* Pan-European STOXX 600 index little changed
* Stada soars to new record after "generous" offer
* Hedge fund plan to unlock value in BPH boosts stock
* Barclays slips after whistleblowing probe hits CEO (Adds details, updates prices)
By Danilo Masoni
MILAN, April 10 (Reuters) - Gains in mining giant BHP Billiton and fresh merger and acquisition activity in the pharmaceutical sector led otherwise flat markets in Europe on Monday.
The pan-European STOXX 600 index and Britain's FTSE 100 were little changed, while Germany's DAX inched 0.05 percent lower.
European shares joined a global stock market rally at the end of last year on growing optimism over the economic outlook but caution has stepped in over the past few weeks as the first-quarter earning seasons approaches and doubts over a fiscal stimulus in the United States have emerged.
"Markets continue to struggle to break out from of their main ranges," said Alessandro Balsotti, fund manager at JCI Capital in Milan. "In the last two sessions potential political, monetary and economic triggers were not missing but the effect on the various asset classes hasn't been significant."
The STOXX has gained just 0.1 percent over the past seven sessions - a significant slowdown since the sharp gains it saw after the election of U.S. President Donald Trump.
On Wednesday, German drugmaker Stada soared 11 percent, leading gainers on the STOXX index and hitting a fresh record high. The company said it had decided to support an offer from Bain Capital and Cinven for 66 euros per share, valuing the company at about 5.32 billion euros.
"We believe this is very generous to Stada's shareholders and recommend they accept the offer," James Vane-Tempest, equity analyst at Jefferies, said in a note.
Fresenius inched up 0.2 percent after saying it was in talks with the generic drugmaker Akorn for a potential takeover.
While Fresenius said there could be no assurance that a deal would result from the talks, one trader in Frankfurt said a key question was how would the group eventually pay for the possible acquisition. "Capital hike or not?," he said.
BHP Billiton rose 4.8 percent, leading a positive mining sector, after hedge fund manager Elliott Advisors put forward a proposal to unlock value from the mining giant.
Eliott sent a plan to BHP directors to unlock shareholder value by scrapping the miner's London Stock Exchange listing, demerging its U.S. oil arm and revising its capital return policy.
Gains among miners and pharma were offset by weaker energy stocks and financials.
In the financial sector, Barclays fell 0.2 percent after news that British regulators were investigating the bank and its CEO, Jes Staley, over the handling of a whistleblowing incident. (Reporting by Danilo Masoni; Editing by Andrew Heavens)