Jones Day has sued a former pharmaceutical corporate client for allegedly not paying $5.3 million in legal fees, asking a court to pierce the corporate veil and force two executives to pay out of their own pockets.

The suit, filed in Manhattan Supreme Court, is unusual both for the amount being sought and the law firm's request to hold Serenity Pharmaceuticals' CEO Samuel Herschkowitz and president Alain Kodsi personally liable.

Jones Day claims that it represented Serenity and several affiliated companies in two drawn-out patent suits brought by competitor Ferring Pharmaceuticals. The firm said it withdrew earlier this year for nonpayment.

Jones Day said Serenity had been a client of James Sottile, a partner who came to the firm from Zuckerman Spaeder in 2016 and left last year for an in-house role at Scientific Games. The work Jones Day did for Serenity in the two cases brought by Ferring in 2012 and 2017 had their ups and downs, but regardless of the result, Serenity had to pay, according to Jones Day's complaint.

The law firm said whenever it brought up payment with Serenity executives, they highlighted the fact that Avadel Specialty Pharmaceuticals, a key patent licensee, had gone bankrupt, and "repeatedly represented that [Serenity] would pay the unpaid bills after it found a new commercial partner who would be willing to provide a sufficient up-front payment." But Jones Day said it shouldn't have to wait.

"Upon information and belief, Serenity received more than $100 million from its previous commercial partners, Allergan and Avadel," the firm said, referring to two pharmaceutical companies. "Still, Serenity has repeatedly represented to Jones Day that it does not have the funds to pay the firm the amounts due and owing to it."

The firm said Herschkowitz and Kodsi "exercised complete domination and control over the operations of Serenity" and commingled their personal funds with the company's. They had emails sent to their personal accounts, and Herschkowitz had previously offered to pay certain fees or expenses out of his own funds, even if it meant mortgaging a property, the firm claimed.

The suit includes several state-law claims, including breach of contract, and a cause of action for piercing the corporate veil.

A Jones Day spokesman didn't immediately respond to a comment request. No one could be reached by phone at Serenity and no one immediately responded to an email sent through the company's website Wednesday evening.