Harvard Law School professor Elizabeth Warren has again outraised Senator Scott Brown in the race for Massachusetts’ junior U.S. Senate seat, raising $3.7 million to Brown’s $2.3 million since July, Federal Election Commission filings show.

This latest infusion of cash brings Warren's race total to a staggering $27.7 million, a figure larger than that of any other congressional campaign in the country. Brown’s own pace—$20.9 million raised since last autumn—is second only his Democratic opponent nationally.

The contest between Brown and Warren has garnered much national attention and triggered an influx of out-of-state cash as both parties fight for the contested Senate seat.

The FEC filings come just a week before Massachusetts’ Sept. 6 primary, when both Brown and Warren will run unopposed and officially win their respective places on the November ballot.

The campaigns have not been shy thus far in putting their money to use. Both Warren and Brown have already spent roughly $15.7 million each on political consultants and advertisements. Brown, who came into the campaign with a reserve of cash left over from his 2010 special election campaign, still has $14.1 million cash on hand, slightly more than Warren's $12.3 million.

Both campaigns signed a pact in January pledging to block third-party spending in the race.

A recent report by the liberal organization Public Policy Polling showed Brown ahead of Warren by five points, leading 49 percent to 44 percent.

—Staff writer Nicholas P. Fandos can be reached at nicholasfandos@college.harvard.edu.