Several U.S. drugmakers are being investigated for nonprofit contributions to help patients pay out-of-pocket drug costs.

United Therapeutics Corp (UTHR - Get Report) set aside $210 million for a possible settlement with the Department of Justice regarding an investigation into the drugmaker's contributions to patient-assistance charity groups, the Wall Street Journal reported.

The Justice Department is investigating whether the contributions violate federal laws against kickbacks and false claims. A United Therapeutics filing with the Securities and Exchange Commission shows the Silver Spring, Md.-based company is in settlement talks to resolve the investigation, but thinks it could successfully defend itself against any Justice Department action.

United Therapeutics is one of several companies, along with Johnson & Johnson (JNJ - Get Report) , Pfizer (PFE - Get Report) and Biogen (BIIB - Get Report) , under investigation for nonprofit contributions to help patients pay out-of-pocket drug costs. United Therapeutics is the first company to disclose a potential settlement.

United Therapeutics stock traded down over 2% Thursday morning.

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