Shake-up at AstraZeneca as two immuno-oncology leaders leave

* Immune-boosting cancer drugs critical to company's future

* Iannone named new head of immuno-oncology drug development

* Next (Other OTC: NXGPF - news) up, Astra awaiting clinical trial news on Brilinta

LONDON, Jan 5 (Reuters) - AstraZeneca (NYSE: AZN - news) 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 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 (NYSE: PFE - news) 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)