Gilead Sciences Inc. (GILD) is being asked by U.S. House Democrats to explain how the company set its $84,000 price for hepatitis C treatment Sovaldi. The lawmakers also asked Gilead Chief Executive Officer John Martin to explain what is being done to make sure the medicine gets into the hands of low-income patients, especially in government-run health programs. “Our concern is that a treatment will not cure patients if they cannot afford it,” Democratic representatives Henry Waxman of California, Frank Pallone Jr. of New Jersey, and Diana DeGette of Colorado, wrote in a letter sent yesterday. The lawmakers asked Gilead to brief Congress by April 3. Gilead’s drug was approved last year as a breakthrough treatment for viral liver infection. The medicine offers higher cure rates and fewer side effects than older treatments, and its high cost has attracted scrutiny and resistance from insurers and public health advocates.