An industry watchdog will Roche over sales of its Xenical diet pill and the case is expected to spotlight sales tactics in the UK’s lucrative “slimming” market, The Financial Times writes.

The Prescription Medicines Code of Practice Authority, the pharmaceutical industry’s regulatory body, has opened an investigation into “alleged inducement and supply of Xenical.” The action follows a formal complaint from Ryta Kuzel, former head of Roche’s UK regulatory affairs, who was fired by the drugmaker shortly after the start of investigations into Xenical supplies in 2005.

Earlier this month, the paper wrote that Roche sold large quantities of Xenical to the operator of a chain of private UK diet clinics, in spite of suspicions at one stage that the pills were being sold illegally. Internal Roche documents shown in as part of Kuzel’s case indicated Roche execs raised concerns that Robin Huxley, the operator of a chain of private slimming clinics, might be selling Xenical not only to his own clients. but also on to the “grey market” beyond his direct control.

In spite of such concerns, Roche ruled itself satisified after internal audits and approved a discount scheme selling substantial volumes of Xenical to Huxley over two years. Huxley pleaded guilty in December to breaches of the Medicines Act following a two-year investigation by the Medicines and Healthcare Products Regulatory Agency.

However, an undercover “mystery patient exercise” in 2003, in which a Roche sales manager posed as a new client at Huxley’s Derbyshire Diet Clinic, showed that Huxley had personally prescribed Xenical, a prescription-only medicine, although he was neither a doctor nor a pharmacist. Roche also approved a $110,000 grant to “support” the purchase of another slimming clinic. Huxley assured Roche staff that the deal would permit further growth in Xenical sales.

The pharmaceutical industry code of practice forbids companies from providing inducements to health professionals to help sell their products. Roche argues that it was a victim of criminal conspiracy and believed Huxley to be a qualified pharmacist. The drugmaker says its funding to Mr Huxley was for “sponsorship and set-up” costs of the new clinic, and was “unrestricted,” and stresses that it cooperated fully with investigators and that the MRHA has never suggested any wrongdoing by Roche.

Kuzel won a substantial award for unfair dismissal against Roche, but not as a whistleblower over Xenical sales. She is considering a further appeal.