The head of the influential trade association for drug manufacturers announced Thursday night that he is leaving his job.

The development comes amid uncertainty over the fate of President Barack Obama's health care overhaul, which the drug association had backed after striking a deal with the White House and Senate Democrats to limit costs to the industry in the legislation.

The deal became very controversial after it was announced last year. The White House had sought to keep specifics of the deal private, but some were disclosed by Billy Tauzin, the president and chief executive of the Pharmaceutical Research and Manufacturers of America, in an apparent effort to ensure they were maintained.

Tauzin said Thursday that he will step down June 30.

Under last year's agreement, costs to the drug industry in the health overhaul legislation would have been limited to $80 billion over 10 years, much of that coming from helping close a prescription drug coverage gap in Medicare, the health insurance program for seniors.

PhRMA was spending more than $100 million on TV ads in support of the health overhaul. But liberal lawmakers, particularly in the House, wanted the drug industry to pay much more in the legislation.

The House version of the bill would have laid billions more in costs on the industry.

The legislation now stands in limbo because of the upset election last month of a Republican to a Massachusetts Senate seat which deprived Democrats of the filibuster-proof supermajority they need to move forward in the Senate.

Tauzin, 66, a former congressman from Louisiana and a cancer survivor, said in a statement Thursday that when he steps down in the summer he will have completed the 5 1/2 years of service he agreed to when he took the job.

He said he will continue to serve as a consultant for PhRMA.

"As the first ever cancer patient to lead PhRMA as its CEO, I now believe it is time I move on and hand the mantle of leadership of this great organization to others as passionate as myself, and to explore the many other interests I would like to pursue in this special second-chance life that I have been given," he said.

"My health is excellent and I look forward to exciting new challenges ahead."

Tauzin was elected to the House as a Democrat in 1980 but switched parties, becoming a Republican in 1995.

He rose to become chairman of the House Energy and Commerce Committee before announcing his retirement from the House in 2004 when suffering health problems.