But a key Democratic senator wants an investigation of the contract. Sen. Claire McCaskill, also of Missouri, says the no-bid award raises serious questions.
"Was it justified as a no-bid contract?" McCaskill asked in a press conference last week. "Overall, I think we need to begin asking policy questions about the kind of money we're spending developing drugs where the United States is the only customer."
A White House spokesman declined to comment to CNN and instead referred all questions to Health and Human Services.
In a written statement, an HHS spokesman said the contract was awarded "after a rigorous market analysis determined that Siga was the only known company in the world with the capability to produce the required antiviral drug within the required time period."
A smaller drug firm based in Durham, North Carolina -- Chimerix -- had earlier told government auditors that it could develop a similar drug. Chimerix was then given the opportunity to bid for any additional funds beyond the original contract.
HHS also told CNN that the price of the drug was of no concern.
"We can't get into the details, but the final rates ended up well within industry standards," the spokesman said. As for replacing the contract officer, the spokesman said: "This change actually resulted in substantial savings for the U.S. government."
That's something McCaskill questions.
"If the United States government is going to be the only customer, why is it that the stockholders get all the profit if we're the ones putting up a significant portion of the development money when, in fact, the United States becomes the only customer?" she asked.
As for the replacement of the HHS official, Siga said in its e-mail to CNN:
"The findings, the negotiations and the decision to award were handled solely by career procurement officials at HHS who negotiated a fair and reasonable price."
Siga board member Fran Townsend, appearing on CNN's "Anderson Cooper 360" Thursday night, defended the contract process and insisted it followed standard operating procedures.
"I can tell you not Ronald Perelman, not Andy Stern, no member of the (Siga) board was involved in these contract negotiations and never contacted anybody in the government about this contract," said Townsend, who works full time for McAndrews and Forbes, a company owned by Perelman, and who also is CNN national security contributor.
Townsend contended that the contract was put out in a competitive process but "Chimerix ultimately was not competitive in this process."
"It ultimately was ... a sole-source contract ... because there was nobody to compete," Townsend said. "There was nobody (aside from Siga) with an anti-viral that could meet the government's standards."
She added that the government has given a research-and-development grant to Chimerix to encourage competition. "The government has bent over backwards to try and balance the need for an anti-viral against competition," Townsend said.
Townsend also said the claim that Siga's return on investment was 180% was "inaccurate." However, she said the actual rate was confidential.
She pointed out that an FDA advisory committee will be holding a public hearing on the drug on December 14.
Internal HHS documents obtained by CNN also show that as part of the early negotiation process, two key Siga executives granted themselves salary increases of $200,000 in the case of CEO Eric A. Rose and $225,000 for Siga Chief Financial Officer Daniel Luckshire.
According to the internal memo, dated January 14, 2011, Siga "now believes a pending government award merits bonuses for the most highly paid executives."
