Impact of Doxycycline on Covid-19 Patients With Risk Factors of Disease Degradation: Dynamic, A Randomised Controlled Double-blind Trial

Abstract Background: The DYNAMIC study is based on three properties of tetracyclines. (1) Tetracyclines are known to chelate zinc from metalloproteases (MMPs). It is possible that their chelating activity may help to inhibit COVID-19 infection by limiting its ability to replicate in the host. (2) As seen with dengue virus, tetracyclines may also be able to inhibit the replication of positive polarity single-stranded RNA viruses, such as COVID-19. (3) In addition, tetracyclines are modulators of innate immunity (anti-inflammatory activity), a property that has been used to treat inflammatory skin diseases for many years. They could therefore participate in limiting the cytokine storm induced by COVID-19. The lipophilic nature of tetracyclines and their strong pulmonary penetration could allow them to inhibit viral replication at this level. Among tetracyclines, the advantages of doxycycline are triple: its long history of safety (infrequent side effects with no notable risks), the short duration of treatment and its low cost.Methods: By estimating the rate of patients presenting pulmonary signs requiring hospitalisation in at-risk patients infected with COVID-19 at 25%, we hypothesise that on doxycycline, this rate would decrease to 12%. The main objective involves 2 embedded hypotheses tested successively in case of rejection of the previous one: (i) Decrease the rate of patients requiring hospitalisation, (ii) Decrease the use of mechanical ventilatory assistance.Discussion: This study could have an impact on the management of COVID-19 risk factor patientsupstream of hospitals by general practitioners. These patients,if kept at home under experimental treatment, would participate in reducing the risk of dissemination of SAR-CoV-2in the population.Thus, this treatment would contribute to supporting the deconfinement strategy through blocking the viral infection early and reducing the contagious period.Trial Registration: On ClinicalTrials.gov, registration number NCT04371952, first published on 30 April 2020.