The LSE said the tie-up would be an "industry-defining combination" with substantial revenue and cost benefits.
The talks, first announced on 23 February, are still "ongoing".
It comes as the UK stock exchange company announced a 31% rise in adjusted pre-tax profits of Â£643.4m.
Including one-off items, profit before tax from continuing operations was Â£336.1m last year, the LSE said.
A merger with the German stock exchange would create a "group with global aspirations", said Xavier Rolet, the LSE chief executive.
"The boards believe that the potential merger would represent a compelling opportunity for both companies to strengthen each other," the company said.
LSE did not mention a potential rival bid from the owner of the New York Stock Exchange.
On Tuesday, Intercontinental Exchange (ICE), which owns the flagship US stock market, said it was considering making a takeover offer for the LSE.
ICE has until 29 March to make or announce an offer, while Deutsche Boerse has until 22 March.
Under the proposed "merger of equals", the LSE would own 45.6% of the combined group and Deutsche Boerse would hold the remaining 54.4%.
Both companies said all their key businesses would continue to operate under their current brand names.
The merged company would also have dual headquarters in London and Frankfurt.
The London Stock Exchange (LSE) has said a merger with Deutsche Boerse would be "compelling" as the UK firm reported a rise in profits for last year.