In California's Senate race, Republican Carly Fiorina has bolted out in front of her challengers as the June 8 primary draws near, according to a new poll released Sunday. 

Fiorina has built a 15-point lead over her main primary opponent Tom Campbell -- up 38 percent to 23 percent, in a new Los Angeles Times/USC poll today. 

Campbell, who held a slight lead over Fiorina back in March, is the only Republican who was set up to beat three-term incumbent Sen. Barbara BoxerBarbara BoxerCarly Fiorina 'certainly looking at' Virginia Senate run Top Obama adviser signs with Hollywood talent agency: report 
Democrats vie for chance to take on Trump as California governor MORE (D). Campbell has held a 45 percent to 38 percent lead over Boxer, whereas Fiorina was behind by six points. Another Republican, Chuck DeVore has about 16 percent of the vote and is projected to lose to Boxer by 10 points, according to the poll. 

Boxer is running in a tight race and President Barack ObamaBarack ObamaLongtime diplomat criticizes isolationism in retirement speech Manchin: Sanders backers should challenge me in Dem primary DNC chair vote: live coverage MORE has recently made a couple of fundraising trips out to California to aid her campaign.