Mark Cuban on Wednesday condemned a federal agency’s plan to give a pharmaceutical company controlled by a Chinese billionaire exclusive rights to a new liver cancer treatment developed with U.S. government researchers.

The Dallas Mavericks owner, himself a billionaire, told HuffPost the decision “ignored” the need to use taxpayer-funded research in a way that advantages Americans.

“USA inc has got to start operating in the best interests of all of us shareholders,” the “Shark Tank” host wrote in an email, after retweeting a link to a HuffPost report on the licensing plans. “Our taxes should be an investment that expects a financial and social return.”

The National Institutes of Health proposed awarding Salubris Biotherapeutics Inc. exclusive worldwide rights to a portfolio of patents on an antibody drug used to treat liver cancer, according to a notice published Monday in the Federal Register, first reported by HuffPost.

The firm is the Maryland-based arm of Shenzhen Salubris Pharmaceuticals Co., the Chinese drugmaker run by former Shenzhen mayor and billionaire Ye Chenghai, who with his family controls a 66-percent stake in the $5 billion company.

The NIH proposal comes amid growing public backlash against deals that give drugmakers exclusive rights to treatments developed by federally funded researchers without requiring them to sell the drugs to Americans at a reasonable price.

Last week, Sen. Bernie Sanders (I-Vt.) announced legislation that would require federal agencies and federally funded nonprofits, such as research universities, to secure a reasonable pricing agreement from a manufacturer before awarding it exclusive rights to drugs, vaccines or other health care products. Rep. Peter DeFazio (D-Ore.) introduced a companion bill in the House.

Bloomberg via Getty Images Mark Cuban has toyed with a presidential run in 2020.

Sen. Angus King (I-Maine) included a clause in the military spending bill last month directing the Department of Defense to break pricing monopolies when the cost of a taxpayer-funded drug is higher than the median price charged in the seven countries that have at least half the per-capita income of the United States. Rep. Marcy Kaptur (D-Ohio) followed up with a similar amendment in the Department of Health and Human Services spending bill making its way through the House of Representatives.

Cuban, a loud critic of President Donald Trump, is the first business leader and television celebrity to weigh in on the issue.

“You have to do it as a condition of the funding for the research or any tax credits,” Cuban said of preventing price gouging on government-developed drugs. “Once a company has the rights to the drug it’s too late.”

Licensing of taxpayer-funded drugs first entered the national spotlight earlier this year, when Sanders vocally opposed the Defense Department’s plan to give drugmaker Sanofi Pasteur exclusive rights to a Zika vaccine developed by the U.S. Army. The French pharmaceutical giant demanded a monopoly on the vaccine ― used to inoculate against the mosquito-borne and sexually transmitted Zika virus, which causes devastating birth defects ― despite an Army request for a reasonable pricing agreement. The company has a history of charging up to eight times more for its drugs in the U.S. than in France or the United Kingdom.

Monopoly licenses are granted to incentivize manufacturers to make important drugs available, despite the high costs of researching and developing the treatment. The U.S. government agreed to up to $173 million to cover second- and third-phase trials on the vaccine.

Less is known about the Salubris deal, but critics panned the agreement as brazen at a time when lawmakers and watchdog groups are increasing scrutiny of such monopolies.