For those who may not remember, Peter Rost is the controversial gadfly and former Pfizer exec who is locked in a whistleblower lawsuit with the big drugmaker over his allegations that Genotropin, a human growth hormone, was marketed for unapproved uses, such as combating aging in adults and treating short stature in children. Rost worked for Pharmacia, which was bought by Pfizer.

Although the US Justice Department failed to join his lawsuit, Rost is pressing on and his case is being closely watched. Last year, he cited numerous instances in Indiana and Kentucky in which Genotropin marketing may have violated the False Claims Act. Providing such detail was needed for the case to proceed and his efforts may serve as a template for other whistleblowers who are stymied by federal judges seeking details that are very hard to come by.

Rost showed that is possible to clear rule 9b of the False Claims Act, which refers to fraud claims with “sufficient specificity,” another way of saying a whistleblower must provide very specific info about false claims a drugmaker submitted to the government for payment. This may include amounts charged, drugs prescribed, patient diagnosis and individuals involved in billing, a level of detail that can be very hard to obtain, given patient privacy laws such as HIPAA.

Pfizer has repeatedly moved to dismiss the case, but yesterday the Justice Department filed an amicus brief, stating it “remains a real party interest” in the litigation, even though it chose not to intervene. The reason for its brief was, essentially, to shoot down Pfizer’s interpretation of the Medicaid Act and the False Claims Act. “The United States has a keen interest in the development of the law in this area and in the correct application of the law in this, and similar, cases,” the DOJ writes. In doing so, the government gave Rost a lift, even with a caveat that no position was taken on the merits of his claims (here is the brief).

In explaining its views, the DOJ argues that “summary judgment should not be granted simply because someone other than the defendant submitted the false claims, a prior authorization scheme existed, or physicians deny that they were influenced by kickbacks.” The DOJ also contends that circumstantial evidence is sufficient to prove that the False Claims Act can be violated.

The DOJ rejects several Pfizer arguments. For instance, the DOJ writes that “…the fact that Pharmacia may have caused false claims to be submitted through the actions of pharmacists is irrelevant. As long as the submission of the false claims was the foreseeable result of its illegal kickbacks, it has caused the submission of false claims and is liable under the FCA.”

Pfizer has been arguing that Rost’s lawsuit should be tossed because the drugmaker itself had not submitted any claims to Medicaid that could be construed as false and Genotropin was already listed under state prior authorization programs, among other things.