According to new legal docs obtained by TMZ ... Madonna just lost her appeal to slam the brakes on the sale of the letter. A New York State Appeals Court ruled Madonna can't pursue claims against Darlene Lutz, her old pal and art consultant, or GottaHaveRockandRoll.com -- the online auction house to which Lutz consigned the items for sale.
Tuesday's court ruling opens the door for the sale of some of Madonna's intimate personal items, including the breakup note from her ex-boyfriend, Tupac.
The appellate court upheld the judge's ruling in a 5-0 decision, saying Madonna's claims are blocked by the "very broad" release.
We reached out to Madonna's reps for comment ... so far, no word back.