Pfizer has parted ways with Peter Rost, its not-so-favorite whistle-blower.

The company, the world’s largest drug maker, said yesterday that it had fired Mr. Rost, a vice president for corporate marketing who engaged in a public campaign against Pfizer over drug prices for the last year.

His dismissal came after a federal judge in Boston unsealed a lawsuit Mr. Rost filed in June 2003 against Pfizer, asserting that Pharmacia, a drug maker Pfizer bought in April 2003, illegally promoted the sale of human growth hormone for unauthorized uses.

Mr. Rost contends that Pharmacia offered doctors illegal inducements to use genotropin, its growth hormone, as an anti-aging drug for adults. The Food and Drug Administration has not approved human growth hormone for that purpose, and drug makers are not supposed to promote their products for purposes that have not received approval.

The fact that the suit was unsealed is actually a positive development for Pfizer, because it indicates that the government has chosen not to participate in the suit alongside Mr. Rost. Whistle-blower lawsuits typically remain secret when the government participates.