UPDATE 4-U.S. FDA chief tough on e-cigs steps down in surprise resignation

(Corrects 13th paragraph to show ban on flavored e-cigarettes and age verification are proposals not yet in effect)

By Yasmeen Abutaleb

WASHINGTON, March 5 (Reuters) - U.S. Food and Drug Administration Commissioner Scott Gottlieb said on Tuesday that he plans to step down next month, a sudden resignation that calls into question how the agency will handle issues such as surging e-cigarette use among teens and efforts to increase competition in prescription drugs.

Gottlieb was well regarded by public health advocates and won bipartisan support for his efforts to curb use of flavored e-cigarettes by youths, speed approval times for cheap generic medicines to increase competition and bring down drug prices, and boost the use of cheaper versions of expensive biotech medicines called biosimilars.

Unlike his predecessors, who said drug pricing was not the purview of the FDA, Gottlieb waded into the intensifying debate about the high cost of medicines for U.S. consumers and had the agency actively looking into possible solutions.

"Scott's leadership inspired historic results from the FDA team, which delivered record approvals of both innovative treatments and affordable generic drugs, while advancing important policies to confront opioid addiction, tobacco and youth e-cigarette use," Health and Human Services (HHS) Secretary Alex Azar said in a statement.

Gottlieb, who said he wanted to spend more time with his wife and three young children in Connecticut, was nominated by President Donald Trump in part to aid in Trump's anti-regulation agenda. But Gottlieb took an aggressive stance toward e-cigarette makers, such as Juul Labs Inc.

On Monday, he confronted 15 retailers including Walgreens Boots Alliance, Kroger Co and Walmart Inc , for illegally selling tobacco products to children. In early February, the FDA pursued enforcement actions against some Walgreen and Circle K locations.

But Gottlieb ran into fierce opposition from anti-regulation groups, such as Americans for Tax Reform, and former FDA officials, who said the agency's regulatory efforts would destroy thousands of jobs.

A coalition of these groups wrote Trump last month asking him to "immediately halt the Food and Drug Administration's aggressive regulatory assault" on e-cigarette businesses.

Following news of Gottlieb's resignation, the Nasdaq Biotechnology Index turned negative.

It closed down 0.5 percent as shares of Amgen Inc erased gains and Gilead Sciences Inc shares fell further. Shares of British American Tobacco Plc rose after the news on Gottlieb, who had signaled his intention to also go after menthol and other flavored cigarette products.