He claims that failing to disclose the results of clinical trials kills patients and wastes money, and that government regulation is needed to put a stop to it.
Meanwhile, despite public commitments to such moves by some of the top pharma companies in the last few weeks, he is sceptical that full transparency will result.
Sir Iain has a particular interest in this issue, as chairman of the International Advisory Group for the metaRegister for Controlled Trials and the International Standard Randomised Controlled Trial Number scheme.
The letter notes that in 1996, Schering Healthcare published details of its ongoing clinical trials, while two years later GlaxoWellcome announced its decision to register and seek to report all its clinical trials.
But only now, and in response to accusations of biased under-reporting of research, has GlaxoSmithKline (GSK) announced that it intends to put in place some of the policies set out seven years ago by GlaxoWellcome, claims Sir Iain.
«It would be churlish not to welcome this, he writes, «but the past record of the pharmaceutical industry, and the reactions of some other companies to GSK's announcement, prompt deep scepticism that the industry will ever voluntarily implement ethical trial registration and publication policies.»