Viehbacher, chief executive of Sanofi-Aventis, joined the attack:

Regulatory decisions on safety have been more around protecting the interests of the regulators, he said. Making them more developed and transparent will mean, for patients, the right decisions are being made.

But drug licensing chiefs reject such criticism, saying they are ahead of the game with fast-track options for drugs aimed at new areas, and help for firms wanting to design slick clinical trials to speed the path of a personalized drug to its market.

IS INDUSTRY REALLY KEEN?

They say it is the drug firms themselves -- or more specifically their marketing managers -- that have been slow to embrace the idea of medicines tailored to patients' genetic profiles, unimpressed by the limited sales potential they offer.

The question mark is, is the industry dragging its feet? said Thomas Lonngren, director of Europe's drugs regulator the European Medicines Agency (EMEA).

When I talk to drug research directors, they really want to go for this, but when I talk with the marketing people they're not so keen because the numbers and the volumes go down. The pharmaceutical industry really has something to learn here.

The targeted nature of a personalized drug has obvious upsides for patients. Experts say many ordinary medicines only work for around half of patients, so a drug designed for a specific gene type that really works is far more attractive.

But for payers and national healthcare providers -- who have to buy these often pricey medicines from a budget designated for improving health in as many people as possible -- and for drug firms whose sales are limited, the benefits are less obvious.

The problem is that personalized medicines are the antithesis of the beloved blockbusters -- the mighty-selling drugs sold to everyone with a particular disease that delivered Big Pharma its fat profits in the past.

For example Erbitux, a cancer drug sold by Merck KGaA, Eli Lilly and Bristol-Myers Squibb, has a smaller market because only around 65 percent of patients have the right gene type to allow the drug to work on them.

KEEN OR NOT, WINNERS NEED TO GO FOR IT

Lonngren says pharmaceutical companies need to look more closely at risk benefit models to be coaxed into abandoning the blockbuster and embracing the search for a portfolio of personalized drugs which could deliver similar rewards.

And he says EMEA is ready to help. For life threatening disease areas the medicines regulator was prepared to take the risk and get the benefit of the product on the market, he said,

It would also look at staggering a new drug's approval process -- start narrow and then widen the indication -- to get it on sale more quickly.

Putting the blame game aside, drug company heads agree that facing up to personalized medicine, and seizing its benefits, is a necessity for drug companies who want to succeed.

Viehbacher said the model of the past 20 years was not really working and needed to be turned around to put the patient, not the payer, at the heart of a drug company's work.

And Higgins said an ability to deliver personalized drugs would be a defining features of future pharma winners.

Jonathan Peacock, chief financial officer of Novartis's pharmaceuticals division, said that after years of talking, action was starting to gain pace.

There is a real shift happening now, where pharma companies are operationalising the words personalized medicine, he said.

It's a mindset change -- and that change has to work its way through the organization. It's an evolution, but its starting to come together now.

(Additional reporting by Ben Deighton, editing by Ben Hirschler and Andrew Callus)