NEW YORK (Reuters) - Novartis AG NOVN.S blamed former executives Brian and Allan Kaspar for the manipulation of data behind its $2.1 million gene therapy Zolgensma, saying they either personally manipulated the data or pressured subordinates into doing so.

FILE PHOTO: Logo of Swiss drugmaker Novartis is seen at its branch in Schweizerhalle near Basel, Switzerland, March 29, 2018. REUTERS/Arnd Wiegmann/File Photo

The Kaspar brothers were executives at AveXis, the company that developed the drug and was acquired by Novartis for $8.7 billion last year.

Last month, the U.S. Food and Drug Administration said Novartis could face civil or criminal penalties because of the data manipulation and the possibility the company had waited to notify regulators.

The new allegations were in Novartis’ response to the FDA’s inspection report. They were written by the company in late August and released by the regulator on Tuesday.

After its investigation, Novartis fired AveXis’ Chief Scientific Officer Brian Kaspar and Senior Vice President of Research and Development Allan Kaspar for cause on Aug. 13.

The company also said its internal investigation was drawn out because of the Kaspars’ “lack of cooperation and categorical denial of the allegations.”

“AveXis shamelessly attempts to blame others for its own disclosure decisions to the FDA,” John Hueston, a lawyer for Brian Kaspar, said in a statement. “Dr. Kaspar cooperated with the company investigation. Then and now, Dr. Kaspar has appropriately and categorically denied all wrongdoing.”

Allan Kaspar could not be reached for comment.

The FDA said in August that Novartis had flagged the manipulation to regulators in June, a month after Zolgensma had been approved and several months after a whistleblower told the company about the data manipulation.

In its response to regulators, Novartis also acknowledged that AveXis’s culture of quality was inadequate, and has since created a new data integrity officer position to watch over the reams of information produced by the unit’s activities.

The company has also committed to letting the FDA know within five business days if it receives any credible allegation related to data integrity impacting any of its pending drug applications. It has also hired an outside manufacturing consultant to assess AveXis’ data integrity controls and practices.

Zolgensma - the world’s most expensive drug - was approved as a one-time treatment for spinal muscular atrophy (SMA) in late May.

The disease often leads to paralysis, breathing difficulty and death within months for babies born with the most serious Type I form. SMA affects about one in 10,000 live births, with 50% to 70% having Type I disease and is the leading genetic cause of death in infants.