Currently, there is not enough data to support the routine use of hydroxychloroquine (HCQ) or chloroquine (CQ) as therapies for COVID-19, concludes a systematic literature review published in Academic Emergency Medicine.
The review included seven completed clinical trials, five of which gave favourable results, and two that showed no change compared to controls. There are currently 29 registered clinical trials focusing on HCQ or CQ as a therapeutic route for COVID-19.
Thus far, the mainstay treatment for COVID-19 has been largely supportive. Of the experimental treatments investigated, HCQ and CQ have gained the most media attention due to their efficacy against SARS-CoV-2 in vitro, thought to be related to a rise in pH within endosomes, preventing viral entry. Also, CQ disables the ability of SARS-Cov-1 to bind to angiotensin-converting enzyme 2 (ACE2), a system thought to be utilised by SARS-Cov-2.
Primary outcomes prioritised in this study were mortality, clinical improvement, radiological improvement, clinical complications, adverse drug events, and negative SARS-CoV-2 PCR or nasopharyngeal swab post-treatment. While some trials showed a positive effect, details of study design are lacking.
Until results from clinical trials with more stringent study parameters are known, clinicians should defer from routine use of HCQ or CQ. the review authors concluded.