US drugmaker Schering-Plough has offered to pay $435 million, and plead guilty to one charge of consipiracy, to finally bring to an end a six-year investigation by US regulators into the group's sales and marketing and pricing tactics.

The issues relate to before Schering-Plough's current management took over in April 2003, and concern allegations over illegal promotion of the group's brain cancer drugs Temodar (temozolomide) and Intron A for unapproved uses, as well as claims of price fixing for its popular antihistamine Claritin RediTabs.

S-P's white flag deal, which is yet to be approved by the US District Court for Massachusetts, would see the group pay, from litigation reserves already set aside, $255 million to lay to rest civil aspects of the investigation, while a subsidiary, Schering Sales Corp, will pay a criminal fine of $180 million and plead guilty to one count of conspiracy, to end the litigation.

And, according to media reports, the settlement also takes care of allegations that the firm paid doctors to start prescribing its products, as well as "sham advisory boards", "lavish entertainment" and "improper placement of clinical trials," reports the Financial Times.

Commenting on the move, Brent Saunders, senior vice president of global compliance and business practices at Schering-Plough Corp, said: "With this agreement, we are putting issues from the past behind us. It is another step as we transform Schering-Plough into a high-performance competitor for the long term."