LONDON (Reuters) - AstraZeneca (>> AstraZeneca plc) has appointed a new leader for its all-important immuno-oncology drug development operation after the departure of the previous head for personal reasons, the British-based drugmaker said on Monday.

Rachel Humphrey left the company at the end November and was replaced last month by Robert Iannone, a member of the global medicines development team, a spokeswoman said in response to inquiries. Her departure was not announced at the time.

Humphrey's exit coincides with the loss of another leader in immuno-oncology, albeit from a different part of the firm. Peter Emtage, who was involved in early research at AstraZeneca's unit MedImmune, was appointed to a senior position at biotech company Intrexon (>> Intrexon Corp) on Dec. 4.

AstraZeneca said the two departures were a coincidence and the company's work in immuno-oncology was proceeding at full steam, with no problems with any programmes. "It's business as usual," the spokeswoman said.

The drugmaker, which saw off a $118 billion takeover attempt by Pfizer (>> Pfizer Inc.) last year, is banking on new cancer medicines to help revive its fortunes.

It is also hoping for an imminent boost to its heart drug Brilinta from results of a clinical trial - known as PEGASUS - assessing the medicine's use in patients who experienced a heart attack 1-3 years ago. That group could more than double the number of patients eligible for Brilinta.

(Reporting by Ben Hirschler; Editing by Pravin Char)

Stocks treated in this article : Pfizer Inc., AstraZeneca plc, Intrexon Corp