(Corrects length of Vigodman's tenure in lead to 3 years)
* Erez Vigodman to step down immediately
* Shares have slumped in wake of patent setbacks, acquisitions
* Investors call for major changes in the company
By Tova Cohen and Bill Berkrot
TEL AVIV/NEW YORK, Feb 7 (Reuters) - The chief executive of Teva Pharmaceutical Industries, the world's biggest maker of generic drugs, stepped down after three years following a series of strategic stumbles and legal and operational setbacks that sent its shares plummeting.
Teva, Israel's largest company, said on Monday Chief Executive Erez Vigodman was stepping down immediately and would be replaced on an interim basis by Chairman Yitzhak Peterburg.
A string of questionable and costly acquisitions, along with delayed drug launches, has prompted calls for a management overhaul to lead sweeping structural changes - such as a spin off of its branded drugs businesses and an increased pipeline - to restore investor confidence.
Teva shares, which hit $72 in July 2015, tumbled to a 10-year low of $32.20 last week on the New York Stock Exchange after a U.S. court found patents invalid on Teva's most important branded product, multiple sclerosis treatment Copaxone. The drug accounted for almost a fifth of Teva's revenue last year.
The shares fell more than 2 percent in extended trading after Vigodman's departure, which comes after the head of its generics drugs division, Siggi Olafsson, left the company.
Erez Vigodman joined Teva in 2014 after rejuvenating an ailing Israeli agrochemical firm earned him a reputation as a turnaround specialist and dealmaker.
But a series of stumbles have had investors calling for a shakeup at Teva.
Vigodman embarked on a costly buying spree that culminated in last year's acquisition of the Actavis generics drug business for $40.5 billion - a price investors said was too high.
A $2.3 billion deal for Mexican drugmaker Rimsa has led to both sides suing each other. Teva also paid $144 million to get a migraine patch called Zecuity, but had to pull the product in 2016 after reports that patients were being scarred or burned.
In December it agreed to pay more than $519 million to settle U.S. criminal and civil allegations that the company bribed overseas officials to gain business for its medicines.
Last month Teva provided a 2017 revenue and profit forecast below Wall Street's estimates.
Peterburg said he will conduct a thorough review of Teva's business while the company searches for a permanent CEO. Former Celgene Corp CEO Sol Barer will serve as Teva's new chairman.
RBC Capital Markets analyst Randall Stanicky said it is unclear what this entails and whether asset sales could be a part of this.
Some investors have told Reuters they would like to see Teva spin off its specialty drug business.
"We find it interesting that Teva would pursue a review before naming a permanent CEO, which may be suggestive of further close involvement of the board and broader management team," Stanicky said.
This will be a consideration for any incoming CEO, he added.
Bernstein analyst Ronny Gal, in a video released to clients,
called Peterburg "a good caretaker CEO, but clearly not a candidate to run the company long term."
Prior to rejoining Teva's board of directors in 2012, Peterburg led the company's research and development efforts as head of global branded products, from 2010 until October 2011. (Additional reporting by Steven Scheer, editing by Louise Heavens)