With combined sales from the top HIV treatment on the market, Atripla, and several other drugs, Gilead Sciences leads the antiviral market, closely followed by Bristol-Myers Squibb, Roche and Merck & Co.

That is the key point in a report from Kalorama Information, the healthcare market research firm, which notes that the market for all anti-infectives reached $53 billion in 2011. It points out that Atripla (efavirenz/tenofovir/emtricitabine) is expected to bring in $3.2 billion in sales in 2011 and the HIV drugs Truvada (emtricitabine/tenofovir) and Viread (tenofovir), plus the hepatitis B drug Hepsera (adefovir) are performing well.

However, in a highly competitive market, other companies are gaining, the analysis notes. B-MS is second, driven by its nucleoside analogue Baraclude (entecavir) for hepatitis B; its sales have grown from $257 million in 2007 to $1.1 billion now. As for the firm's HIV drugs, the Sustiva (efavirenz) franchise and Reyataz (atazanavir) are growing steadily.

Roche holds the third market position overall, helped by Pegasys (peginterferon alfa-2a), for hepatitis B and C, the transplantation product Valcyte (valganciclovir) and the influenza jab Tamiflu (oseltamivir). At the end of last year, the Swiss major announced plans to acquire the USA's Anadys Pharmaceuticals, a hepatitis C specialist, for around $230 million.

Kalorama notes that GlaxoSmithKline alone accounted for 25% of the antiviral market in 2009, but has since declined due to patent expirations.  on key products. However its HIV joint venture with Pfizer, ViiV Healthcare, accounted for one-tenth of the antiviral drug market in 2011.