Drugmakers may be under pressure to cut prices in the developing world but selling HIV drugs in the West remains a lucrative and fast-growing business.

Independent market research firm Datamonitor said the HIV/AIDS market was set to undergo significant changes over the next 10 years as drugs that work through novel mechanisms and next-generation versions of existing drugs are launched.

Sales, as a result, should rise significantly from about $7.1 billion in 2005, benefiting a clutch of companies with promising new products, including Merck & Co Inc., Pfizer Inc., Gilead Sciences Inc. and Johnson & Johnson.

Most cases of HIV/AIDS occur in sub-Saharan Africa, where lack of funding means treatment is restricted and prices are under pressure, resulting in little if any profit for multinational drug firms.

Just this week Abbott Laboratories Inc., widely criticised for aggressive pricing of its AIDS medicines, agreed to slash the price of its Kaletra AIDS drug by more than half in more than 40 poor countries.

But at the same time the disease is also increasing in the developed world, with an estimated 2.1 million people in North America and Western Europe living with HIV in 2006, up from 1.9 million in 2004.

"Advances in antiretroviral therapy have turned HIV from a universally feared death sentence into a chronic disease with an average life expectancy similar to that of Type 2 diabetes," Datamonitor analyst Mansi Shah said.

"Because of this, attitudes towards HIV have become relatively blase amongst some groups."

Notable new types of drugs include Pfizer's maraviroc, a CCR5 inhibitor, and Merck's raltegravir, an integrase inhibitor, which are expected to be launched in 2007 and 2008 respectively.

They will complement new generation forms of existing drug classes, such as Johnson & Johnson's recently approved Prezista, a protease inhibitor.

Such products offer new treatment options for the growing number of patients whose disease no longer responds to existing drugs.

At the same time, other companies are developing improved fixed-dose drug combinations, including Atripla from Gilead, which combines the components of current drug cocktails into a single pill that can be taken once a day.

Atripla was launched in the United States last year and is expected to take market share from its two components Truvada and Sustiva, as well as competitor drugs such as GlaxoSmithKline Plc's Combivir, Datamonitor said.

The global market for all pharmaceuticals grew 7 percent last year to $643 billion, according to estimates from another market research company, IMS Health, released last month.

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