Moderna Inc.'s chief executive Wednesday defended the company's plan to quadruple the price of its COVID-19 vaccine, telling U.S. lawmakers it will no longer have the economies of scale from government procurement when the shots move into the private market.

Moderna CEO Stephane Bancel was called to testify after the company's announcement that it planned to raise the vaccine's price to around $130 per dose drew the ire of lawmakers, especially Democratic U.S. Senator Bernie Sanders, who chairs the influential Committee on Health, Education, Labor and Pensions and has long demanded lower U.S. drug prices.

Bancel said the company will have to provide single-dose vials or pre-filled syringes of its COVID vaccine when it moves into the commercial market, compared to filling 10 dose vials for government procurement.

"On top of all this, we're expecting a 90% reduction in demand," Bancel said. "As you can see, we're losing economies of scale."

Sanders wrote to Bancel in January asking Moderna to halt its planned U.S. price increase for the COVID shot, saying the price hikes could make it unaffordable for millions of Americans, and noting federal financial assistance in developing the vaccine.