Eli Lilly, the world's fourth-largest diabetes drugs maker, aims to have the widest range of anti diabetic drugs in order to win a larger slice in the growing market.

The global $40 billion diabetes drugs market could be worth as much as $53 billion in 2016, making it the second-largest therapeutic area by sales in the pharmaceuticals industry after cancer, according to market research IMS.

"We have such a robust pipeline that we expect to have the broadest portfolio in our industry. With our late-stage development, we are present across the continuum," Enrique Conterno, the head of Lilly's diabetes business, told Reuters in an interview.

Lilly has 10.6% market share from drugs such as Humalog and Humulin. It currently trails Denmark's Novo Nordisk , France's Sanofi and U.S. giant Merck & Co., but with dozens of new drugs now being tested, the balance could shift easily.

Regulators are currently reviewing a marketing application for Lilly and Boehringer's shared drug empagliflozin, which belongs to a new class of oral drugs called SGLT2 inhibitors.

Lilly also plans to submit its experimental once-weekly injection dulaglutide, part of a class of medicines called GLP-1 agonists that includes widely used Byetta and Bydureon.

Being present in the two substance classes, in addition to new types of insulin under development, would put Lilly ahead of its rivals, Conterno said.

A broader portfolio would also open the door to more combination therapies, such as the Trajenta/empagliflozin cocktail that Lilly is eyeing, which are likely to play an increasing role in therapy.

As diabetes spreads quickly due to growing obesity rates, treatment of the disease is increasingly passing to general practitioners in large numbers from a smaller range of specialist doctors.

As a result anti diabetics makers are seeking to offer a broader range of treatments in order for their marketing costs to translate into prescriptions and revenues.

"You need a critical mass, to reach a larger number of primary care physicians with our resources and support programmes," Conterno said.

The same reasoning was behind Lilly's deal in 2011 to work with family-owned German drugmaker Boehringer, which has better access to primary care doctors across the world than Lilly.

Lilly is not alone in trying to partner up to diversify across substance classes.

Pfizer and Merck this week said they will co-develop Pfizer's diabetes drug ertugliflozin, both as a standalone product and in combination with other drugs, including Merck's blockbuster Januvia.

AstraZeneca and Bristol-Myers Squibb last year jointly acquired diabetes specialist Amylin, widening an existing alliance between the two major drugmakers.