Sales of Gilead Sciences’ two hepatitis C blockbusters - Sovaldi and Harvoni -  have sent the firm’s fourth-quarter profits soaring four-fold, though its shares took a hit over the disclosure that 2015 revenues will be hurt by deep discounts in the USA.

The figures were pretty spectacular with net income rising to $3.49 billion, from $791 million, while product sales jumped 137% to $7.22 billion. Sales of Sovaldi (sofosbuvir), which costs $1,000 a pill in the USA, came in at $1.73 billion, lower than analyst estimates.

In its first quarter on the market, the combo Harvoni (ledipasvir/sofosbuvir) brought in $2.11 billion, higher than forecast. However, shares in Gilead fell 4.8% after hours as the company revealed discounts in the USA for Harvoni and Sovaldi will be around 46 percent this year, up from 22% in 2014.

Gilead is fighting a price war in the USA with AbbVie and its recently-launched HCV combo Viekira Pak (ombitasvir/paritaprevir/ritonavir), as they fight to get exclusivity for their treatments with Medicaid programmes, pharmacy benefit managers  and health insurers.  

Elsewhere, Gilead’s HIV franchise also performed well. Its once-daily, single pill Stribild - a combination of elvitegravir, cobicistat, emtricitabine and tenofovir - soared 89% to $385 million, while the triple combo Atripla (efavirenz/tenofovir/emtricitabine) was fairly flat at $925 million. Sales of Truvada (tenofovir/emtricitabine) were up 10% at $897 million.

The company also announced a $15 billion share buyback, on top of an existing $5 billion repurchasing plan, and said it will begin paying a quarterly dividend of $0.43 a share. Some observers feel this means Gilead will not be going after any big deals for a while but on a conference call chief financial officer Robin Washington said the buyback does not “in any way prevent us from investing in our business, our pipeline or M&A”.