WASHINGTON (AP) — The doctor nominated to head the powerful Food and Drug Administration told senators Wednesday that his first priority would be tackling the opioid crisis, and he pledged that science will prevail at the agency despite his extensive financial ties to medical companies it regulates.

Dr. Scott Gottlieb is a physician-turned-health consultant who has criticized many FDA regulations as unnecessary and has what opponents call unprecedented financial entanglements.

But Gottlieb told a Senate health committee that as a cancer survivor, he knows firsthand the importance of "what the...