As the long-running saga of Carl Icahn versus Forest rumbles on, the billionaire investor has taken another public shot at the firm, hauling it over the coals for failing to disclose warning letters from US regulators to its shareholders.

On August 1 Forest received a warning letter from the US Food and Drug Administration over a violation of promotional practices regarding Daliresp (roflumilast) by its sales representatives. 

In his letter, Icahn stressed that this came after another FDA warning letter in April last year over unethical sales practices by a Forest sales rep concerning Savella (milnacipran), and that both were issued after the company's settlement with the US Department of Justice in September 2010 regarding "similar unethical sales practices". 

As part of the settlement, Forest paid more than $300 million in fines and tied itself into a five-year Corporate Integrity Agreement to resolve the issue. 

"It is obviously worrisome that these practices would be ongoing at Forest given its chequered history in similar matters..[and]...Forest is one of the only companies lax enough to receive multiple warning letters while subject to a Corporate Integrity Agreement," he claims.

He also questions why Forest failed to disclose the warning letters to shareholders in the 10-Q the firm filed last week.

"This is yet another example of the stark lack of corporate governance at Forest where an ineffective Board made up largely of non-independent directors is unwilling or unable to hold Howard Solomon [chief executive and chairman of the board] and his management team accountable," he said.

Icahn, who owns 10% of the firm's stock, has been highly critical of Forest's management and has put forward four candidates for the board ahead of what is set to be a terse annual general meeting on August 15.

"We need to add strong independent directors, like Dan Ninivaggi and Pierre Legault, my two nominees recommended by ISS, as well as my other nominees, to instill much needed corporate governance and independence on the Board and bring this great company back to the shareholders," he argued.

Poison pill?

Earlier this week, Icahn also accused one of Forest's licensing deals - with Cypress Bioscience in 2004 - of containing a hidden so-called 'poison-pill' designed to protect the firm against a hostile takeover.

Icahn said in a statement that he is trying to get permission to publicise the related documents through a US court, because Forest "flatly refuses to let us tell other shareholders what those agreements say about a change of control" and the company "does not want the stockholders to know this information".

Forest argues that its joint venture agreements "are not structured to deter a potential acquisition," and that "change of control provisions in drug licensing agreements are standard and conventional".

In addition, Icahn has also referred to another - as yet undisclosed - issue relating to license agreements as "a smoking gun" that will be disclosed if permission to do so is received by the court.

But in a statement Forest has accused Icahn of making "false and misleading statements less than a week before our annual meeting in an egregious and desperate attempt to manipulate the results of the election".