AstraZeneca PLC (LON:AZN) got a shot in the arm from broker Jefferies over prospects for a potential lung drug.
Jefferies upgraded the health giant to a 'buy' recommendation with a rise in its target price to 5800p from 5400p.
AstraZeneca is carrying out a late-stage study known as Mystic of a potential lung cancer treatment called durvalumab.
Prospects for the drug got a boost from news of the failure of a phase three lung cancer study with Opdivo at rival Bristol-Myers Squibb Co (NYSE:BMY).
Jefferies said: "We have upgraded AstraZeneca to 'buy' as we see a much higher probability of success and a larger market opportunity from the Mystic study than consensus implies.
"We see positive asymmetry with up to 39% upside in AZN shares if MYSTIC hits versus 10% downside if it fails."
Elsewhere, Exane BNP Paribas upgraded John Wood Group PLC (LON:WG.) to 'outperform' with an increase in its price target to 815p and Barclays Capita reiterated its 'overweight' rating.
Barclays said John Wood had sounded an optimistic note at an energy conference held by the broker about an industry recovery from low oil prices.
But it added that the upbeat sentiment had yet to turn into a tangible revenue stream.
Barclays also upgraded its price target on building company John Laing Group PLC (LON:JLG) to 315p from 270p, saying it believed the prospects for increases in Laing's net asset value were strong.
Meanwhile, investment manager Man Group (LON:EMG) benefited from an upgrade to 'buy' from Citigroup.
But shares in Mediclinic International PLC (LON:MDC) were on their sick bed, falling 23p or 2.35% to 956.5p, after the same broker downgraded the health group to 'neutral'.