AstraZeneca has unveiled plans to sell or partner infection and neuroscience units with combined 2013 sales of $3.5 billion and a basis in antibiotics and antipsychotics as well as an experimental Alzheimer's drug.

At the same time, Pascal Soriot, CEO of the Swedish-British drugmaker, announced faster-than-expected progress of the company's experimental cancer drugs.

He said four important experimental medicines would advance into late-stage clinical tests - two for cancer and two for breathing disorders, including the first of its closely-watched immunotherapy cancer drugs, MEDI4736.

The announcements follow reports AstraZeneca had spurned a $101 billion bid approach from Pfizer earlier this year. Declining to comment on the rumor, Soriot said he remained focused on sharpening AstraZeneca's portfolio.

The CEO told analysts he hoped to conclude deals quickly.

Analysts said they were impressed with the speedy progress on the oncology front, which is believed to be a key draw for Pfizer.

"These numbers highlight why the interest (from Pfizer) is there. AstraZeneca has been in transition, with much business and product development underway but little as yet is really visible," said Edison Investment Research analyst Mick Cooper.

"We think AstraZeneca will return to growth faster than many believe, which underlines Pfizer's opportune timing," he added.

Soriot, who took over as CEO in 2012, has been credited with rebuilding AstraZeneca's drug pipeline, although the new products will not come in time to halt a fall in sales and profits over the next three years due to generic competition.

First-quarter sales were flat at $6.42 billion, generating core earnings of $1.17 a share. Core operating profit fell 16% to $1.95 billion.