Clinical trials of hydroxychloroquine are stopped temporarily

27 May 2020

Five clinical trials in Denmark testing the efficacy of hydroxychloroquine on COVID-19 are discontinued until further notice. This takes place after a major international study has indicated that there is no beneficial effect of using the product; in contrast, there could be serious adverse reactions.

All five clinical trials of hydroxychloroquine in Denmark will be discontinued until further notice.

This is a precautionary step taken on the basis of a study enrolling 96,000 coronavirus patients, which has just been published in the medical journal The Lancet. The study indicates that hydroxychloroquine, which is currently being tested as a treatment for COVID-19 patients in many countries including Denmark, has no beneficial effect. In contrast, the study suggests the product to be potentially harmful in patients. Among other things, the results indicate that the use of the medicine could lead to excess mortality and serious heart problems in COVID-19 patients.

“We fully understand that many hope that we will soon find or develop medicine that works on COVID-19. However, the results from the new study show that, for the sake of patient safety, we need to pause clinical trials with hydroxychloroquine and spend time reviewing both the efficacy and adverse reactions before deciding whether the tests can be resumed,” said Thomas Senderovitz, Director General of the Danish Medicines Agency.

The new study is a so-called observational study that can give us an indication of the medicine’s efficacy and adverse reactions. This requires a larger and more robust study to establish all causal relations and reach final conclusions and provide documentation on hydroxychloroquine’s efficacy and safety in COVID-19 patients.

The Danish Medicines Agency will consider a possible resumption of the clinical trials of hydroxychloroquine in COVID-19 patients once the safety has been investigated thoroughly.

Facts about hydroxychloroquine

Hydroxychloroquine is a medicine in tablet form authorised in the EU for the treatment of arthritis and skin diseases and for the prevention of malaria. The fact that the medicine is authorised means, in this context, that the authorities have granted a marketing authorisation to the company which manufactures the medicine. The marketing authorisation allows the company to sell the medicine for the treatment of precisely these diseases. The marketing authorisation has been granted based on documentation from the company that hydroxychloroquine is effective on these diseases and is safe to use. There is a medicine called chloroquine, and there is a medicine called hydroxychloroquine. Only hydroxychloroquine is sold in Denmark.

Since 23 March 2020, hydroxychloroquine in Denmark can only be prescribed by hospital doctors and specialist doctors specialising in rheumatic disorders, skin diseases and childhood diseases and used in clinical trials related to COVID-19.

Hydroxychloroquine is a safe treatment for patients suffering from autoimmune diseases or malaria.