KANO, Nigeria (AP) - A judge on Wednesday cleared prosecutors to serve court summons to Pfizer's retired chief executive and other officials named in a case alleging that a drug experiment by the pharmaceutical giant led to deaths and disabilities among children.

Pfizer officials, including retired CEO William Steere, are named in cases filed by officials in the northern Nigerian state of Kano stemming from a trial of a meningitis drug that Nigerian prosecutors say injured young subjects.

A separate federal criminal case and two civil cases - one filed by federal authorities, the other by state authorities - also were pending.

A judge in Kano, the city with the same name as the state where the study was conducted in 1996, allowed for papers to be served to the Pfizer staff in the criminal case.

Prosecutors said that would compel the defendants to attend the next hearing in the state criminal case, which was scheduled for Nov. 6.

Prosecutors say the defendants were criminally negligent, among other charges. If convicted the defendants could face at least seven years in prison. Pfizer denies all the allegations.

A judge hearing the federal civil case also ruled that Steere and others may be served notice that they should appear in court for those hearings. That case, filed by the federal government and under deliberation in the capital Abuja, was adjourned till Oct. 22.

Pfizer said Wednesday after the proceedings it had not been summoned before in any criminal cases.

"Neither the company nor any of the individuals have been served with criminal papers in this case," said a Pfizer spokesman, Christopher Loder, from New York.

Steere was Pfizer Inc.'s chief executive between 1991 and 2001, the period during which the test was carried out.

Pfizer, in a statement, reiterated its position that "it acted ethically in carrying out the 1996 clinical investigation of the efficacy of its drug, Trovan".

New York-based Pfizer Inc. treated 100 meningitis-infected children with an experimental antibiotic, Trovan, in a 1996 study. Another 100 children, who were control patients, received an approved antibiotic, though families' lawyers have claimed the dose was lower than recommended.

The government has charged that the company conducted the study without the full knowledge of parents or proper regulatory approval.

Eleven children died - five of those on Trovan and six in the control group, while others suffered physical disabilities and brain damage.

Pfizer has insisted its records show none of the deaths was linked to Trovan or substandard treatment, noting that the study showed a better survival rate for the patients on Trovan than those on the standard drug, and that mental damage and other serious disabilities are known aftereffects of meningitis.

Authorities in Kano state have blamed the Pfizer affair for widespread suspicion of government public health policies.

Islamic leaders in largely Muslim Kano had seized on the Pfizer controversy as evidence of a U.S.-led conspiracy.
Baseless rumors that polio vaccines spread AIDS or infertility spurred Kano and another heavily Muslim state, Zamfara, to boycott a polio vaccination campaign four years ago.

Vaccination programs restarted in Nigeria in 2004, after an 11-month boycott. But the delay set back global eradication. The boycott was blamed for causing an outbreak that spread the disease across Africa and into the Middle East.