The latest surge for the UK company came after a trading update as traders built on the positive mood seen after tech giants Apple and Facebook delivered better-than-expected updates on Wall Street on Wednesday night.
The FTSE 100 Index was 28.3 points higher at 6703, with the top flight remaining in positive territory despite a lacklustre start to trading in New York.
The pound held firm against the US dollar and euro, at 1.68 and 1.21 respectively.
Among the biggest risers, mining giant Anglo American rose 19.5p to 1566.5p after its first quarter update showed an 18% year-on-year rise in copper production.
The better-than-expected performance gave a boost to other stocks in the sector as rival Rio Tinto cheered 29.5p to 3278.5p.
AstraZeneca's shares have now surged by around 12% this week after speculation last weekend linked it to a possible takeover approach from US firm Pfizer.
The firm was silent on the bid interest but stock still rose 3% or 132.5p to 4175p as it confirmed it will advance four drugs in oncology and respiratory disease for late-stage testing.
Revenues for the quarter were up 3% at constant exchange rates as Astra said it was on track to meet its financial guidance for this year.
Other big risers included fellow pharmaceuticals company Shire, which climbed 59p to 3248p. It was also a positive session for airline stocks as low-cost carrier easyJet improved 13p to 1699p and British Airways owner International Airlines Group lifted 6p to 413.3p.
Consumer goods company Unilever was among the biggest fallers in the top flight after it reported slower growth in emerging markets, albeit with a rise of 6.6% in revenues against 8.4% during the previous quarter.
Overall turnover for the group decreased 6.3% as the stronger euro resulted in a steeper-than-expected negative currency impact of 8.9%.
Shares were 2% or 44p lower at 2590p, even though sales growth excluding currency movements was 3.6% higher, with volumes up 1.9% and prices 1.6% stronger. City analysts had been expecting a 3.3% rise in the overall figure.
Barclays shares were also closely watched in a session when shareholders voiced their displeasure at last year's increase in its bonus pool, at a time of lower profits and a reduction in its dividend since 2008.
The biggest FTSE 100 risers were Smith & Nephew up 29.5p at 909p, AstraZeneca ahead 132.5p at 4175p, InterContinental Hotels up 43p at 1992p and Petrofac ahead 30p at 1438p.
The biggest fallers were Travis Perkins down 69p at 1763p, Associated British Foods off 97p at 2865p, Ashtead down 28.5p at 848.5p and Unilever off 44p at 2590p.