Pfizer (PFE) reported its biggest quarterly profit in three years as the company reported its best-ever quarter and the blockbuster drug it was selling to treat the disease gained traction.

The stock surged more than 3% to $8.75 per share.

Analysts said the sales boost is partly due to Pfizer’s strategy of offering its products for a lower price tag than its rival Amgen.

Pfizer also increased its cash flow by about $20 billion, which helps offset its $100 billion annual operating cost.

The company has been struggling to stem a decline in the drug revenue and its stock has lost more than a third of its value since the beginning of the year.