* Trailing rivals, Roche seeking immunotherapy niches (Adds comments from lead study author, details on PD-L1 subgroup)

An immunotherapy cocktail from Roche helped slow a type of breast cancer where new treatments have proven elusive, data released on Saturday showed, offering positive news for the Swiss drugmaker as it chases medicines produced by its rivals.

U.S. President Donald Trump is scheduled to meet the chief executives of the biggest U.S. defense companies at Luke Air Force Base in Arizona on Friday to discuss how they can source more parts and materials domestically, people familiar with the meeting said on Friday.

* WTI in contango as Cushing stockpiles expected to rise (Updates with CFTC data)

Williams signed Mercedes-backed Briton George Russell for 2019 on talent alone and not for any financial considerations, the Formula One team's deputy principal Claire Williams said on Friday.

* Says he 'relished grappling with controversial issues' (Adds Breakingviews link)

A report on risks to the stability of derivatives markets posed by Brexit could lead to regulatory intervention, European Commission officials said on Thursday, dismissing warnings they could tumble off a cliff if Britain leaves the EU with no deal.

The following are mergers under review by the European Commission and a brief guide to the EU merger process:

Air France-KLM's new Chief Executive Ben Smith struck a pay deal with French unions on Friday, drawing a line under a protracted standoff that had led to costly strikes and the abrupt departure of his predecessor earlier this year.

European stocks ended a choppy trading session broadly flat on Friday but managed to eke out a weekly gain despite mixed third-quarter earnings and while the budget row between Italy's populist government and the European Union heated up.