AstraZeneca raised its 2014 sales forecast for the second quarter in a row yestesrday, as the delayed arrival of generic copies of its Nexium drug in the United States kept cash flowing from the heartburn and ulcer pill.

Britain’s second biggest drugmaker, which saw off a $118 billion takeover bid from Pfizer in May, now expects revenue to grow in low single digits at constant exchange rates this year, after previously being seen flat.

The upgrade follows a better-than-expected sales performance in the third quarter, helped by the Nexium factor.

Chief executive Pascal Soriot, who has fought hard to prove AstraZeneca has a strong independent future and does not need the kind of mega-merger offered by Pfizer, said he would use the better financial outlook to accelerate investment in new drugs.

The company will also get an upfront payment of $325 million from Aegerion Pharmaceuticals, after agreeing to sell the US company its rare disease drug Myalept.

AstraZeneca now expects “core” earnings per share (EPS), which exclude some items, to fall around 10 per cent this year at constant rates. That is better than anticipated previously, but is offset by an anticipated currency hit of about five per cent.

The biggest hopes are centred on cancer, where AstraZeneca is vying with rivals such as Bristol-Myers Squibb, Merck & Co and Roche in the hot area of immunotherapy treatments, which boost the immune system to fight tumours.

AstraZeneca presented promising early drug data at a cancer conference in September and more results are expected at an investor day on November 18, just eight days before Pfizer is allowed to make a fresh bid under British takeover rules.

Although the pipeline momentum is certainly building, AstraZeneca still faces major challenges, with a raft of patent expiries expected to pressure sales and profits until 2017, according to analyst forecasts.