Mr. Collins told reporters Thursday that he had done nothing wrong. He described the inquiry as being the result of a “witch hunt” driven by Representative Louise Slaughter, Democrat of New York, who requested the investigation. The office dismissed another allegation — that Mr. Collins purchased discounted stock not available to the public.
Mr. Collins’s involvement with the company surfaced in December of 2015, and picked up steam during the confirmation of Mr. Price, a former Republican Congressman from Georgia whose active investment in pharmaceutical and health care stocks drew scrutiny — and calls for an investigation — from Democrats, including Ms. Slaughter.
In a statement, Ms. Slaughter said, “He put his obsession to enrich himself before the people he swore to represent. It is a disgrace to Congress and to his constituents, who deserve better.”
The congressional ethics office said Mr. Price refused to cooperate with their investigation, as did Simon Wilkinson, Innate’s chief executive, and other company officials and investors. It recommended that the House committee issue subpoenas to those who did not cooperate. Mr. Price and officials with Innate could not be reached for comment.
Mr. Collins enthusiastically pitched Innate to nearly everyone he met, the report said, discussing the company with members of Congress and his own staff, “most” of whom were also investors. “The bigger question would be, who haven’t I talked to?” he told investigators. Two of Mr. Collins’s children also owned stock.
The report found that Mr. Collins frequently updated shareholders on the company’s activity, including nonpublic information, in possible violation of federal law and House rules. Some of the nonpublic information that he shared in emails, the report said, included details about how many participants had enrolled in the company’s crucial clinical trial and details about the company’s communications with large drugmakers who might be interested in acquiring Innate.
The report also found that Mr. Collins may have violated ethics rules in mingling his official and personal roles when interacting with employees at the N.I.H. In 2013, during a public hearing, Mr. Collins mentioned the drug Innate was developing — called MIS416 — without disclosing his financial interest.
His Congressional staff later set up a meeting with N.I.H. staff. Mr. Collins told them that he was associated with Innate and asked one employee — an expert on multiple sclerosis — for assistance with the company’s clinical trial, the report said. That employee later met with Innate’s chief scientific officer three times, the report found.
In comments to reporters, Mr. Collins said it was the N.I.H. that “invited me to go there and this was an afterthought at the end of a tour.” He said the later meetings were a “scientist to scientist” conversation about the frustrations of developing treatments for multiple sclerosis, and nothing more.
Mr. Price divested from Innate as well as other health care stocks after he became the head of H.H.S., but Mr. Collins is still the company’s largest investor. Mr. Price resigned in September from his Cabinet post after facing criticism for his expensive use of charter jets for government trips.
In June, Innate’s stock plummeted by more than 90 percent after it announced that the clinical trial of its drug had failed. Michael A. Quinn, Innate’s chairman said in the company’s annual report that Innate is still reviewing the results of the trial and that the company’s future hinges on the drug’s success.
A photograph with an earlier version of this article was published in error. The photograph was of Representative Doug Collins of Georgia, not Representative Chris Collins of New York, as the picture caption incorrectly noted.