Auditors found that researchers did not report the results of animal studies in a drug that was already being tested in humans, a breach that one medical ethicist described as a “mortal sin” in the world of drug research. They also concluded that workers at the research center did not properly monitor clinical trials and paid hospitals in ways that could be seen as bribery.

Last year, Glaxo said, a more favorable audit found the concerns had been addressed. But several outside experts said the problems outlined in the initial audit were grave and painted a picture of an organization that failed to keep tabs on a crucial research center as it expanded both in size and scope. And it indicates that the problems there were more extensive than were reported in June, when the company fired the head of research and development in China after discovering that an article he helped write in the journal Nature Medicine contained misrepresented data.

In a statement, Glaxo said it was committed to conducting “robust” audits of its business practices, and in this instance, “the process worked exactly as intended.” It added, “Patient safety is paramount and the audit reports do not show that this was compromised.”

Glaxo’s research and development center opened in 2007 with lofty ambitions not only to help the company’s drugs get approved in China, but also to serve as one of its primary research hubs. The center grew quickly, expanding from one employee in 2007 to 460 in 2011, according to the audit. But as it grew, supervisors did not always ensure that the work done there was of high quality, auditors found.

One of the most troubling lapses — a problem the report labeled “critical” — involved a drug known as ozanezumab, which was being developed to treat patients with multiple sclerosis and Lou Gehrig’s disease.