Four years after Mumbai-based Sun Pharmaceuticals was found unauthorisedly promoting and marketing letrozole, a drug prescribed for advanced breast cancer in postmenopausal women, for treating infertility in women, it has been cleared by the Indian Drugs Controller-General for that very purpose. What is shocking is that this approval has come despite the drug, developed by the Swiss company Novartis, being clearly marked contra-indicative for infertility treatment and in the absence of results from clinical trials that were designed and conducted properly. Since the drug approved in 1998 by the U.S. Food and Drug Administration was for treating advanced breast cancer, using the same drug for other purposes, would, by default, make it a new drug warranting full fledged clinical trials before regulatory approval. While animal studies conducted by the original developer have found harmful effects on the foetus when the drug is administered during the period of organogenesis, trials are under way on women for treating infertility and a clear verdict is yet to be returned. In fact, many of these trials do not meet the stringent requirements of the U.S. FDA or the European Agency for the Evaluation of Medicinal Products.
That the approval by the Indian authorities was based on cursory studies and was not backed by sufficient domestic clinical trial data makes a mockery of the country’s drug approval system. While there are instances where off-label use of a drug has “led the way while industry and regulatory agencies trailed behind,” such uses were not for conditions for which the drug was originally found to be contra-indicative. Though there are cases where drug manufacturers discourage the use of the drugs for unapproved conditions even when it has some desirable effects on patients, the way the Indian authorities have gone about approving letrozole leaves much to be desired. The letrozole experience does not portend well for a country that expects to be seen as a preferred destination for clinical trials.