AstraZeneca is to cut costs by $1 billion and increase its focus on cancer treatments after underlying earnings, hit by drug patent expiries, fell 12 percent in the first quarter, broadly in line with analyst expectations.

Chief Executive Pascal Soriot said on Friday he would sharpen the prioritization of investments and increase spending in oncology while cutting commercial and manufacturing operations.

The result would be a "material decline" in spending on commercial activities this year and next, with net annualized savings of $1.1 billion by the end of 2017. The changes will involve a $1.5 billion one-off restructuring charge.

There will be job losses, reflecting the fact that specialist cancer drugs require smaller sales forces than ones sold to general practitioners. AstraZeneca declined to give numbers but said most of the job cuts would be outside Britain.

The drugmaker, which saw off a takeover attempt by Pfizer in 2014, is forecast by analysts to suffer a trough in earnings in 2016 and 2017 as it continues to be hit by loss of exclusivity on key products.

Its biggest seller, the cholesterol fighter Crestor, will face generic competition in the all-important U.S. market from next week.

Deutsche Bank analyst Richard Parkes said the detailed cost savings plan "should help investors become more comfortable over AstraZeneca's ability to bridge the upcoming Crestor patent cliff".

Soriot is betting on new medicines to revitalize the business, particularly in cancer, but these will take time to prove themselves. They also need investment.

"When you have all these great opportunities you have to then support them," he told reporters. "This is where the investment is going - it is more clinical trials, essentially, and launch preparation."

Soriot said there would be increased news about its new medicines in 2016, including a number of regulatory decisions and data readouts, particularly in oncology.

HIGH BAR FOR M&A

The British group has bought in products to bolster its new drug line-up, including the recent acquisitions of ZS Pharma and Acerta Pharma, but Soriot said he was setting a high bar for future deals as the company's pipeline was now full.

He declined to comment specifically on whether AstraZeneca would consider getting into a bidding war with Sanofi over U.S. cancer treatment specialist Medivation.

To free resources for investment, AstraZeneca has been selling off rights to non-core drugs and such "externalization" deals helped to boost revenue by $550 million in the first quarter. AstraZeneca agreed a further deal this week to sell rights to its new gout drug for up to $265 million.

Soriot believes he can build a business with annual sales of at least $45 billion by 2023, up from $24.7 billion in 2015, though many analysts question this target, which was first set out during the takeover battle with Pfizer.

He has high hopes in the hot cancer area of immuno-oncology but here AstraZeneca is competing with several tough rivals, including Bristol-Myers Squibb, whose drug Opdivo has established strong early leadership.

First-quarter revenue at the British drug company rose 1 percent in dollar terms to $6.12 billion, generating core earnings per share, which exclude certain items, of 95 cents.

Industry analysts had on average forecast quarterly revenue of $5.93 billion and earnings of 94 cents a share, according to Thomson Reuters.

AstraZeneca reiterated that it expected a low to mid single-digit percentage decline in both revenue and core earnings at constant exchange rates for the full year.

(Editing by David Goodman and Susan Thomas)