Nigerian families can sue Pfizer in U.S. courts with claims that the giant drug maker violated international law banning involuntary medical experimentation on humans when it tested an antibiotic to treat meningitis, an appeals court ruled Friday.

The 2nd U.S. Circuit Court of Appeals overturned rulings by a lower court judge who had tossed out the lawsuits in litigation that began in 2001.

The lawsuits sought unspecified damages on behalf of children and infants who were part of a 1996 study of the oral antibiotic Trovan. The testing occurred during a meningitis epidemic that killed more than 15,000 Africans.

The lawsuits claimed Pfizer violated international law, federal regulations and medical ethics by rushing to test the experimental antibiotic without their consent or knowledge - an assertion Pfizer denies.

Pfizer said it "remains confident that it will prevail in these cases, and is weighing its options on how to best respond to this decision."

Peter Safirstein, a plaintiffs' lawyer who argued the appeal, called the ruling "very, very important."

The lawsuits were dismissed on grounds they could not be pursued under the Alien Tort Statute, an 18th century law that allows foreigners to sue in U.S. courts over international law violations.

The appeals panel ruled 2-to-1 Friday that the statute can be used.

It cited international law banning the nonconsensual medical experimentation on humans that was established with the war crimes trials at Nuremberg, where 15 doctors were convicted of war crimes and crimes against humanity for conducting medical experiments without consent. Seven of the doctors were sentenced to death and eight were sent to prison.

In 1996, Pfizer sent three American physicians to work with four Nigerian doctors to experiment with Trovan on children who were hospital patients in Kano, Nigeria.

The lawsuits say the two-week experiment on 200 sick children led to 11 deaths and left many others blind, paralyzed or brain-damaged.

The plaintiffs said Pfizer, working with the Nigerian government, failed to secure the informed consent of either the children or their guardians and failed to disclose or explain the experimental nature of the study or the serious risks involved.

In its statement, Pfizer said the 1996 clinical study was conducted with the approval of the Nigerian government and consent of the participants' parents or guardians and was consistent with both international and Nigerian laws.

"Pfizer has great sympathy for everyone who suffered during the devastating meningitis epidemic in 1996," it said. "The company has said all along that all clinical evidence points to the fact that any deaths or injuries were the direct result of the illness, and not the treatment provided to patients in the Pfizer study."

The company said Trovan helped save lives with a survival rate of 94.4 percent, compared to a survival rate of slightly less than 90 percent for those who did not participate in the study.

In ruling, the appeals court said pharmaceutical companies had greatly increased the number of drug trials in poor countries in the last two decades, allowing life saving drugs to be developed faster and at less cost while providing developing countries with cutting edge medicines and treatments.

However, it said large-scale drug trials without informed consent "threatens these efforts because such conduct fosters distrust and resistance to international drug trials, cutting edge medical innovation and critical international public health initiatives in which pharmaceutical companies play a key role."