Pfizer (PFE) sought to allay fears that its proposed $106 billion takeover of AstraZeneca (AZN.L) would deal a blow to drug research, saying the new company would bolster innovative science and speed the development of new treatments. AstraZeneca, Britain’s second-largest drugs company, has rejected successive approaches from its larger American rival. As political opposition to the plan grew, Pfizer reiterated its commitment to the deal, posting a graphic on its website that touted the benefits of a merger.