Three employees of US drug giant Pfizer appeared in court Monday facing criminal charges filed by the Kano state government over an allegedly illegal 1996 meningitis drug trial.
The judge adjourned the case until March 4 when Pfizer's challenge to the court's legal jurisdiction will be heard.
Pfizer employees Bashir Bello, Segun Dogunro and Lere Baale stood in the witness box for the first time since civil and criminal proceedings were launched against the drug firm and eight of its staff eight months ago.
The accused face 65-charge counts of criminal conspiracy, causing grievous harm and culpable homicide.
The Kano state government filed civil and criminal suits demanding 2.75 billion dollars (two billion euros) in compensation from Pfizer and prosecution of its staff involved in testing Trovan during a triple epidemic of measles, cholera and meningitis in which over 12,000 people died.
The drug test allegedly led to 11 deaths and deformities in 189 other cases such as blindness, deafness, brain damage and paralysis.
Pfizer denies any wrongdoing and insists that the trial was conducted with the approval of the Nigerian government and conformed to ethical procedures.
The presiding judge Shehu Atiku issued a summons Monday for the managing director of Neimeth Pharmaceuticals, an off-shoot of Pfizer to appear before it to answer the same charges.
Sam Ohabunwa was managing director of Pfizer Nigeria when the illegal trial was alleged to have taken place.
Three US-based Pfizer staff also accused of involvement have not made an appearance but the prosecution said it had submitted extradition requests to the Nigerian justice minister.