AstraZeneca’s chief executive David Brennan has maintained he will be staying in the top role despite speculation surrounding the company’s future.

Last week, some of the drug giant’s shareholders questioned whether Brennan was the man to pull the flailing company out of its pipeline problems. But the pharma head has defended his position during an interview with Bloomberg at the meeting of the Pharmaceutical Research and Manufacturers of America where he said he was “plugged in”.

“I read and hear and see lots of things, but we’re here trying to change policy, make good decisions and execute our strategy… I’m plugged in, my role hasn’t changed a bit,” he said.

“If it’s about restructuring, we can do that without a big deal. Maybe somebody sees something different, but spending more money does not have a linear increase in the number of returns you get from a research and development perspective.”

AstraZeneca will be one of the drug giants that will be hardest hit by patent expiries in the near future including Seroquel and Atacand in 2012, Nexium in 2014/15 and Crestor in 2016. A $15.6 billion acquisition of MedImmune in 2007 has done little to smooth the journey – and according to one shareholder speaking to Reuters this has “tarnished” Brennan’s reputation.

Brennan, 58, has held the top spot for the past six years and has said his strategy moving forward would be a focus on small acquisitions, partnerships and licensing deals, however analysts and investors have questioned whether this strategy will be enough.

While a company spokeswoman has also said Brennan “remains fully committed to leading AstraZeneca” there is speculation the chief will step down around the time of his 60th birthday.