"We do not plan any additional work with Lil Wayne moving forward," a Mountain Dew representative told United Press International in a statement. "His offensive reference to a revered civil rights icon does not reflect the values of our brand."
The brand, owned by PepsiCo Inc., had no further comment. UPI attempts to reach representatives of Wayne and his record label were not immediately successful.
Wayne was a major Mountain Dew spokesman, appearing in several commercials since early 2012.
Wayne's offensive lyric refers to Emmett Till, a 14-year-old African-American brutally killed in Mississippi in 1955. Wayne mentions Till in his verse on the remix to Atlanta rapper Future's 2013 single "Karate Chop."
The insulting line says, "Beat that [vulgar word for coward or weakling] up like Emmett Till."
Till, from Chicago, was killed in Money, Miss., Aug. 28, 1955, by two white men who thought he had flirted with a white woman. The 21-year-old woman's husband and half-brother took Till from his great-uncle's home, where he had been visiting, and brought him to a barn where they beat him and gouged out one of his eyes before shooting him through the head and disposing of his body in the Tallahatchie River, weighting it with a 70-pound cotton gin fan tied around his neck with barbed wire.
His body was retrieved from the river three days later.
Roy Bryant and J.W. Milam acknowledged they killed Till but only after they were acquitted by an all-white jury in a kidnapping murder trial.
Till was returned to Chicago and his mother, who had raised him mostly by herself, insisted on a public funeral service with an open casket to show the world the brutality of the killing.
Till's family said this week it was deeply offended by Wayne's lyric.
Wayne responded with a letter, saying, "It has come to my attention that lyrics from my contribution to a fellow artist's song has deeply offended your family.
"As a father myself, I cannot imagine the pain that your family has had to endure," he wrote. "I would like to take a moment to acknowledge your hurt, as well as the letter you sent to me via your attorneys."
He said he would no longer refer to Till or the Till family in his music.
Till's family said they were still offended because Wayne didn't apologize.
Till cousin and family spokeswoman Airicka Gordon-Taylor said on the Mamie Till Mobley Memorial Foundation Facebook page Wayne's letter "falls short of an apology, as none is mentioned."
Epic Records, Wayne's label, apologized for the lyric and made efforts to take the song down from websites.
The Rev. Al Sharpton, an MSNBC host and president of the National Action Network, said the episode has been a "teaching moment for Lil Wayne, corporate America and the family of Emmett Till, yet more than a condemnation of any one artist, it is an affirmation of Emmett Till and a call for more sensitivity about what we say and do in our culture."
"National Action Network does not want it to end with artists losing contracts but rather with a sensitizing of corporate America so we can learn from these experiences and set a tone that will help everybody."
Sharpton said he planned to meet next week with "leadership at PepsiCo and the family of Emmett Till."