Matt Emmens is a keen pilot. The chief executive of Shire Pharmaceuticals occasionally flies his own aircraft to business meetings from the group’s US headquarters in Wayne, Pennsylvania.

“Sometimes it’s just quicker to go on my own,” he told The Times last week during a fleeting visit to the UK.

It’s the same nononsense approach that Mr Emmens has applied to Shire. Since joining in 2003, he has helped to build the company into the UK’s third-largest pharmaceutical business and one of the fastest-growing in the world.

To many in the industry, Mr Emmens, a softly spoken American, is in an enviable position. While larger drug companies struggle to fill their pipelines with new medicines as patents on existing ones expire, Shire has seven on the market, five more awaiting approval from regulators and a further seven in development. That’s not bad when you consider that several companies more than ten times Shire’s size have virtually nothing in late-stage development. “It’s a very healthy business,” smiles Mr Emmens.

Shire, which has effectively evolved into a US company listed in the UK, is something of an enigma. Founded in 1986 in the UK, the group has grown from revenues of $7 million in 1997 to more than $1.6 billion (£820 million) in 2005, swallowing up nine other companies as it races up the FTSE.

Since taking the reins, in 2003, Mr Emmens has seen Shire’s share price quadruple and the group, which now employs 3,500 people, reach a valuation of about £5.5 billion. Moreover, the company has $1 billion in cash and is debt free. So how did he do it?

After a 34-year career in the pharmaceutical industry with companies including both the American and German Mercks, Mr Emmens certainly didn’t lack experience, but he puts Shire’s success down to the adoption of what he calls a “specialty pharmaceutical model”.

He has focused on licensing in drugs for niche therapeutic areas with a market potential of $300 million to $400 million in annual sales, which is about a third of the size of the “blockbuster” $1 billion-plus treatments that typically appeal to big pharmaceutical companies such as AstraZeneca, Pfizer or GlaxoSmithKline.

“I like that specialty space - it’s a sweet spot,” Mr Emmens says, adding that it is big enough to develop a viable business while remaining below the radar of hungrier companies.

Much of Shire’s growth has been driven by its range of amphetamine-based drugs for attention-deficit and hyperactivity disorder (ADHD) - a rapidly growing, albeit controversial, market among both adults and children, especially in the US.

Adderall XR alone, the group’s top-selling product for the condition, generated 46 per cent of revenues in 2005 and is a serious challenger to Ritalin, a rival product produced by Novartis, the Swiss pharmaceutical group.

However, Mr Emmens denies any suggestion that Shire is overreliant on the drug. “I don’t see much competition and it’s a hugely undertreated condition,” he says. “This is a life-changing drug.”

Adderall XR is due to go off patent in 2009, but a successor drug called Vyvance, which Shire has developed with the American group New River Pharmaceuticals, is awaiting approval from US regulators at the end of this month. “We are confident it will be approved,” Mr Emmens says.

The company is also hoping for a spring launch of Lialda, a drug for ulcerative colitis - a disease that Mr Emmens says represents an $800 million market.

Other leading Shire products that are already on the market include Carbatrol, for epilepsy, and Fosrenol, for bone disease.

Shire does not develop its own drugs. Instead, it tends to buy them in from elsewhere, opting for products that use known science. This is a way of reducing the chances of drugs failing in late-stage development because of unknown side-effects, the bugbear of all drug companies, which can be forced to write off billions of dollars in development costs and years of research at a stroke.

Shire’s acquisitive nature has also given it an unusual culture, which Mr Emmens claims has allowed it to be more flexible than larger competitors. “We are an acquisitive company, but we are open to allowing people to do things their own way and maintaining their own entre-preneurial culture,” he says.

The specialty space also allows Shire to get by with a smaller and less expensive sales-force because the number of physicians who prescribe these drugs is limited. So far, it’s been a recipe for success, but things may get more difficult, Mr Emmens admits. Struggling rivals have spotted the opportunity and are starting to stray into the same space.

“Everyone is after those same products, the prices are going up and big pharma is coming after them too,” he says.

So how can Mr Emmens ensure that Shire is not outmanoeuvred by larger and wealthier rivals?

In 2005, he paid $1.5 billion for Transkaryotic Therapies, a Boston-based company with new protein-based drug technologies. It will be a while before Transkaryotic provides a return on the investment, but Mr Emmens is confident it will provide Shire with a pipeline of new products for years to come.

Shire is also likely to make further acquisitions. Many expect the company’s next target to be New River, with which Mr Emmens struck a partnership deal in 2004. He declines to comment on the prospect of a takeover, which would help Shire to reap the full benefits of Vyvance, but he sounds coy.

“We took [out] an option on the drug,” he says. “And anything else we do remains to be seen. The drug is now submitted and it looks like it works well and . . . we’ll see.”

Perhaps a more pressing concern is that, with all this success, Shire could become a takeover target itself. After all, it has many of the things that big pharma seeks. Earlier this year, rumours swirled about a possible takeover by AstraZeneca. Does the prospect keep Mr Emmens awake at night?

“It doesn’t concern me at all, beyond the welfare of our employees,” he replies. “Our best protection from a takeover is a strong share price. That is my job. But, beyond that, there is not much I can do about it.”

Mr Emmens says that he takes comfort from the fact that only a small number of companies could now afford to buy Shire. Throwing in a takeover premium, any bidder would need to stump up close to $15 billion to do a deal.

“Very few companies could now afford us,” he says.

Healthy career

1974Matt Emmens joined Merck & Co, where he held a range of sales, marketing and administrative posts
1992Helped set up Astra Merck, a joint venture between Merck & Co and Astra AB, the Swedish pharmaceuticals group
1999Joined Merck KGaA, a German company unrelated to Merck & Co, and established EMD Pharmaceuticals, the company’s US prescription business
2003Replaced Rolf Stahel, who was ousted in a boardroom dispute, as Shire’s chief executive.

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