The Nigerian government filed criminal charges against the firm last month and is seeking $7bn (€5.2bn) in damages.
The world's top dog pharma firm attempted to have the case thrown out of court yesterday, arguing that 85 amendment claims that had been made to the original 54 claims cited in the case, had been improperly filed.
While the judge agreed that the new claims were indeed improperly filed and rejected them, he refused to dismiss the case and set the next hearing for July 20.
Pfizer failed to return a call asking for comment on the matter.
Five civil claims for damages totalling $2bn are also reported to have been filed against Pfizer, and seven of its employees involved in the trials, by the attorney general of Kano, in northern Nigeria, whre the trials took place.
Pfizer vehemently denies the allegations of misconduct surrounding the drug trials, which took place in 1996, and the dispute is not new - Nigeria and Pfizer have been tussling over the matter for years.
The drug at the centre of the furore, Trovan (trovafloxacin), was at the time a late-stage experimental antibiotic treatment for meningococcal meningitis.
It was allegedly given to around 100 children in Kano after the area suffered a large meningitis outbreak.
Prior to this, the drug had already been tested in 5,000 patients elsewhere, said Pfizer.
However, according to the Washington Post, the drug had never before been tested in children with meningitis and Nigerian officials are claiming in the lawsuit that Pfizer's actions resulted in "the deaths of an unspecified number of children and left others deaf, paralyzed, blind or brain-damaged".
"Every surviving child suffered one or more disabilities, the lawsuit says, adding that the state of Kano has incurred major costs caring for the children and otherwise dealing with the drug trial's repercussions".
In addition, the lawsuit claims that researchers did not obtain consent from the children's families, that parents were banned from the ward where the drug trial occurred, and that the researchers knew Trovan had potentially life-threatening side effects, according to the Washington Post.
Furthermore, it is alleged in the court documents that researchers administered the comparison drug in the trial, Hoffmann-La Roche's Rocephin (ceftriaxone), to around 100 children in "dangerously low doses to make Trovan look more effective", and after the completion of the trial, Pfizer took all medical records and "obliterated any evidence".
The Washington Post also said it had obtained internal Pfizer records showing that five children died after being treated with the Trovan, although there is no indication in the documents that the drug was responsible for the deaths and that six children also died while taking Rocephin.
According to the newspaper, in 2000 Nigeria's health minister appointed a panel of experts to look into the trial, and an ensuing report concluded that Pfizer's actions violated Nigerian law, the international Declaration of Helsinki and the UN Convention on the Rights of the Child.
It also said there were no records documenting that Pfizer told the children or their parents that they were part of a drug trial, nor were they told that alternative treatments were available.
In addition, it said an approval letter from a Nigerian ethics committee, which Pfizer used to justify its actions, was a branded as a "sham concocted long after the trial ended".
Nigeria subsequently brought a previous lawsuit against Pfizer in a US court although this was dismissed in 2005 by a federal judge who said the case should instead be heard by a Nigerian court, which this latest lawsuit will be.
In response to the fresh legal challenge, Pfizer issued the following statement last month: "…the 1996 Trovan clinical study was conducted with the full knowledge of the Nigerian government and in a responsible and ethical way consistent with the company's abiding commitment to patient safety.
Any allegations in these lawsuits to the contrary are simply untrue - they weren't valid when they were first raised years ago and they're not valid today."
"The Trovan study introduced a new meningitis treatment to the region that indisputably helped save the lives of almost 200 children stricken with meningococcal meningitis, a disease that if left untreated, kills four out of every 10 people who contract it."
Pfizer also said that at the time of the meningitis outbreak in Kano its doctors had "solid scientific evidence that it
[Trovan] would provide a safe and effective treatment" against meningitis.
"At a 94.4 per cent survival rate, Trovan performed at least as well as the best treatment available."
Incidently, the drug is not available in Europe and is only available in the US for adults, although its use is restricted due to its reported association with liver toxicity and deaths.
The case highlights the potential minefield pharmaceutical companies are entering as they increasingly conduct drug testing in the developing world, especially in regard to informed consent.