Those are the contentions of attorneys suing the company who Wednesday released dozens of documents that had previously been under court seal.
Houston attorney Ed Blizzard said the documents "show that Seroquel was not effective and had serious risks."
"AstraZeneca knew those facts but spun, skewed and concealed that data from doctors, patients, and sometimes their own scientific investigators," Blizzard contended.
The first case of about 15,000 patients who are suing AstraZeneca -- most claiming Seroquel led to diabetes -- is expected to go to trial next month. AstraZeneca will also go before the U.S. Food and Drug Administration next month to seek approval for Seroquel use among children and adolescents.
But attorneys suing AstraZeneca suggested this week that documents showed the company knew much more about Seroquel -- approved for schizophrenia and bipolar disorder in adults -- than it told the public.
Attorneys say, for instance, that the company promoted Seroquel as "weight neutral" despite a study that showed significant weight gain after 18 months on the drug.
In a 2001 e-mail, then AstraZeneca psychiatrist John Travers said, "These data also suggest to me that the concept of "weight neutrality" are not supported by these data." He argued that presentations should include the data.
Another e-mail discussed "trial 41," which the liability attorneys say showed an extended-release version of Seroquel was no better than a placebo.
"We are under clear instruction from the highest level within AstraZeneca at this time not to discuss details surrounding trial 41 with any external customers," Simon Hagger, then AstraZeneca's global brand manager for Seroquel, wrote in the e-mail.
AstraZeneca spokesman Tony Jewell Wednesday accused the lawyers of attempting to try the case in the media and notes the first two cases were dismissed for lack of evidence.
"AstraZeneca conducted 118 studies (on Seroquel)," Jewell told ABC News. "We shared all of the required data with the FDA both before and after it was approved. We stand by our clinical research."
FDA spokeswoman Sandy Walsh said in an e-mail today that Seroquel's label has been updated as new information dictates, and that AstraZeneca has never resisted any of those efforts.
"The Seroquel label from the very first approval reflected metabolic side effects, and that language has been strengthened over the years as new data became available," she said. "Like all other atypical anti-psychotic drugs, Seroquel got a very strong Warning statement about potential diabetes in 2004."
"It is important to distinguish between what is said in internal company documents reflecting internal disagreements about how to present and characterize certain findings and what a company actually provides to FDA," Walsh said. "There is no evidence that at any point AstraZeneca withheld important data from the FDA. If there was such evidence, that would be important, but we are not aware there is such evidence."
Some in the medical community are skeptical about the release of the internal AstraZeneca documents.