AstraZeneca's potential blockbuster heart drug Brilinta has received the backing of a US advisory panel just as the drug giant increased 2010 earnings targets for a second time this year following a strong performance from emerging markets and key drugs in the second quarter. The US Food and Drug Administration (FDA) Cardiovascular and Renal Drugs Advisory Committee recommends the FDA approve Astra's experimental blood thinner, providing a huge boost for the London-listed firm.Last night's decision helps to progress what is expected to be a $1.6bn grossing drug by 2015, says Jonathan Jackson at Killik Capital. Schizophrenia pill Seroquel, currently the firm's biggest seller, generates $2.1bn annually.Results, published this morning, revealed forecasts for full-year core earnings have shifted up to $6.35-$6.65 a share, up from April's guidance of $6.05-$6.35.Revenue was pretty much in line, inching up 1% on a constant exchange rates (CER) basis to $8.18bn, or 3% on an actual basis, as 16% growth in emerging markets offset a 4% decline in US revenue due to generic competition for Toprol-XL and Pulmicort.Sales of cholesterol drug Crestor surged by 23% in the second quarter at CER to $1.43bn. They were up 24% in the US.Net profit grew to $2.12bn from $1.71bn, though core operating profit was unchanged on a CER basis at $3.65bn as increased revenue and lower operating costs were cancelled by lower other operating income, including some sales made the previous year. Core earnings rose 9% at CER to $1.79 a share."Our second quarter performance reflects continued strong growth in our emerging markets and good performance for key brands Crestor, Seroquel and Symbicort," chief executive David Brennan said."While revenue and core EPS comparisons become more challenging in the second half of the year, we have increased our full year financial targets."In a widely-anticipated decision, Astra is doubling its share buy-back scheme to $2bn in 2010. It's bought $516m of its own shares so far this year.Shareholders will receive a first interim dividend of $0.70 (44.9p).