James Biden told the Integrate executives that he would get the Biden Cancer Initiative to promote an oral rinse made by the firm and used by cancer patients, Frey, who said he participated in the call, told POLITICO. He added that James Biden directly invoked the former vice president on the call. "He said his brother would be very excited about this product,” Frey said.

A spokesman for James Biden disputed Frey’s account. “These charges stem from a frivolous lawsuit and are pure fantasy. We are not surprised that such baseless accusations have emerged during the Democratic primaries,” said David Fuscus, a spokesman for James Biden and Platinum Global Partners. “Jim Biden has been clear and consistent that he does not, and has never, discussed his business ventures with his brother.”

A spokesman for the Biden campaign, Andrew Bates, referred questions to Brian Smith, a lawyer at Covington and Burling. Smith said that the cancer initiative closed in July but that he was not immediately able to offer further comment.

Diverse Medical Management is suing James Biden and his partners in Tennessee, alleging they disingenuously offered to invest in the firm as part of a fraudulent scheme to drive it into bankruptcy and steal its business model.

In a separate, previously unreported, lawsuit, Integrate is suing James Biden’s business partners in Palm Beach County, Florida, alleging a breach of contract for failing to follow through on an agreement to invest $3 million in the firm. The suit was filed in June against Platinum Global Partners, a Florida investment firm that has worked with James Biden in recent years on healthcare-related ventures. A lawyer for Integrate, Paul Thanasides, declined to comment.

The original complaint does not mention James Biden or the cancer initiative, but, earlier this month, Integrate filed a request for document production that included “All documents or correspondence regarding the Biden Cancer Initiative, its products or business, relating to, referencing, or regarding Integrate.”

Platinum has sought to have the case dismissed. The firm is represented by Faegre Baker Daniels, which has also represented James and Hunter Biden in a variety of matters. Lawyers at the firm did not offer responses to emailed questions.

In the Tennessee case, Frey’s side has filed sworn declarations alleging that James Biden promised to have his powerful brother help it land business and incorporate its rural healthcare model into his presidential campaign. David Fuscus of Xenophon Strategies, a spokesman for James Biden and his associates, has called those allegations “pure fiction.”

James Biden’s side has also denied engaging in any fraud scheme and said the plaintiffs in the Tennessee case have failed to repay loans made by the defendants. Platinum Group USA, an entity related to Platinum Global Partners, is a defendant in that case.

The Biden Cancer Initiative was a private foundation launched by Joe Biden and his wife, Dr. Jill Biden, in 2017. It was conceived as an extension of the Obama administration's Cancer Moonshot, a program overseen by Biden during the final year of his vice presidency that aimed to develop cancer treatments.

Ahead of the April launch of Biden’s presidential campaign, the former vice president and his wife stepped down from the board of the cancer initiative, before it closed this summer. There appears to be no public indication of James Biden having any involvement with the initiative.

Last month, Joe Biden told POLITICO that, if elected, he would maintain a firewall between his relatives’ business dealings and his administration. "I have never discussed, with my son or my brother or with anyone else, anything having to do with their businesses. Period," he said. "And what I will do is the same thing we did in our administration. There will be an absolute wall between personal and private [business interests] and the government."